1. An electric field direction conversion structure comprising: a first waveguide configured to guide a first radio wave whose e l e c t r i c field is vibrated in a first direction along a second direction that is vertical to the first direction between a first end part and a second end part; a second waveguide configured to guide the first radio wave along the second direction between a third end part and a fourth end part, the second waveguide being cascade connected to the first waveguide by a connection of the first end part and the third end part; an input and output end configured to multiplex the first radio wave from the first waveguide and the first radio wave from the second waveguide and outputs the multiplexed radio wave, and outputs the first radio wave branched off from a radio wave from outside to the first and second waveguides at a connection portion between the first end part and the third end part; a first waveguide shift portion having a fifth end part connected to the second end part of the first waveguide and a sixth end part that is shifted from the fifth end part in the first direction, a second radio wave having an electric field vibrated in the second direction being input or output to or from the sixth end part along the second direction; and a second waveguide shift portion having a seventh end part connected to the fourth end part of the second waveguide and an eighth end part that is shifted from the seventh end part in the first direction and in a direction opposite to the sixth end part, the second radio wave having an electric field vibrated in the second direction being input or output to or from the eighth end part along the second direction, wherein: the vibration direction of an electric field of a radio wave passing through the sixth end part of the first waveguide shift portion is rotated by 90° about a third direction that is vertical to the first and second directions, and the vibration direction of an electric field of a radio wave passing through the eighth end part of the second waveguide shift portion is rotated by 90° about the third direction in a direction the same as the rotational direction in the sixth end part.

2. The electric field direction conversion structure according to Claim 1, wherein: the first waveguide shift portion is formed of a curved waveguide that connects the fifth end part and the sixth end part, and the second waveguide shift portion is formed of a curved waveguide that connects the seventh end part and the eighth end part.

3. The electric field direction conversion structure according to Claim 2, wherein the center axis of the waveguide that constitutes the first waveguide shift portion and the second waveguide shift portion is the second direction, and the waveguide has a step-like shape and is shifted in a step-like manner along the first direction.

4. The electric field direction conversion structure according to Claim 2 or 3, wherein the distance between the input and output end and the sixth end part is equal to the distance between the input and output end and the eighth end part.

5. A planar antenna comprising: first to fourth antenna elements that are arranged in a grid on a plane that is vertical to the first direction, each of the first to fourth antenna elements combining a p l u r a l i t y of polarization waves and t r a n s m i t t i n g a polarization multiplexed signal or separating a polarization multiplexed signal that has been received into a plurality of polarization waves; 25 a first waveguide part configured to output the second radio wave to the first to fourth antenna elements or receives the second radio wave that has been separated by the first to fourth antenna elements; and a second waveguide part configured to output a third radio wave having an electric field whose vibration direction is vertical to the vibration direction of the electric field of the first and second radio waves to the first to fourth antenna elements or receives the third radio wave separated by the first to fourth antenna elements, wherein the first waveguide part comprises: the electric field direction conversion structure according to any one of Claims 2 to 4; a third waveguide having one end connected to the first antenna element and another end connected to the second antenna element, the center of the third waveguide being connected to the sixth end part, and the third waveguide extending in the third direction; and a fourth waveguide having one end connected to the third antenna element and another end connected to the fourth antenna element, the center of the fourth waveguide being connected to the eighth end part, and the fourth waveguide extending in the third direction.

6. The planar antenna according to Claim 5, wherein the distance between the center of the third waveguide and the first antenna element, the distance between the center of the third waveguide and the second antenna element, the distance between the center of the fourth waveguide and the third antenna element, and the distance between the center of the fourth waveguide and the fourth antenna element are equal to one another.

7. The planar antenna according to Claim 5 or 6, wherein: the first to fourth antenna elements each comprise: 26 a polarization wave separation/combination portion configured to separate the second radio wave and the third radio wave included in the polarization multiplexed signal or combines the second radio wave and the third radio wave into the polarization multiplexed signal; a horn antenna portion configured to transmit the polarization multiplexed signal from the polarization wave separation/combination portion or transmits the polarization multiplexed signal that has been received to the polarization wave separation/combination portion, and the polarization wave separation/combination portion receives or outputs the second radio wave through an opening on a plane vertical to the third direction and receives or outputs the third radio wave through an opening on a bottom surface vertical to the first direction.

8. The planar antenna according to Claim 7, wherein: the second waveguide part is connected to the opening on the bottom surface of the polarization wave separation/combination portion of each of the first to fourth antenna elements, and the second waveguide part converts the third radio wave from the opening on the bottom surface of the polarization wave separation/combination portion of each of the first to fourth antenna elements into the first radio wave, combines the resulting radio waves in phase with each other, and outputs the combined radio wave or separates the first radio wave input from outside to convert the first radio wave into the third radio wave and guides the third radio wave after the conversion to the opening on the bottom surface of the polarization wave separation/combination portion of each of the first to fourth antenna elements in the same phase. 27

9. The planar antenna according to any one of Claims 5 to 8, wherein the first waveguide part and the second waveguide part are formed in different layers laminated to each other in the first direction.

10. A planar antenna comprising: a plurality of antenna elements arranged on a first plane; a first waveguide part configured to receive or outputs a first radio wave from or to the plurality of antenna elements, the first radio wave being used for orthogonal polarization transmission; and a second waveguide part configured to receive or outputs a second radio wave whose polarization plane is perpendicular to the polarization plane of the first radio wave from or to the plurality of antenna elements, wherein the first waveguide part and the second waveguide part are laminated to each other substantially parallel to the first plane.

11. The planar antenna according to Claim 10, wherein: the first waveguide part comprises an electric field direction conversion portion having a first end part connected to a first antenna element, a second end part connected to a second antenna element, and an input and output end through which a third radio wave having a polarization plane perpendicular to the polarization plane of the first radio wave is input or output, the polarization plane of the third radio wave is rotated in such a way that the polarization plane of the third radio wave matches the polarization plane of the first radio wave while the third radio wave is guided from the input and output end to the first and second end parts, and the polarization plane of the first radio wave is rotated in such a way that the polarization plane of the first radio wave matches the polarization plane of the third radio wave while the first radio wave is guided from the first and second end parts to the input and output end. 28

12. The planar antenna according to Claim 11, wherein: the electric field direction conversion portion is a waveguide that couples the first end part and the second end part, and the input and output end is provided at the center of the waveguide that is provided between the first end part and the second end part.

DESCRIPTION
ELECTRIC FIELD DIRECTION CONVERSION STRUCTURE AND
PLANAR ANTENNA
5 Technical Field
[0 00 1]
The prese nt i nv ent ion rel ate s to an ele ct ric fi eld di r ect ion
conv ers ion structure and a pla nar an te nna .
Background Art
10 [0002]
In recent ye ars , in ac cord ance wit h an inc r ea s e i n
commu nicati on t raffic , t he r e has been a d ema nd t o i nc r ease th e
commu nic ati on capa cit y i n comm uni cat i on s ys tem s s uch as point -t o -
point. To meet this demand, it is known to use a communication
15 s ys tem tha t us es a pol arize d wa ve s ha r ed ant en na c apable o f
t r ansmitt ing or re cei vi ng a po la riz ati on m ulti plex e d sig nal i nclud in g
t wo pol ariz atio n wa ve si gnals h avi ng pol ariz atio n pl an es pe rp endi cul ar
t o each ot he r i n ord er to perfo rm commu ni cati on b y th e polar iz ation
m ul tipl ex ed si gnal . Ac cordin g to th i s commu ni catio n s ystem ,
20 i nformat ion can b e c arri ed o n e ac h o f th e pol arizatio n wa ve si gna ls ,
whereb y it i s possibl e to d oubl e th e c ommu ni cation cap aci t y co mp ar ed
t o t he c ase in w hic h th e pol arization m ul tipl ex ed si gna l i s n ot used .
[0 00 3]
A m eth od of tran s mittin g or r ec eivin g pol arization mu ltip lex ed
25 si gn als b y a p arabol a ant enn a i s a lre ad y kn own . S in ce th e p ara bol a
antenna h as a re lat iv el y l arge th ic kne ss and affe ct s win d l oad s or
l andscap e s, howev er, a pla nar ant en na ha s b een i ntrod uce d.
[0 00 4]
As an ex ample of a pol ariz ed w av e sh ared pl an ar ant en na, a
30 pl an ar ant enn a ha vin g a st r uct ure in wh ic h cond uct ors, wh ic h are
antenna ele m ent s, a r e con ne cte d by mic ro strip lin es (p owe r feed li ne s )
i s disclose d (P at ent Lit eratu r e 1 ) .
[0 00 5]
2
A polariz ed w av e sha r ed squ are ope ni ng ante nna cap abl e of
effi ci entl y separ atin g o r comb i ning a ve r ti cal pol arization wave and a
horizo nta l polari z ation wav e whe n receiv ing a po la riz atio n mul t i plex ed
si gn al b y a sq uar e ope ni ng o r t ran sm itti ng a p ol ar izat ion mult ipl exed
5 si gn al f rom t he sq ua r e open ing is discl os ed ( Pat ent Lite r atu re 2 ) .
[0 00 6]
Anoth er an te nn a appa r atus ca pa bl e o f atte nuat ing, w hen a
t r ansmission is pe r f or m ed usin g rect an gular wave gui de s throu gh whi ch
hi gher -o rder m od es c an be pro pagated, th e hi gh er -o r de r mod es th at can
10 be prop aga ted i s d is cl osed (Pa tent Lite r ature 3 ) .
Ci tation L ist
Patent Literature
[0 00 7]
[ P aten t Li t erat ure 1] J apa nese U nex amined Pat en t Appl ica t i on
15 Publication No. 2008-283352
[ P aten t Li t erat ure 2] J apa nese U nex amined Pa t en t Appl ica tio n
Publication No. 2003-69337
[ P aten t Li t erat ure 3] J apa nese U nex amined Pat en t Appl ica t i on
Publication No. 2008-148149
20 Summary of Invention
Technical Problem
[0 00 8]
However , th e prese nt i nvento r s have fo und th e f oll owin g
problems in the aforementioned methods . The planar antenna formed
25 of th e m i crostrip l i nes (e.g., Pa tent Lit erat ure 1 ) is not suit abl e fo r
hi gh - f requenc y c ommu ni cati on sin ce it su ffers a su bst anti al loss in a
hi gh - f requenc y re gion , w hi ch cau s es a red ucti on in th e ant enn a ga i n .
In o rd er to s upp r ess t he loss in t he h igh - f r equ en c y re gi on , it i s d esi red
t o guid e v ertical p ol ariz ati on wave s and horiz ontal pol arizatio n wav e s
30 i nclu ded i n t he p ola r izat ion m ul t ipl ex ed s i gnal to b e t ransmit t ed o r
r ecei ved b y w avegui de s .
[0 00 9]
3
When a waveguide path in the planar antenna is formed using
t he wavegui de s , the arran gement o f t he w av eguid es is re stricted
comp ared t o t he case in wh ich mi cros tripli nes are u s ed. T her efore , th e
t hi ck ness of t he p la na r ant en na that us es th e wa ve gui des incr ea s es . On
5 t he oth er h and , whil e th e aforem ent ioned p ola r ized wa ve sh ared s qu are
openi ng a nten na (Pa tent Lit erat ure 2 ) an d t he ante nn a appar atu s
(P aten t Li te r at ure 3 ) ca n be use d f or th e pl anar ante nna th at use s the
wa vegui des , t he y do not co ntrib ut e to sup pr es si on of th e t hick ne ss of
t he p l anar ant enna .
10 [0010]
The prese nt i nv ent ion has b een m ade i n vi ew of the
aforem enti on ed circ um st an ces a nd aims to p rov ide a l ow -l os s and thi n
polarize d wav e s ha r ed pl an ar ant enn a .
Solution to Problem
15 [0011]
An el ect r i c field dire ctio n c onv ersi on struct ure accordi ng t o an
ex em plar y a sp ect o f the prese nt i nventio n in cl ude s : a first wav egu i de
t hat gu ide s a fi rst ra di o wa ve w hos e el ec t ri c fie ld i s v ib r at e d in a first
di rect ion alon g a se cond d ire ct i on th at i s v erti ca l to th e fi rst d ire cti on
20 between a fi rst end p art and a secon d en d part; a s ec ond w ave guid e
t hat gu ide s th e f irst radio wav e alo ng th e s eco nd di rectio n be t ween a
t hi rd en d pa rt a nd a fou rt h end p art, the se co nd wav egu id e b ein g
ca scade con nect ed t o th e first w av eg ui de b y a co nnecti on of the fi r st
end p art and th e third en d pa r t; an i nput a nd o ut put e nd th at
25 m ul tipl ex es th e first radio wav e from th e fi rst w av eguid e an d th e first
radio wave from the second waveguide and outputs the multiplexed
r adio w av e, and o utpu ts t he firs t r adio wav e bran ch ed o ff fr om a radi o
wa ve fr om outsid e to th e fi rst and s econd w av eguid es a t a con ne ction
portion bet ween t he first end p art a nd the t hird en d pa r t; a first
30 wa vegui de shift p ortio n h avi ng a fifth end part c onn ec ted to th e s eco n d
end p art of t he fi r st waveguid e and a s ixth end p ar t t hat i s s hift ed from
t he fifth end par t in th e fi r st di rect ion , a se cond r adio wav e hav in g an
el ectric fi eld vi brat ed in th e s eco nd di r ecti on b ein g i npu t or outp ut to
4
or from t he six th end part al ong t h e s econ d di r ectio n; a nd a se con d
wa vegui de shift p ortio n h avi ng a s ev enth end p art con ne ct ed to the
f ourth en d part o f the s econd wavegu ide and an eigh th e nd part t hat is
sh i ft ed from th e s ev enth end p art i n the first di r ectio n and i n a
5 di rect ion o pposit e to t he sixt h end p art , th e s econ d r adi o wav e ha vi ng
an el ect r ic fiel d vib rat ed in t he s ec ond di rect ion be ing inp ut o r out put
t o o r f ro m t he eight h end p art alo ng th e s econ d direction , i n whi ch: t he
vi brati on directi on o f an el ect ric fi el d of a r adi o wav e p as si ng throu gh
t he s ixth end p art o f the fi r st wavegui de s hift po r t i on is rotat ed b y 9 0°
10 about a thi r d di r ec ti on th at is verti ca l t o t he fi rs t an d s ec ond
di rect ion s, and t he vib r ati on dire cti on of an el ectric fi eld of a rad io
wa ve passin g th rou gh t he eigh th end par t of t he se con d wav egu id e shi ft
portion i s rot ate d b y 90° abou t th e t hird directi on i n a d ire ctio n th e
s am e as th e rot ation al directi on in t he six th end part.
15 [0012]
A p lan ar an t enn a a cc ord ing t o an ex empl ar y asp ect of t he
pres ent i nv en tion i ncl udes a pl ural it y o f antenna el em ents a r ran ged on
a fi rst p lan e , a fi rst w av eguid e p art that r ec eives o r o utput s a first
r adio w av e from o r t o th e pl uralit y o f an t enn a el eme nts , the fi rst rad io
20 wa ve bei ng receiv ed o r out put b y ort hogo nal p ola riz a ti on tra ns miss ion ,
and a se con d wav egu ide p art th at receiv es or o utpu t s a s eco nd radi o
wa ve who s e polariz ati on p lane is p erp endi cular t o th e po la riz ati on
pl an e of th e fi rst ra di o wave from o r t o the plu r al it y of anten na
el em ent s , i n which t he firs t wa ve gui de p art a nd th e s econ d wa ve gu ide
25 pa rt a r e l ami nat ed to each o ther s ub st antiall y pa r all el to the fi r st plane .
Advantageous Effects of Invention
[0 01 3]
Accordin g t o the p r esent in ve nt i on, it is p os si bl e to p r ovid e a
l ow -l oss an d thin po la riz ed w av e sh are d pla na r ant enna.
30 Brief Description of Drawings
[0 01 4]
F i g. 1 i s a pe rsp ectiv e vi ew s how ing th e ext erio r of a p lanar
antenna 100 acco r din g to a fi rst ex empl ar y em bodi me nt ;
5
F i g. 2 i s a p ers pective , see - thro ugh vie w sc hem aticall y s ho win g
a con fi gura ti on o f a n a nt en na 10 a cc ord ing t o t he fi r st ex em pla r y
embodiment;
F i g. 3 i s a p ers pective , see - thro ugh vie w sho wing a st r uctu re of
5 t he an ten na in w hic h a ho rn ant enn a po rtion of the ant enna acco rd i ng
t o t he f i rst ex em pl ar y em bo dim en t i s s how n i n a tra nsp arent ma nn er ;
F i g. 4 i s a p ers pective , see - thro ugh vie w sho wing a
confi gurat ion of a n antenn a ce ll 1 ta ken al on g t he lin e V -V of Fig. 3;
F i g. 5 i s a p ers pective cros s -se cti on al vie w of t he ant en na c ell 1
10 t aken alo ng the l i ne V-V of Fig. 3 ;
F i g. 6 i s a sid e vi ew of a p ola riz ati on w ave
s eparation /comb inat ion po rt ion 3 show i ng ho riz o nt al p ola riz ati on
wa ves W H in t he pol arizatio n wav e s ep aratio n/c ombi natio n po rtio n 3 ;
F i g. 7 i s a sid e vi ew s how in g a p art of the pol arizat ion w ave
15 s eparation /comb inat ion po rt ion 3 th at su bst antiall y a f f ects th e
horizo nta l polari z ation wav e s W H ;
F i g. 8 i s a sid e vi ew of th e pol ari z ation wave
s eparation /comb inat ion po rt ion 3 showi ng ve r t i cal pol arizatio n wa ve s
WV in th e polariz at ion wave se paratio n/c om bin atio n portio n 3;
20 F i g. 9 i s a sid e vie w s how in g a p art of the pol arizat ion w ave
s eparation /comb inat ion po rt ion 3 th at su bs ta nti all y affe ct s t he vert ic al
polarization waves WV;
F i g. 1 0 is a di agra m sho win g t he v erti cal po la riz ati on w av es
guided b y a wav egui de po rti on 4 in t he a nte nna 1 0;
25 F i g. 1 1 is a cro ss - s ectio nal v ie w o f an e le ct ric fi eld dire ctio n
conv ers ion portio n 43 on a Y-Z pl an e ; and
F i g. 1 2 is a di agra m sho win g t he h oriz ontal pol arizatio n wav es
guided b y a w aveguid e portio n 5 in th e a nte nna 1 0.
Description of Embodiments
30 [0015]
Exempl ar y emb odi men ts of th e present inv enti on wil l b e
des crib ed b elow with r eferenc e t o t he d r awin gs . In th e d raw ings, t he
6
s am e el em ents are d enoted b y t he s ame r efe rence s ym bol s, a nd t hus a
r epeated de scri ption i s omit ted as n ee ded .
[0 01 6]
First Exemplary Embodiment
5 A planar antenna 100 according to a first exemplary embodiment
wi ll be desc rib ed . T he p lan ar ant enn a 1 0 0 re ce i ves a sign al obt ain ed
b y com bini ng t wo pol arization waves , sep arat es the r ecei ve d sign al
i nt o a verti cal polariza tio n wav e (h erei nafter t his wav e wil l als o be
r eferred to as a s econ d rad i o wav e ) a nd a h oriz ontal pol arizatio n wav e
10 ( he r ei naft er t his wa ve w ill also b e refe r r ed to as a thi r d radio w av e ),
and output s t he verti cal polarizat ion wave and th e ho ri zont al
polariza tion wav e , o r combi nes a ve r t i cal pol arizat ion wa ve and a
horizo nta l polari z ation wav e th at have b ee n in put and sen ds t he
combi ned si gn al t o out sid e . In th e foll owi ng des cr iption , th e
15 polariza tion wave is al so r efe r r ed t o a s a rad io w av e h avi ng an e le ct ric
fi eld t hat is vib rated in one dire ction .
[0 01 7]
F i g. 1 i s a pe rsp ectiv e vi ew s how ing th e ext erio r of th e pl ana r
antenna 100 a ccordi ng t o th e f irs t exem pla r y em bo dim ent . The plana r
20 antenna 100 i ncl ud es antennas 1 0, each of t he ante nn as 10 inc ludin g
f our ant e nna cells 1, arran ged in an arra y. In Fi g. 1, the p lan ar
antenna 100 i s a p lan ar ant enn a , a prin cip al plane o f which i s an X-Y
pl an e, a nd i ncl ud es ante nn as 10 , e ac h of t he a nt en nas 10 i nclu din g four
antenna cel ls 1 a rrange d in a grid on t he X -Y p lane. T h e ante nn as 10
25 ea ch inc lud e 2 ×2=4 a nte nna cell s 1 a r r an ged in the gr id. Th at is, th e
pl an ar ant enn a 1 0 0 inc l udes th e i ntegr at ed ant en nas 10, whi ch a re
sm al l pl ana r an te nn as .
[0 01 8]
In th is ex am ple , th e plan ar a nt enn a 1 00 i ncl ud es fo ur ant enn as
30 10 i n an X directi on (t he X di r ec tio n is al s o referre d t o as a th ird
di rect ion ) and fo ur an t enn as 10 i n a Y dire ctio n (th e Y di rect ion is
al s o refe r r ed to a s a s ec ond dire cti on ), t hat i s, 4 ×4 =16 ant enn as 10 in
t ot al . Therefo r e, th e pla nar an ten na 10 0 in cludes eig ht anten na cel l s 1
7
i n t he X directio n and ei ght ant enna cel ls 1 in t he Y di r ectio n , th at i s,
8×8=64 antenn a ce l l s 1 in t ot al .
[0 01 9]
Whil e not shown in Fi g. 1, t he a nt enna cell s 1 each i nc lu de a
5 horn an ten na po rt ion th at tra nsm i ts and r ecei ves a po la rizatio n
m ul tipl ex ed si gnal an d a po la riz ati on wav e s ep aratio n/ com bi nat ion
portion t hat com bin es or sep arat es a ve rti cal p ola r i zati on w ave and a
horizo nta l polari z ation wav e . Fu rt her , th e a nt enn a c el ls 1 ea ch includ e
a wav egu id e po rtion t hat conn ect s th e an t en na cells to guid e th e
10 ve rtical p ol arizati on wav e and t he h ori zon tal p ol arizat ion wave . Th e
antenna cel l 1 , t he p ola rizat ion w ave se pa r at ion/ com bi nati on p orti on ,
and th e w avegui de p ort ion are e ac h f orme d o f a ho l l ow t ube stru ctu r e
i n a c ondu ctiv e m a teri al s uch as m et al .
[0 02 0]
15 In t his ex empl ary emb odiment , t he p ol ariz ati on wave h avi ng a n
el ectric fi eld th at is v ibra ted in t he Y d ir ec ti on is re ferred to as t he
ve rtical p ol arizati on wav e and th e pol ari zatio n wa ve h avi ng an e le ct ric
fi eld th at is v ibra t e d i n th e X di recti on i s re ferred t o as th e ho r izo nt al
polariza tion wave .
20 [0021]
Next , t he s truc ture of th e an tenn a cell 1 will be des crib ed . Fi g.
2 i s a p erspe ctiv e, se e -th r ough vi ew s ch em ati call y sho win g th e
st ru ctu r e of th e a nte nna 1 0 ac co rdi ng to t he fi r st ex em pla r y
em bod ime nt . Fig. 2 sh ow s onl y tu be wal ls of th e t ub e s tr uctu r e wh ich
25 i s vi ew ed t h rou gh th e co nductiv e ma t erial t hat cover s t he
aforem enti on ed t ube stru ct ure t o exp l ain the structure s of th e
polariza tion wave s epa ration /co m binat ion p ort io n an d th e wav egu ide
portion con nect ed to t he ante nn a cell 1 . Fi g. 3 i s a perspe cti ve, s ee -
t hrough vie w sh owin g the st r uctu re o f t he ant en na 10 in w hi ch t he ho rn
30 antenna portion 2 of the ant enna 10 sh own in Fi g. 2 is sho wn in a
t r anspar ent mann er .
[0 022]
8
As sho wn in Fig. 2, th e a n te nn a 1 0 in clu des 2 ×2= 4 an te nna cell s
1 arran ged i n t he gri d. Th e an tenn a cell s 1 ea ch includ e th e ho r n
antenna portion 2 and a pol a r iz a t io n wav e s epa r a t i on /c ombi n a t io n
portion 3.
5 [0023]
The a nt enn a c e l l 1 tra nsmit s t he pol a r i z a t i o n multip l ex ed si gnal
t o o u t s id e or receiv es th e p ola r i z a t ion mult i p l exe d si gnal from o u t s i de
vi a th e ho rn antenn a portio n 2 . In t h i s ex empl ary em bod i m ent , th e
polariza t i on mul t i p l exed si gna l t r ansmi t te d or receiv ed b y th e ant enn a
10 cell 1 i ncl ud es t he ve r t i cal pol a r i z a t i o n wave a nd th e ho riz on t al
polariza t i on wave .
[0 02 4]
The pol a r iz a t i on wave se p a r a t i on/ co mbi n a t i on po r t i on 3 h as a
f uncti on o f s ep a r a t i n g th e pol a r iz a t i on m ul t i p l ex ed si gn al i n to t he
15 ve r t i c a l p ol a r i z a t i on wav e and t he h ori zon t a l pol a r iz a t io n wa ve or
combi ni ng the vert ica l polariz a t io n wav e a nd th e ho r izont al
pol a r i z a t i o n wave into th e p ola r i z a t i on m u l t i plex e d sig nal .
[0 02 5]
Fig. 4 i s a pe r s pect i ve , see - t h ro ugh vie w sho wing a
20 confi gurat ion of th e antenn a ce l l 1 ta ken al on g t h e lin e V-V of Fig. 3.
F i g. 4 s hows onl y the tub e w a l l s of t he tu be st r u c t u r e whi ch is v iewed
t hrough the c on duct i ve m a t e r i al t hat co v e r s th e t ube stru ctu r e in orde r
t o ex pl a in the st ru ctu r e s o f th e po la r i z a t i on w ave
s e p a r a t i o n /comb inat ion po rt ion an d t he wa ve guide p o r t i on conn ec t ed to
25 t he an t en na cell 1 . Fig. 5 is a pe r s p e c t iv e c r oss -s ec ti onal vi ew o f th e
antenna cel l 1 t ak en a lo ng th e l i ne V -V o f Fi g. 3. For th e sak e o f
simpl i f ic a t i on of th e d rawi n g s , th e h orn ant enn a po r t i on 2 i s no t s ho wn
i n Fi gs . 4 a nd 5.
[0 02 6]
30 As sho wn in Figs. 4 a nd 5, th e po l a r i z a t i on w ave
s e p a r a t i o n /comb inat ion po rt ion 3 is p rovi de d in su ch a w a y th at its
area b ec ome s s m a l l e r i n a st ep wise man ner as it ext en ds do wnw ard (Z(-
) s i d e ) . An openi ng 3a is pro vi ded on a s urface o f t he p ol a r i z a t ion
9
wa ve s epa r ation /combi natio n po rtio n 3 th at i s ve rt i cal t o the X
di rect ion . An openin g 3b i s p r ovided on a bo ttom su r face (Z( -) sid e
end p art ) o f th e p olariz at ion wave se parati on/ combi nat ion po rtion 3.
[0 02 7]
5 The pol ariz ati on multi plex e d si gn al th at has be en p ro pagat ed
f r om t he horn an te nna po r tion 2 to t he pol ariz atio n wa ve
s eparation /comb inat ion po rt ion 3 i s , as wi ll b e d es crib ed lat er,
s eparated i nt o th e ve rtical p ola r izati on w ave W V and t he h oriz ont al
polariza tion wave W H i n t he pol ariz at ion wav e separ at ion/combi nat i on
10 portion 3.
[0 02 8]
The ope nin g 3 a on t he si de su r f ace o f t he p ola riz ati on w ave
s eparation /comb inat ion po rt ion 3 o f each o f t he ant en na cell s 1 i s
conn ect ed t o a wav egui de p ort ion 4 (t his wav egu ide portio n 4 i s als o
15 r eferred to as a fi rst w av eguid e p art ). At th e ti me o f receptio n , the
ve rtical p ol arizati on wav e s W V a r e p ro pa gated to t he wave guid e
portion 4 from th e p ola rizat ion w ave se pa r at ion/ com bi nati on p orti on s 3
of the resp ec t i ve a nte nn a cell s 1 via th e o pe ni ng s 3 a. In the f oll owi ng
des crip tion , t he p ola r iz at ion w av e ha vi ng an e le ct ric fi eld th at is
20 propagati ng thro ugh t he wave guid e and i s vib r at ed i n on e di rectio n i s
r eferred to as a ra dio wave o r an ele ctromagneti c wa ve havin g an
el ectric fi eld th at is v ibra ted in o ne di r ect i on . Th e w av eguid e po rt i on
4 conv erts and co mbin es th e v ert i cal po la riz ati on w ave s W V th at ha v e
be en prop agat ed i nto a pol arization wav e hav in g an el ect ri c f iel d t hat
25 i s vib r at ed i n a Z di r ecti on (t his di rect ion wil l al so be r eferred t o as a
fi rst di r ectio n ) (he r ei naft er thi s pol ariz atio n wa ve is refe r r ed to as a Z
polariza tion wave W Z or a fi rst radi o wa ve ) an d outpu ts t he com bin ed
Z pol ariz atio n wa ve W Z t o outsid e ( e.g., a tra ns cei ver ). At the t im e of
t r ansmission , t he Z pol arizatio n wa ve W Z i s inp ut to t he wave guid e
30 portion 4 from out si de ( e.g., the tr an sceiv er ). T he w av eguid e po r ti on
4 conv erts th e Z pol arizatio n wa ve W Z tha t has be en i np ut int o th e
ve rtical p ol arizati on wav e W V , separate s t he vert ic al pol ariz ation wav e
WV aft er th e conv e rsion , a nd gui des t he sepa r at ed w av es t o t he
10
polariza tion wave s epa ration /co m binat ion p ort ion 3 o f th e resp ectiv e
antenna cel l s 1.
[0 02 9]
The ope nin g 3 b on th e b otto m su rface o f t he p ola r izat ion wave
5 s eparation /comb inat ion po rt ion 3 o f each o f t he ant en na cell s 1 i s
conn ect ed t o a wav egui de p ort ion 5 (i t is al s o r efe rred to a s a s eco nd
wa vegui de p art ) . At t he tim e of recepti on , th e horiz ont al pol ariz ati on
wa ves W H are i nput t o the wav egui de po rt ion 5 from t he p ola riz a ti on
wa ve s epa r ation /combi natio n po rtio ns 3 of the r esp ectiv e ant enn a cel ls
10 1 vi a th e o peni ng s 3 b . Th e ho riz ont al po l ariz ati on wave s W H are
converted into the Z polarization wave s WZ when the propagation
di rect ion i s ch an ged at th e con nect ion portion bet we en the po la riz a ti on
wa ve s epa r atio n / com bin ation p ortio n 3 an d t he wa ve gui de p orti on 5 .
The waveguide portion 5 combines the Z polarization waves WZ after
15 the conversion and outputs the combined Z polarization wave WZ to
outs ide (e .g., the t rans ce ive r ) . At t he tim e of t ransmi s sion , th e Z
polariza tion wave W Z is i nput to t he wave gui de porti on 5 from ou t sid e
( e. g. , a t r ans mitt er) . Th e w ave gu id e portion 5 s epa r ates th e Z
polariza tion wave W Z th at h as be en inp ut a nd guid es th e s ep arated
20 wa ves t o the pol ariz ati on wave se parat ion /co mb ination po rti ons 3 of
t he r esp ect ive a nt enn a c el ls 1 . Th e Z p ol arizat ion wave W Z i s
conv erte d i nto the ho riz ont al po l ariz atio n wav e wh en th e prop aga t ion
di rect ion i s ch an ged at th e con nect ion portion bet we en the po la riz a ti on
wa ve s epa r ation /combi natio n po rtio n 3 an d th e wa ve gui de p orti on 5 .
25 [0030]
F i g. 6 i s a sid e vi ew of t he pol ari z ation wave
s eparation /comb inat ion po rt ion 3 showi ng th e horiz ont al pol ariz ation
wa ves W H in th e pol arizatio n wav e s ep aratio n/c ombi natio n po rtio n 3 .
As sho wn in Fi g. 6, th e ho r i zont a l polariz atio n wav e s W H are
30 polariza tion waves w hos e el ect r i c fi eld s are vi brat ed in the X dire cti on.
In th is case , s in ce th e wav egu id e portion 4 conn ect ed to th e op enin g 3a
on t he sid e su rfac e s erv es as a cuto ff w av eguid e wi th respect to th e
horizo nta l p ol ariz at ion wave s W H , it c an be r ega r ded t hat t he
11
wa vegui de p ort ion 4 i s el ect ric all y s hort - circ uit ed . F i g. 7 is a sid e
vi ew sho win g a part of th e pol arizat ion wave s epa r atio n/c ombi natio n
portion 3 that s ubsta nt ial l y affects th e h oriz ontal pol ari zat ion w av es
WH . As shown in Fig. 7, it can be regarded that the opening 3a and
5 t he wavegui de p ortio n 4 do not exi st for th e horiz ont al polar iz ation
waves WH.
[0 03 1]
F i g. 8 i s a si de view of th e pol ari z ation wave
s eparation /comb inat ion po rt ion 3 showi ng th e v erti cal pol ariz atio n
10 wa ves W V in th e pol arizatio n wav e s ep aratio n/c ombi natio n po rtio n 3 .
As sho wn in Fi g. 8, th e v ert i cal pol arizatio n wa ve s W V are
polariza tion waves w hos e el ect r i c fi eld s are vi brat ed in the Y di r ect ion .
In th is case , s in ce th e wav egu id e p ortio n 5 con nect ed t o th e op eni ng 3b
on t he b otto m su rfa ce se r ves as a c ut off wa ve gui de with respect t o th e
15 ve rtical p ol arizati on wav e s W V, it c an be r ega rd ed th at t he wav egu i de
portion 5 is el ectric al l y s ho rt -c ircuit ed . Fi g. 9 is a sid e vi ew sh owi ng
a part o f t he polariza tio n wav e s ep aratio n/ combin ati on porti on 3 tha t
su bst anti all y affects th e v ert ical po la riz ati on w ave s W V. As s how n i n
F i g. 8 , i t can be r egard ed t hat t he area from the l ower p art of the
20 polariza tion wave s epa ration /co m binat ion p ort ion 3 to th e op eni ng 3b
and th e wa ve gu id e po rtio n 5 do not exist for t he v erti cal po la riz ati on
waves WV.
[0 03 2]
F r om t he aforem entio ne d d esc ri pt i on , it wi ll b e un de rstoo d th at
25 t he h orizo ntal po lariz a ti o n w av e s W H prop agat e f r om the pol ariz atio n
wa ve s epa r a ti on/ com bi nat ion p ort ion 3 to the wav egu i de p ortio n 5 vi a
t he o peni ng 3b a nd the v ert i cal pol arizatio n wa ve s W V prop aga t e from
t he p ol arizat ion wave se parati on/ co m bi nation portion 3 to t he
wa vegui de p ort ion 4 via th e op enin g 3a.
30 [0033]
Next , exem pla r y a spe cts o f wa ve gui din g of the verti ca l
polarization waves WV and the horizontal polarization waves WH in
t he an ten na 10 will b e d escri bed . F i g. 10 i s a dia gr am sh owi ng t he
12
ve rtical p ol arizati on wav es W V guided b y t he wav egu i de p ortio n 4 i n
t he anten na 1 0 . In Fig. 10 , anten na cel l s 1 a to 1d (t he antenna cel l s 1 a
t o 1 d ar e als o refe r r ed to as fi r st to f ourth an te nna el ements ,
r esp ectiv el y) are p r ovid ed in th e a nt enn a 10 . Th e a nte nna cell 1 a
5 co rrespo nds t o th e a foremen tion ed a nte nn a cell 1. Th e an ten na cel l 1b
i s lin e s ym m et ric t o t he ante nna cell 1a w ith respect t o th e Y ax i s.
Th e a nt enn a c ell 1 c i s lin e s ym me t ri c to th e ant enn a c ell 1a with
r esp ect to t he X axis. T he ant enna cel l 1 d is l i ne s ym met ric t o th e
antenna cel l 1 b with resp ect to t he Y ax is .
10 [0034]
The ope nin g 3 a of th e an tenn a cell 1 a and t he op enin g 3a o f t he
antenna cel l 1 b are op posed to ea ch oth er w ith re sp ect to th e Y ax is
and are coupl ed to each oth er by a w av eguid e 41 (it may a lso be
r eferred to as a thi r d wav egui de ) th at gui des th e po la riz atio n w aves in
15 t he X di rection . T he op enin g 3a of th e ant en na cell 1 c and th e openin g
3a of th e a nt en na c el l 1 d a r e opp os ed to e ach ot he r wit h resp ec t to the
Y axis and are coupled to each other by a waveguide 42 (it may also be
r eferred to as a fourth w av eguid e) th at guid es t he p ola r izati on w aves
i n t he X directio n . Th e cent er o f the w av egui de 41 a nd t he cent er of
20 t he wavegui de 4 2 a r e co upled to e ac h ot he r b y a n e le ct ric fi eld
di rect ion conv ers ion portion 43 t hat gu ide s th e pol arizat ion waves i n
t he Y di rection . T he center of th e el ectri c f iel d d ire cti on c onv ersio n
portion 43 i s co nne cte d t o th e wav egui de 4 4 th at gu i des the
polariza tion waves i n th e X di rectio n .
25 [0035]
F i rst , wave guid ing at th e time of r ec eptio n wil l be des crib ed .
Th e vert i cal pol ari zati on w ave W V in cluded in th e pol ariz atio n
m ul tipl ex ed si gnal th at h as be en pro pa gat ed t o th e a nt enna cel l 1 a
propagat es to o ne end of th e wav egu ide 4 1 . The vertical po l ariz ati on
30 wa ve WV i ncl ud ed i n the po la riz a ti on mu ltipl exed s ignal t ha t has b een
propagat ed to th e a nte nn a cell 1 b p r opagates t o th e ot he r en d of the
waveguide 41. The waveguide 41 is formed in such a way that the
di st an ce from th e c enter o f t he wa ve gu ide 41 t o th e o penin g 3a of th e
13
antenna cel l 1 a becomes e qu al t o the dist anc e f r om t he cent er o f t he
wa vegui de 4 1 to t he o pen in g 3a o f th e a nte nna cell 1 b . Acco r din gl y,
t he ver tic al pol ariz at ion wav es WV th at a re p r opa gat ed from th e
r esp ectiv e ends of th e wa ve gu ide 41 are combin ed i n th e s am e phase at
5 t he cent er of t he w av eguid e 4 1 .
[0 03 6]
The v erti ca l polarizati on wav e W V i nclud ed i n th e po la riz a ti on
m ul tipl ex ed sign al th at h as be en pro pagat ed t o th e a nt enna cel l 1 c
propagat es to o ne end of th e wav egu ide 4 2 . The vertical po l ariz ati on
10 wa ve WV i ncl ud ed i n the po la riz a ti on mu ltip lex ed s ign al th at has b een
propagat ed to th e a nte nn a cell 1 d p r opagates t o th e ot he r en d of the
waveguide 42. The waveguide 42 is provided in such a way that the
di st an ce from th e c ent er o f t he wa ve gu ide 42 t o th e op eni ng 3 a of th e
antenna cel l 1 c becomes eq ual to th e dis tan ce f r om t he cente r o f th e
15 wa vegui de 4 2 to t he op ening 3a o f th e a nte nna cell 1 d . Acco r din gl y,
t he ver tic al pol ariz at ion wav es WV th at a re p r opa gat ed from th e
r esp ectiv e ends of th e wa ve gu ide 42 are combin ed i n th e s am e phase at
t he cen t er of th e w av eguid e 4 2 .
[0 03 7]
20 The elect ri c fi eld dire ct ion con vers ion porti on 43 con ve rt s th e
ve rtical p ol arizati on wav es W V th at a r e prop agat ed t o the res pe ct ive
ends i nt o the Z p ola r izat ion w ave s W Z whose vib r atio n dire ction of the
el ectric fi eld (i . e . , a pol arizatio n pl an e ) is th e Z dire ct ion an d
combi nes th e Z polar iz at ion w av e s W Z aft er th e c onv ersi on at t he
25 ce nt er o f th e el ec t ri c fie ld directi on con ve rsio n p ortio n 43 . In oth er
words, t he electri c fi eld d ire ct ion c onv ersi on po r ti on 4 3 rot at es t h e
vi brati on directi on o f th e el ectri c f ie ld o f t he v ertical po lariz ati on
wa ve WV havi ng a n electri c f i eld th at i s v ibra ted in th e Y di r ec tion to
conv ert th e verti ca l po lariz a ti on w ave W V into t he Z pol arizatio n wa ve
30 W Z havi ng a n electri c f ield t hat i s vib r ate d in th e Z dire ct ion . Th e
combi ned Z p olari zat i on w ave W Z is o ut put t o outsid e ( e.g. , the
t r ansceiv er ) via t he w ave gu id e 44 .
[0 03 8]
14
F i g. 1 1 is a cro ss - s ectio nal v ie w o f t he e le ct ric fi eld dire ctio n
conv ers ion portio n 4 3 on t he Y - Z pl an e. Th e el ect r ic fiel d d ire ctio n
conv ers ion portio n 4 3 ha s a Y(+ ) si de en d co nnecte d to t he u pper
ce nt ral p art o f th e w av egui de 41 a nd a Y ( - ) sid e e nd co nn ected t o t he
5 l ower cen tral par t of t he wav egui de 42.
[0 03 9]
The elect ri c fi eld dire ct ion con vers ion porti on 43 i ncl ude s a
wa vegui de shift p ortio n 43A ( a first wav egu id e shi ft po rti on ), a
wa vegui de shift p ortio n 4 3 B (also call ed a s ec ond wave guid e sh ift
10 portion), a waveguide 43C, and a waveguide 43D. The waveguide 43C
and th e w avegui de 4 3 D are ex tende d in th e Y di r ect i on and are casc ad e
conn ect ed t o each ot he r . A Y ( - ) si de en d part 43E (a fi rst end part ) o f
t he w ave gui de 43C is conn ec ted t o a Y(+ ) sid e en d part 4 3 G (a thi r d
end p art) o f th e wa ve gui de 4 3C .
15 [0040]
The w aveguid e s hi ft porti on 43 A ha s a Y ( -) s ide end p art 43 I (a
fi fth end pa rt) con necte d t o a Y ( +) si de e nd p art 43 F ( a s econd end
pa rt ) o f th e wa ve guid e 43C and a Y ( +) s ide end p art 4 3J (a six th end
pa rt) conn ect ed to th e ce nt er o f th e wa ve gui de 4 1. T he wav egu id e
20 sh i ft p ortion 4 3 A i s a wavegui de ha vin g a st ep -lik e sh ap e in whi ch it s
heigh t in th e Z di r ect i on be co m es l ow er b y t wo s ta ges from t he Y(+)
si de e nd part 4 3J ( th e s ixth end p art ) t ow ard t he Y ( -) s id e en d pa rt 43 I
(t he fifth end p art) .
[0 04 1]
25 The waveguide shift portion 43B has a Y(+) side end part 43K
( a s even th e nd part) con nect ed t o a Y ( -) si de end p art 43 H (a fo urth
end p art) o f th e wa ve gui de 4 3D an d a Y( - ) si de e nd p art 43 L (an ei ght h
end p art) connect ed to th e c ent er o f t he wa ve guide 4 2 . The wave guid e
sh i ft p ortion 4 3 B i s a wavegui de ha ving a st ep -lik e sh ap e in whi ch it s
30 heigh t in th e Z di r ect i on be co m es h igh er b y t wo sta ges fro m the Y(-)
si de e nd part 4 3 L ( th e ei ghth end p art ) t ow ard t he Y(+ ) s ide end p art
43K (t he sev enth end p art) .
[0 04 2]
15
The connection portion between the waveguide 43C and the
wa vegui de 4 3 D ( t he con necti on p orti on b etw een the Y ( -) si de end p art
43E (t he f i rst e nd p art ) o f t he wave gui de 43C an d t he Y(+) sid e en d
pa rt 4 3 G (the t hird e nd p art ) o f t he w av egui de 43 D ) s erv es as an in put
5 and ou tput end th at me diat es th e po la riz ati on w aves in put to t he
el ectric fi eld directio n con versio n po rt io n 43 an d t he pol ariz atio n
wa ves outp ut from th e el ectri c f iel d di r ecti on co nv ersi on po r tion 43 .
[0 04 3]
With re f ere nce to Fig. 1 1, th e elect ri c fi eld d ire ct ion
10 conv ers ion i n t he el ec t ri c fie ld dire ction con vers ion p ortion 4 3 at th e
t i m e of re ce pt ion will be desc r i bed . In Fi g. 1 1 , th e p has e of th e
ve rtical p ol arizati on wav e a t the cen ter of the wav egui de 4 1 becomes
equal to th e p has e of th e v ertic al pol ari z atio n wa ve at t he c ente r o f th e
wa vegui de 4 2. It is as su med h ere th at th e ampl itud e o f th e ve rt i cal
15 polariza tion wave at t he cen te r of th e w avegu id e 41 an d tha t of t he
waveguide 42 are the Y(-) side.
[0 04 4]
The pol ariz ation pla ne (th at i s , th e vib r at ion d ire ct ion of t he
el e ct ric fi eld i s t he Y di r ecti on) of t he v erti cal po lariz atio n w ave on
20 t he Y (+) si de of th e el ec tri c fiel d d ire ct ion con vers ion porti on 43 i s
r ot ated cl ockwis e (right ro tati on) b y 9 0° abo ut th e X ax is in an electric
fi eld di r ec ti on rot ation po rt io n ER1 sh own in Fi g. 11 whil e t he v ertical
polariza tion wave on t he Y ( +) si de o f t he el ect r ic fiel d di r ectio n
conv ers ion portio n 43 is pro pagat ed to th e c enter o f t he el ec tr ic fiel d
25 di rect ion conv ers ion portion 43 v ia th e w av eguid e s hift po rt ion 4 3 A
and th us t he verti c al pol ariz ati on wave o n th e Y ( +) sid e of th e electri c
fi eld di r ec ti on c onv ersio n p ort ion 4 3 i s c onverted t o t he Z po la riz ati on
wave WZ.
[0 04 5]
30 The pol ariz ation pla ne ( t hat i s , t he v i bratio n di rectio n o f the
el ectric fi eld i s t he Y di r ecti on) of t he v erti cal po lariz atio n w ave on
t he Y (- ) sid e of t he ele ctric fi eld di r ecti on co nv ersio n po r tion 43 is
r ot ated cl ockwis e (right ro tati on) b y 9 0° abo ut th e X ax is in an electric
16
fi eld di r ec ti on rot ation po rt io n ER2 sh own i n Fi g. 11 wh i l e th e ve r ti cal
polariza ti on wav e on th e Y( -) s i de o f t he el ect r ic fiel d dire ct ion
conv ers ion portio n 43 is pro pagat ed to th e c enter o f t he el ec tr ic fiel d
di rect ion conv ers ion portion 43 v ia th e wa ve guide shi f t portio n 43 B
5 and th us t he vertic al pol ariz ation wave o n th e Y ( -) si de of t he ele ct ric
fi eld di r ec ti on c onv ersio n p ort ion 4 3 i s c onverted t o t he Z po la riz ati on
wave WZ.
[0 04 6]
Next , wav e gui din g at the t im e o f t r ans miss ion will b e
10 des crib ed . The Z po lariz a t i on w ave W Z f r om outsid e ( e.g., the
t r ansceiv er ) is p r op agat ed to t he e le ct ric fi eld di r ectio n co nve rsion
portion 43 vi a th e wa vegui de 4 4 . Th e el ec t ri c fiel d d ire ct ion
conv ers ion portio n 43 s ep arates an d conv ert s t he Z p olariz a t i on w av e
W Z th at h as b een prop agat ed in t o t he v erti cal po la riz atio n w aves WV
15 t hat ar e in ph as e wi th each ot he r an d gu id es t he vertic al pol ariz ati on
waves WV to the center of the waveguide 41 and the center of the
waveguide 42.
[0 04 7]
With re f ere nce to Fig. 1 1, th e elect ri c fi eld d ire ct ion
20 conv ers ion i n t he ele ct ri c fi eld di rection conv ers ion p o rtio n 43 at th e
t i m e of tra nsm is si on wi ll be d es crib ed . Th e Z po lariz at io n w ave WZ
t hat h as be en prop aga t ed from t he w av eguid e 4 4 to th e cen te r o f th e
el ectric fi eld directio n con versio n po rt io n 43 is s eparate d into tw o
polariza tion waves . The po lariz at i on plan e o f o ne of th e Z
25 polariza tion waves W Z aft er th e separ atio n is r ot at ed cou nte r clockwi s e
(l eft rota tion ) b y 90 ° abou t t he X axis w hil e i t prop aga tes to th e center
of th e w ave guid e 41 vi a t he wa ve gu id e sh ift porti on 4 3 A an d on e of
t he Z pol ari zation wa ves WZ is conv erte d to the v erti cal po la riz ati on
wave WV. The polarization plane of the other one of the Z
30 polariza tion waves W Z aft er th e separ atio n is r ot at ed cou nte r clockwi s e
(l eft rota tion ) b y 90 ° ab ou t th e X axis wh ile it p ro pa gates t o the cent er
of th e w ave guid e 42 vi a t he wa ve gu id e sh ift porti on 4 3 B and th us th e
ot her o ne o f the Z po l ariz ati on wav es W Z i s con ve rt ed to th e v ertic al
17
polariza tion wave W V . As de scri be d ab ove, s inc e the p ola riz ati on
pl an es of the tw o Z p ol ariz ati on waves W Z aft er th e se pa r ati on a r e
r ot ated in the s ame d i rect ion, t he p ha s e of th e v ert ical pol ariz atio n
wave WV at the center of the waveguide 41 becomes equal to the phase
5 of the ve r ti cal p ola riz ati on wa ve W V a t t he cent er of the w ave gu id e 42 .
[0 04 8]
The w aveguid e 4 1 s e pa r ates th e ve rti cal pol arization wav e W V
t hat h as be en pro pagat e d an d gu id es the s ep arat ed waves to th e
r esp ectiv e a nt en na cel l s 1 a and 1b. Th e w av eguid e 4 2 s epa r at es th e
10 ve rtical p ol arizati on wav e W V t hat h as b ee n p r op agat ed an d gui des th e
s eparated wav e s to t he r espectiv e ant enna cel ls 1 c an d 1d.
[0 04 9]
F i g. 1 2 is a di agra m sho win g t he h oriz ontal pol arizatio n wav es
guided by the waveguide portion 5 in the antenna 10. The opening 3b
15 of th e antenna cel l 1 a a nd t he o pe nin g 3 b of the ant enna cel l 1 c a r e
opposed to e ach ot he r w ith respe ct to th e X ax i s and are co upl ed to
ea ch oth er b y a w av eguid e 51 t hat gu ide s the po la riz ati on w ave s in th e
Y d irectio n. T he op eni ng 3b o f th e a nte nna cell 1 b a nd the ope nin g 3 b
of th e antenna cel l 1 d a r e op pose d to each o th er wit h resp ec t to t he X
20 axis a nd are cou pl ed to ea ch oth er by a wa ve guid e 52 t hat gui de s the
polariza tion wave s i n th e Y d irecti on . The cent er of t he wav egu id e 51
and th e c ent er o f t he w av eguid e 5 2 a r e cou pled to each o the r b y a
wa vegui de 5 3 th at guide s th e pol arizat ion wave s i n th e X di r ecti on . A
wa vegui de 5 4 th at guides t he pol arizat ion wave s i n th e Y di r ecti on is
25 conn ect ed t o th e c ent er o f t he wa ve guid e 5 3 .
[0 05 0]
F i rst , wave guid ing at th e time of r ec eptio n wil l be des crib ed .
Th e horiz ontal po l ari zatio n wa ve WH i ncl uded i n the po lariz a t i on
m ul tipl ex ed si gnal th at h as be en pro pa gat ed t o th e a nt enna cel l 1 a
30 propagat es to t he ope ni ng 3 b of th e po la riz ati on w ave
s eparation /comb inat ion po rt ion 3 o f the an ten na cell 1 a . Then th e
vi brati on directi on o f t he el ect r i c field (th at i s, th e p ola riz ati on pl ane )
of th e ho r izont al p ol ariz ati on wave WH is rot at ed b y 90 ° ab out t he Y
18
axis w hi le th e hori zon tal pol ariz at i on wave W H prop agat es fro m the
openi ng 3 b t o t he wa vegui de 5 1 and th us t he ho riz o nt al pol ariz at ion
wave WH becomes the Z polarization wave WZ. The horizontal
polariza tion wave WH in clud ed i n th e pol ariz atio n m ultip lex ed s ign al
5 t hat h as be en prop aga t ed to the an te nn a cell 1 c p r op agates t o t he
openi ng 3 b of th e po la riz ati on w av e sep ara ti on/ comb i natio n po rt ion 3
of th e a nte nna cell 1 c . Afte r th at , t he v ibra ti on di r ec ti on of th e
el ectric fi eld (t hat i s, th e p ola rizat ion plane ) o f t he ho r izo nt al
polariza tion wave WH is rot ated b y 90 ° abou t t he Y axis whil e th e
10 horizo nta l polari z ation wav e W H p ropagat es fr om the ope nin g 3 b to th e
waveguide 51 and thus the horizontal polarization wave WH becomes
the Z polarization wave WZ. The waveguide 51 is provided in such a
wa y th at th e dista nc e from t he cent er of t he wa ve guide 5 1 t o the
openi ng 3 b of th e a nte nn a cell 1 a b ec om es eq ual to th e distan ce f r om
15 t he cent er of th e w av eguid e 5 1 to t he op en ing 3b o f t he ante nn a cell 1 c .
Ac cordin gl y, t he Z pol ariz atio n wa ves WZ th at p rop aga t e from th e
r esp ectiv e ends of th e wa ve gu ide 51 are combin ed i n th e s am e phase at
t he cent e r of th e w av eguid e 5 1 .
[0 05 1]
20 The horiz ontal pol ari zatio n wa ve WH i ncl uded i n the
polariza tion mul tipl exed si gna l th at h as b een p r op agat ed to t he ant enn a
cell 1 b p rop aga te s to th e op enin g 3b o f th e pol ariz atio n wa ve
s eparation /comb inat ion po rt ion 3 o f th e ant enn a c el l 1b . Aft er tha t ,
t he v i brati on di rectio n of t he ele ct ric fi eld (t hat i s, t he po la riz a ti on
25 pl an e ) o f th e horiz ont al pol ariz atio n wave W H is rot at ed b y 90 ° ab out
t he Y ax is whil e th e horiz ont al polariz a ti on w av e W H p ro pa gat es from
t he op eni n g 3b t o th e wav egu id e 5 2 and t hus t he h orizon tal
polarization wave WH becomes the Z polarization wave WZ. The
horizo nta l polari z ation wav e W H i ncl ud ed i n th e pol arizatio n
30 m ul tipl ex ed si gnal th at h as be en pro pa gat ed t o th e a nt enna cel l 1 d
propagat es to t h e op eni ng 3 b o f th e po la riz ati on w ave
s eparation /comb inat ion po rt ion 3 o f the ant enn a cel l 1d . Aft er tha t ,
t he v i brati on directio n of t he ele ctric fi eld (t hat i s , t he po la riz a ti on
19
pl an e ) o f th e horiz ont al pol ariz atio n wave W H is r ota t ed b y 9 0° ab out
t he Y axis whi le th e ho riz ont al pol arizatio n wa ve WH prop agat es f r om
t he op eni ng 3b to the wavegui de 52 and th e h oriz ont al p ola r iz at ion
wave WH becomes the Z polarization wave WZ. The waveguide 52 is
5 provid ed in s uch a wa y t hat t he dist an ce from th e c en ter o f t he
waveguide 52 to the opening 3b of the antenna cell 1b becomes equal
t o t he di st ance from t he cen te r of th e w ave guid e 52 to th e o penin g 3b
of th e antenna cel l 1 d . Ac cordin gl y, t he Z p olar iz at ion w av es W Z t hat
propagat e fro m the r esp ect ive ends of the wav egu i de 52 are co mbined
10 i n t he sam e phas e at th e cent er of t he wav egui de 52.
[0 05 2]
The wave gui de 5 2 is p rov id ed in s uch a w a y t hat the di st an ce
f r om t he c enter of the wav egui de 5 3 t o the cent er of t he wav egu id e 51
be co mes e qual to t he distanc e fro m t h e ce nt er o f th e wa ve gui de 5 1 t o
15 t he cent er of t he w av eguid e 5 1 . Ac co rdin gl y, the Z po lariz at io n wa ve s
WZ that are propagated from the respective ends of the waveguide 53
are co mbin ed in th e s ame p hase at t he cen t er of th e w av eguid e 5 3 . Th e
combi ned Z p ol ari zat ion wave W Z is o ut put t o out sid e ( e.g., the
t r ansceiv er ) via t he w ave gu id e 54 .
20 [0053]
Next , wa ve gui din g at the t i m e o f t r ans miss ion will b e
des crib ed . Th e Z po lariz a t i on w ave W Z is propagat ed from out si de
( e.g. , th e transcei ve r ) to th e c ent er o f th e w av egu id e 51 and t he cen t er
of the waveguide 52 via the waveguides 54 and 53. The waveguide 51
25 s eparates the Z polar iz at ion w av e W Z th at has b ee n propagat ed . The Z
polariza tion waves W Z aft er th e separ atio n are p r opa gated to the
r esp ectiv e o penin g s 3b o f th e ant enna cel ls 1 a and 1 c. Aft er tha t , the
vi brati on directi on o f th e el ectri c f ie ld ( i . e . , th e pol ari zat ion p l an e ) of
t he Z pol ari zation wa ve s W Z is rot at ed b y 9 0° ab out th e Y ax i s whil e
30 the Z polarization waves WZ propagate from the waveguide 51 to the
openings 3b and thus the Z polarization wave s WZ become the
horizo nta l polari z ation wav e s W H . Th e w av eguid e 5 2 s epa r at es th e Z
polariza tion wave W Z th at h as be en prop agat ed . Th e Z p olariz a t i on
20
wa ves W Z aft er th e s ep aratio n a r e p ropa gated to th e r espe ctiv e
openi ngs 3b of th e an t enn a c ells 1 b and 1d . A ft er t hat , th e vib r atio n
di rect ion o f th e el ectri c f iel d (t hat i s , t he pol ariz atio n pl an e ) o f th e Z
polariza tion wave s W Z i s ro tated b y 90 ° abou t t he Y axi s w hil e t he Z
5 polarization waves WZ propagate from the waveguide 52 to the
openings 3b and thus the Z polarization wave s WZ become the
horizo nta l polari z ation wav e s W H .
[0 05 4]
As d es crib ed ab ove , th e b endi ng portio n i s p r es ent in th e
10 conn ect ion po rt ion b et ween t he o peni ng 3b o n t he b ottom surfa ce o f
t he p ol arizat ion wave se parati on/ co m bi nation portion 3 and th e
wa vegui de p ort ion 5 . A cc ording t o this st r uct ure , th e p rop aga tio n
di rect ion of t he horiz ont al pol ariz ati on wav e W H and t hat of th e Z
polariza tion wave W Z are chan ged , wi th t he d ire ct ion p erpe ndi cular t o
15 t he p ol arizat ion pl an e s ervin g as a rotati on ax i s , wh ere by th e
polariza tion pl an e of t he ho r izo nt al p ola riz ati on w av e WH an d t hat o f
t he Z pol ari zation wa ve WZ are rot at ed b y 9 0° . As a r esu lt , th e
el ectric fi eld di r ec ti on co nv ers io n can b e mut uall y pe r f orm ed b etw een
the horizontal polarization wave WH and the Z polarization wave WZ.
20 [0055]
In a sim ila r wa y, r ega rd ing th e ve rt i cal pol ari zation wa ve W V
as well , i t m a y be poss ibl e to perfo r m th e elect ri c fi eld di r ec t i on
conv ers ion between the ve rtical p ola riz ati on w ave W V and t he Z
polariza tion wave W Z b y con necti ng the p ol ariz at ion wave
25 s eparation /comb inat ion po rt ion 3 and th e w av egu id e portio n throu gh
t he op eni ng provi de d on the bott om su r f ac e o f th e pol arizatio n wa ve
s eparation /comb inat ion po rt ion 3 . In this cas e, ho we ver, the t wo
di fferent w aveguid e portio n s ne ed to b e arra nged i n th e sam e la yer .
Wh en t he s t ru ctu r e i n whi ch t he pol ariz atio n wa ves t hat hav e been
30 guided are com bin ed in ph ase wit h ea ch oth er is provid ed in th e st at e
i n wh i ch th e tw o d iff ere nt wav egu id e p ortio ns are a r r anged i n th e sam e
l a yer , i t b ecom es di ffi cul t t o arra nge th e wa ve guide s of the res pe cti ve
wa vegui de p ort ion s in such a w a y t hat t he y do not i nt erfer e wit h o ne
21
anoth er . Fu rth er, whe n t he w av egui des are a r ran ged i n such a w ay th at
t he y do not int erfe r e with o ne a noth er , the structure becomes
compl icate d, wh ic h ca us es an in creas e in t he n umb er of m anu f actu ring
processe s an d an in cre ase i n th e th ickne ss of the pla na r an ten na .
5 [0056]
On the o th er h and , i n this ex empl ar y em bodim ent , t he
wa vegui de p ort ion 4 t hrough whi ch th e ve rt ic al p ol ar iz at ion wav es
pas s has the elect r ic fi el d dire ction c onv ersio n fun ct ion (t he electri c
fi eld di rection conv ers ion p ort ion 4 3 ) , w he r eby t he w aveguid e portio n
10 t hat r eceive s or o ut put s the v ert i cal po la riz ati on w ave s and t he
wa vegui de p ort ion t hat r ec ei ves or outpu ts t he ho riz on tal p ola rizati on
wa ves c an be a r r an ged in l a yers diffe r ent from e ach o th er . Furth er, th e
i nt rodu cti on of the ele ctric fi eld di r ectio n co nv ersio n po rti on p rev ents
an incr ea s e i n t he thi ck nes s o f t he waveguid e l a yer inc l udin g t he
15 el ectric fi eld directio n con versio n po rt io n . It is t herefo r e pos si ble t o
provid e a hi gh - gai n an d thin po la riz ed w av e sh ared pla na r ant en na that
us es th e w av eguid e s.
[0 05 7]
Other Exemplary Embodiments
20 Note t hat t he pres ent inv ent ion is no t l im ited to th e
aforementioned exemplary embodiments and may be changed as
appro pr iat e with ou t departin g f r om t he spi rit o f t he pres ent inv enti on .
F or ex ampl e, whil e th e aforem ent ioned h orn ant enn a p orti on 2 in clud es
t he recta ngular ope nin g, t his is me r el y an ex ampl e . A ho r n ant enn a
25 portion hav in g an ope ni ng w hose s hape is oth er tha n t he r ect an gul ar
sh ape ( e. g. , ci rcular sh ape ) ma y be emplo yed . Furth er, th e ho rn
antenna st r uctu r e ma y be repl ac ed by, fo r ex ampl e, a s lot st ruct ure
su ch as a cros s -shap ed slot .
[0 05 8]
30 Needless to say, the number of antennas 10 and the number of
antenna cel ls 1 sta ted ab ov e are merel y ex amp les and t he num be r of
compo nents in t he pla nar ant en na may b e i nc r eas ed o r d ecr ease d as
appro pr iat e .
22
[0 05 9]
Al t ho ugh t he prese nt i nventi on has b een des c r ib ed a bove with
r eferenc e t o ex empl ar y emb odim en t s , the pres ent i nv e n t i on i s n ot
1 i m i t ed to the abo ve ex empl ar y em bod ime nt s . T he con figu r a t i on and
5 details of t he p r es ent inv e n t i on can be modi fied i n v a r io us m ann e rs
which ca n be un derst ood b y th ose sk i l l e d i n the art wit hin th e s cop e of
t he inv ent i o n .
[ 0060]
This appli c a t i on is based upo n and clai ms th e be ne fit o f p r i o r i t y
10 f r om J ap an es e Pate nt Ap p l i cat ion No. 201 4 -166 0 0 7 , fi le d o n August 18,
2014, th e dis c lo su r e of whi ch is i nco r pora t ed h er ei n in its entiret y b y
r eferenc e.
Reference Signs List
[0 06 1]
15 1, 1a-1d ANTENNA CELL
2 HORN ANTENNA PORTION
3 POLARIZATION WAVE SEPARATION/COMBINATION
PORTION
3a, 3b OPENING
20 4, 5 WAVEGUIDE PORTION
10 ANTENNA
4 1 , 42, 43C, 43D, 44, 51-54 WAVEGUIDE
43 ELECTRIC FIELD DIRECTION CONVERSION PORTION
43A, 43B WAVEGUIDE SHIFT PORTION
25 100 PLANAR ANTENNA
WH HORIZONTAL POLARIZATION WAVE
WV VERTICAL POLARIZATION WAVE

WE CLAIM:
1. An electric field direction conversion structure comprising:
a first waveguide configured to guide a first radio wave whose
e l e c t r i c field is vibrated in a first direction along a second direction
that is vertical to the first direction between a first end part and a
second end part;
a second waveguide configured to guide the first radio wave
along the second direction between a third end part and a fourth end
part, the second waveguide being cascade connected to the first
waveguide by a connection of the first end part and the third end part;
an input and output end configured to multiplex the first radio
wave from the first waveguide and the first radio wave from the second
waveguide and outputs the multiplexed radio wave, and outputs the
first radio wave branched off from a radio wave from outside to the
first and second waveguides at a connection portion between the first
end part and the third end part;
a first waveguide shift portion having a fifth end part connected
to the second end part of the first waveguide and a sixth end part that
is shifted from the fifth end part in the first direction, a second radio
wave having an electric field vibrated in the second direction being
input or output to or from the sixth end part along the second
direction; and
a second waveguide shift portion having a seventh end part
connected to the fourth end part of the second waveguide and an eighth
end part that is shifted from the seventh end part in the first direction
and in a direction opposite to the sixth end part, the second radio wave
having an electric field vibrated in the second direction being input or
output to or from the eighth end part along the second direction,
wherein:
the vibration direction of an electric field of a radio wave
passing through the sixth end part of the first waveguide shift portion
is rotated by 90° about a third direction that is vertical to the first and
second directions, and
the vibration direction of an electric field of a radio wave
passing through the eighth end part of the second waveguide shift
portion is rotated by 90° about the third direction in a direction the
same as the rotational direction in the sixth end part.
2. The electric field direction conversion structure according to
Claim 1, wherein:
the first waveguide shift portion is formed of a curved
waveguide that connects the fifth end part and the sixth end part, and
the second waveguide shift portion is formed of a curved
waveguide that connects the seventh end part and the eighth end part.
3. The electric field direction conversion structure according to
Claim 2, wherein the center axis of the waveguide that constitutes the
first waveguide shift portion and the second waveguide shift portion is
the second direction, and the waveguide has a step-like shape and is
shifted in a step-like manner along the first direction.
4. The electric field direction conversion structure according to
Claim 2 or 3, wherein the distance between the input and output end
and the sixth end part is equal to the distance between the input and
output end and the eighth end part.
5. A planar antenna comprising:
first to fourth antenna elements that are arranged in a grid on a
plane that is vertical to the first direction, each of the first to fourth
antenna elements combining a p l u r a l i t y of polarization waves and
t r a n s m i t t i n g a polarization multiplexed signal or separating a
polarization multiplexed signal that has been received into a plurality
of polarization waves;
25
a first waveguide part configured to output the second radio
wave to the first to fourth antenna elements or receives the second
radio wave that has been separated by the first to fourth antenna
elements; and
a second waveguide part configured to output a third radio wave
having an electric field whose vibration direction is vertical to the
vibration direction of the electric field of the first and second radio
waves to the first to fourth antenna elements or receives the third radio
wave separated by the first to fourth antenna elements,
wherein the first waveguide part comprises:
the electric field direction conversion structure
according to any one of Claims 2 to 4;
a third waveguide having one end connected to the first
antenna element and another end connected to the second antenna
element, the center of the third waveguide being connected to the sixth
end part, and the third waveguide extending in the third direction; and
a fourth waveguide having one end connected to the third
antenna element and another end connected to the fourth antenna
element, the center of the fourth waveguide being connected to the
eighth end part, and the fourth waveguide extending in the third
direction.
6. The planar antenna according to Claim 5, wherein the
distance between the center of the third waveguide and the first
antenna element, the distance between the center of the third
waveguide and the second antenna element, the distance between the
center of the fourth waveguide and the third antenna element, and the
distance between the center of the fourth waveguide and the fourth
antenna element are equal to one another.
7. The planar antenna according to Claim 5 or 6, wherein:
the first to fourth antenna elements each comprise:
26
a polarization wave separation/combination portion
configured to separate the second radio wave and the third radio wave
included in the polarization multiplexed signal or combines the second
radio wave and the third radio wave into the polarization multiplexed
signal;
a horn antenna portion configured to transmit the
polarization multiplexed signal from the polarization wave
separation/combination portion or transmits the polarization
multiplexed signal that has been received to the polarization wave
separation/combination portion, and
the polarization wave separation/combination portion receives
or outputs the second radio wave through an opening on a plane
vertical to the third direction and receives or outputs the third radio
wave through an opening on a bottom surface vertical to the first
direction.
8. The planar antenna according to Claim 7, wherein:
the second waveguide part is connected to the opening on the
bottom surface of the polarization wave separation/combination portion
of each of the first to fourth antenna elements, and
the second waveguide part converts the third radio wave from
the opening on the bottom surface of the polarization wave
separation/combination portion of each of the first to fourth antenna
elements into the first radio wave, combines the resulting radio waves
in phase with each other, and outputs the combined radio wave or
separates the first radio wave input from outside to convert the first
radio wave into the third radio wave and guides the third radio wave
after the conversion to the opening on the bottom surface of the
polarization wave separation/combination portion of each of the first
to fourth antenna elements in the same phase.
27
9. The planar antenna according to any one of Claims 5 to 8,
wherein the first waveguide part and the second waveguide part are
formed in different layers laminated to each other in the first direction.
10. A planar antenna comprising:
a plurality of antenna elements arranged on a first plane;
a first waveguide part configured to receive or outputs a first
radio wave from or to the plurality of antenna elements, the first radio
wave being used for orthogonal polarization transmission; and
a second waveguide part configured to receive or outputs a
second radio wave whose polarization plane is perpendicular to the
polarization plane of the first radio wave from or to the plurality of
antenna elements,
wherein the first waveguide part and the second waveguide part
are laminated to each other substantially parallel to the first plane.
11. The planar antenna according to Claim 10, wherein:
the first waveguide part comprises an electric field direction
conversion portion having a first end part connected to a first antenna
element, a second end part connected to a second antenna element, and
an input and output end through which a third radio wave having a
polarization plane perpendicular to the polarization plane of the first
radio wave is input or output,
the polarization plane of the third radio wave is rotated in such
a way that the polarization plane of the third radio wave matches the
polarization plane of the first radio wave while the third radio wave is
guided from the input and output end to the first and second end parts,
and
the polarization plane of the first radio wave is rotated in such
a way that the polarization plane of the first radio wave matches the
polarization plane of the third radio wave while the first radio wave is
guided from the first and second end parts to the input and output end.
28
12. The planar antenna according to Claim 11, wherein:
the electric field direction conversion portion is a waveguide
that couples the first end part and the second end part, and
the input and output end is provided at the center of the
waveguide that is provided between the first end part and the second
end part.