1. A wireless signal t ransmitting antenna comprising: signal emitting means having N number of antenna elements (where N is an integer satis f yin g N≥2 ) equ all y sp aced on a cir cumf er 5 ence of circle; and signal distribution means for generating, from an input first signal, N number of second signals having a phase difference from one another, and output ting the N number of second signals to the N number of antenna elements, respectively, so that a spiral beam with an equiphase surface inclined spirally is 10 output from the signal emit ting means.

2. The wireless signal transmitting antenna according to Claim 1, wherein the signal distribut ion means distributes signals so that second signals having a specified phase difference, the phase difference increasing in incremental steps in 15 the circumferential direction, are input to the antenna elements adjacent in the signal emitting means.

3. The wireless signal transmitting antenna according to Claim 2, wherein wh en M numb er of di ff erent fir st si gn als (wh er e M is an int eger s atis f yi n g M≤N) 20 are input, the signal distribution means generates and outputs the second signals to the N number of antenna elements, respect ively, so that M number of different spiral beams are output from the signal emitting means.

4. The wireless signal transmitting antenna according to Claim 3, further 25 comprising: another signal distribution means for receiving M numb er of different other first signals orthogonal to the first signal , and outputting N number of other second signals orthogonal to the second signals so that orthogonally polarized waves of the spiral beam are formed by the signal emitting means. 30

5. The wireless signal transmitting antenna according to any one of Claims 1 to 4, wherein a diameter of the circumference where the antenna elements are placed is changed based on a signal transmitting and receiving distance. 20

6. A wireless signal receiving antenna comprising: signal receiving means having X number of antenna elements (where X is an integer satisfying X≥2 ) equ all y sp aced on a cir cumf er ence o f cir cl e; an d signal synthesis means for receiving, as X number of second signals, spiral beams with equiphase surfaces inclined spirally received by the 5 signal receiving means from the N number of antenna elements, respectively, adding a phase difference to each of the X number of second signals, synthesizing a first signal therefrom, and output ting the first signal . 10 7. The wireless signal receiving antenna according to Claim 6, wherein the signal synthesis means adds a specified phase difference to the X number of second signals input from the antenna elements adjacent in the signal receiving means so that the phase difference decreases in decremental steps in the circumferential direction. 15

8. The wireless signal receiving antenna according to Claim 7, wherein when the signal receiving means receives Y number of different spiral beams (wh er e Y i s an in teger s atis f yi n g Y≤X), t h e si gn al s yn th esis means r ecei ves s econd signals from the N number of antenna elements, respectively, and generates Y 20 number of different first signals.

9. The wireless signal receiving antenna according to Claim 8, further comprising: another signal synthesis means for outputt ing an another first signal 25 orthogonal to the first signal when the signal receiving means receives orthogonal ly polarized waves of the spiral beams.

10. The wireless signal receiving antenna according to any one of Claims 6 to 9, wherein a diameter of the circumference where the antenna elements are 30 placed is changed based on a signal transmitting and receiving distance.

11. A wireless signal transmitting system comprising: signal emitting means for outputting a transmission signal by N number of ant enn a el ements (wh er e N i s an i nteger satisf yi n g N≥ 2); and 21 signal distribution means for generating, from an input first signal, N number of second signals having a phase difference from one another, and output ting the N number of second signals to the N number of antenna elements, respectively, wherein the N number of antenna elements are equally spaced 5 on a circumference of circle.

12. The wireless signal transmit ting system according to Claim 11, wherein when M number of different first signals (where M is an integer satisfying 10 M≤N) are input , the signal distribution means generates and outputs the second signals to the N number of antenna elements, respectively, so that M number of different transmission signals are output from the signal emitting means.

13. The wireless signal transmit ting system according to Claim 11 or 12, 15 wherein the signal emitting means outputs an OAM transmission signal.

14. The wireless signal transmit ting system according to Claim 11 or 12, wherein the signal emitting means outputs a transmission sign al with an equiphase surface incl ined spirally. 20

15. A wireless signal transmitting method comprising: generat ing, from an input first signal, N number of second signals having a phase difference from one another; and output ting the N number of second s ignals to N number of antenna 25 elements, respectively, so that a spiral beam with an equiphase surface incl ined spirally is output from a signal emi tting means having the N number of antenna el ements (wh er e N is an int eger s atis f yi n g N≥2 ) eq ual l y sp aced on a circumference of circle. 30 16. The wireless signal transmit ting method according to Claim 15, wherein signals are distributed so that second signals having a specified phase difference, the phase difference increasing in incremental steps in the circumferential direction, are input to the antenna elements adjacent in the signal emitting means. 22

17. The wireless signal transmit ting method according to Claim 16, wherein when M number of different first signals (where M is an integer satis f yi n g M≤N) are i nput, the second signals are generated and output to the N number of antenna elements, respectively, so that M number of 5 different spiral beams are output from the signal emitting means.

18. The wireless signal transmit ting method according to Claim 17, comprising: 10 receiving M number of different other first signals orthogonal to the first signal and outputting N number of other second signals orthogonal to the second signals so that orthogonal ly polarized waves of the spiral beam are formed by the signal emitting means. 15 19. The wireless signal transmit ting method according to any one of Claims 15 to 18, wherein a diameter of the circumference where the antenna elements are placed is changed based on a signal transmitt ing and receiving distance. 20 20. A wireless signal receiving method comprising: receiving, as X number of second signals, spiral beams wi th equiphase surfaces inclined spirally received by a signal receiving means having X number of ant enn a el ements (wh er e X i s an i nteger satisf yi n g X≥ 2) e qually spaced on a circumference of circle from the N number of antenna elements, respectively, 25 adding a phase difference to each of the X number of second signals, synthesizing a first signal therefrom, and outputting the first signal.

21. The wireless signal receiving method according to Claim 20, wherein a specified phase difference is added to the X number of second signals input from 30 the antenna elements adjacent in the signal receiving means so that the phase difference decreases in decremental steps in the circumferential direction.

22. The wireless signal receiving method according to Claim 21, wherein wh en Y n umb er o f di ff erent s pir al beams (wh er e Y is an in teger sati sf yi n g Y≤X) 23 are received by the signal receiving means, second signals are inpu t from the N number of antenna elements, respectively, and Y number of different first signals are generated.

23. The wireless signal receiving method according 5 to Claim 22, comprising: output ting another first signal orthogonal to the first signal when orthogonal ly polarized waves of the spiral beams are received by the signal receiving means. 10

24. The wireless signal receiving method according to any one of Claims 20 to 23, wherein a diameter of the circumference where the antenna elements are placed is changed based on a signal transmitting and receiving distance.

DESCRIPTION
WIRELESS SIGNAL TRANSMITTING ANTENNA, WIRELESS SIGNAL
RECEIVING ANTENNA, WIRELESS SIGNAL TRANSMITTING SYSTEM,
WIRELESS SIGNAL TRANSMITTING METHOD, AND WIRELESS SIGNAL
5 RECEIVING METHOD
Technical Field
[0001]
The present invention relates to a wireless signal transmitting antenna, a
wireless signal receiving antenna, a wireless signal transmitting system, a wireless
10 signal transmitt ing method, and a wireless signal receiving method that form
signals into spiral beams and wirelessly communicate th em.
Background Art
[0002]
Communications in the range of frequencies currently used for wireless
15 communicat ions are approaching the limit . To solve this problem, the
communicat ion technology that adds the orbital angular momentum (OAM) to
wireless signals to form signals into spiral beams and transmits and receives them
is under study. The signals which are formed into spiral beams have the
characteristics that the equiphase surface is twisted in a spiral form. By changing
20 the spiral pitch of the equiphase surface of spiral beams, it is possible to form
infinite orthogonal mode signals. Therefore, by use of spiral beams for wireless
communicat ions, it is possible to perform multiple communicat ions over the same
frequency, thereby achieving higher -speed and higher -capacity communications.
[0003]
25 The study on communications using signals in spiral beams to which the
orbital angular momentum is added is disclosed in Non Patent Li terature 1 and Non
Patent Literature 2, for example. Non Patent Literature 1 discloses formation of a
spiral beam where the orbital angular momentum is added to a signal by use of an
OAM antenna 50 having a reflecting uni t 51 where a cut is made in a part of a
30 parabolic antenna as shown in Fig. 16. Non Patent Literature 2 disclose s the
experiment showing that, as a result of forming a spiral beam using the OAM
antenna 50 and transmitting a signal , this signal can be received at a receiving
point located at a long distance.
Citation List
3
Non Patent Literature
[0004]
NPL1: "BR witnesses experiment on Radio Orbital Angular Momentum
(OAM) with potential for drastic improvement in spectrum efficiency", ITU,
Internet (URL: http://www.itu.int/en/ITU-R/trends/OAM/5 Pages/default.aspx)
NPL2: Fabrizio Tamburini , and five others, New Journal of Physics
2012/3/1 "Encoding many channels on the same frequency through radio vorticity:
first experimental test", Internet (URL:
http://iopscience.iop.org/1367-2630/14/3/033001)
10 Summary of Invention
Technical Problem
[0005]
According to the OAM antenna 50 disclosed in Non Patent Literature 1 and
Non Patent Literature 2, it is possible to form a spiral beam and transmit a signal .
15 For actual high-speed and high-capacity communicat ions, multiplexing of a
plurality of spiral beams with different spiral pi tches is required. However,
because the OAM antenna 50 physically forms a spiral beam by using the
reflecting unit 51 where a cut is made in a part of a parabolic antenna, it is not
possible to change the spiral pitch of the spiral beam. Thus, the OAM an tenna
20 disclosed in Non Patent Literature 1 and Non Patent Literature 2 has a problem that
it is not possible to form a plurality of spiral beams with different spiral pitches.
[0006]
An exemplary object of the present invention is to provide a wireless
signal transmitt ing antenna, a wireless signal receiving antenna, a wireless signal
25 transmitting system, a wireless signal transmitting method, and a wireless signal
receiving method that can, for wireless communicat ions, form a signal into a spiral
beam and change the spiral pitch of the signal, and further can use a plural ity of
spiral beams wi th different spiral pitches simultaneously for wireless
communicat ions.
30 Solution to Problem
[0007]
One exemplary aspect of the present invention is a wireless signal
transmitting antenna including a signal emitting means having N number of
antenna elements (where N is an i nteger satisf yi n g N≥ 2) eq uall y sp aced on a
4
circumference of circle; and a signal distribution means for generating, from an
input first signal , N number of second signals having a phase difference from one
another and outputting the N number of second signals to the N number of antenna
elements, respectively, so that a spiral beam with an equiphase surface incl ined
spirally is output from the signal 5 emitting means.
[0008]
One exemplary aspect of the present invention is a wireless signal
receiving antenna including a signal receiving means having X number of antenna
elements (where X is an integer satisfying X≥2 ) eq ual l y sp aced on a ci r cumfer en ce
10 of circle; and a signal synthesis means for receiving, as X number of second
signals, spiral beams with equiphase surfaces inclined spirally received by the
signal receiving means from the N number of antenna elements, respectively,
adding a phase difference to each of the X number of second signals, and
synthesizing and outputting a first signal.
15 [0009]
One exemplary aspect of the present invention is a wireless signal
transmitting method including generating, from an input first signal , N number of
second signals having a phase difference from one another; and outputting the N
number of second signals to N number of antenna elements, respectively, so that a
20 spiral beam with an equiphase surface incl ined spirally is ou tput from a signal
emitting means having the N number of antenna elements (where N is an integer
satis f yi n g N≥2 ) eq ual l y sp aced o n a cir cumfer en ce o f cir cl e.
[0010]
One exemplary aspect of the present invention is a wireless signal
25 receiving method including receiving, as X number of second signals, a spiral
beam with equiphase surface received by a signal receiving means having X
numb er o f ant enn a el ements (wh er e X i s an int eger s atis f yi n g X≥2 ) equ all y sp aced
on a circumference of circle from the N number of antenna elements, respect ively,
adding a phase difference to each of the X number of second signals, synthesizing
30 a first signal therefrom and outputting the first signal.
[0011]
One exemplary aspect of the present invention is a wireless signal
transmitting system including a signal emi tting means for outputting a
transmission signal by N number of antenna elements (where N is an integer
5
satis f yi n g N≥2) ; an d a si gn al di stri buti on means f or gen eratin g, f rom an in put fi rst
signal, N number of second signals having a phase difference from one another,
and outputting the N number of second signals to the N number of antenna
elements, respectively, wherein the N number of antenna elements are equal ly
spaced on a circumference 5 of circle.
Advantageous Effects of Invention
[0012]
According to the wireless signal transmitt ing antenna, the wireless signal
receiving antenna, the wireless signal transmitting system, the wireless signal
10 transmitting method and the wireless signal receiving method according to the
exemplary aspects of the present invention, it is possible to form a signal into a
spiral beam and change the spiral pitch of the signal for wireless communications,
and further to use a plurality of spiral beams with different spiral pitches
simultaneously for wireless communications.
15 Brief Description of Drawings
[0013]
Fig. 1 is a view showing the structure of a wireless transmitting antenna
according to a first exemplary embodiment.
Fig. 2 is a view showing the principle of a signal distribution circui t using
20 a But ler matrix feeding circuit.
Fig. 3 is a view showing the way a spiral beam is formed by a signal
emitting means A.
Fig. 4 is a view showing the principle of a signal distribution circuit using
a But ler matrix feeding circuit with a plurality of input ports.
25 Fig. 5 is a flowchart showing a process of forming a spiral beam by the
wireless transmitting antenna.
Fig. 6 is a view showing the structure of a signal distribution circuit
included in a wireless transmitting antenna according to a sec ond exemplary
embodiment.
30 Fig. 7 is a view showing the state where M number of different first
signals are input to the wireless transmitting antenna.
Fig. 8 is a flowchart showing a process of forming M number of different
spiral beams by the wireless t ransmitting antenna.
Fig. 9 is a view showing the structure of a wireless receiving antenna
6
according to a third exemplary embodiment.
Fig. 10 is a flowchart showing a process of receiving a spiral beam by the
wireless receiving antenna.
Fig. 11 is a view showing the structure of a signal synthesis circuit
included in a wireless receiving antenna according to 5 a fourth exemplary
embodiment.
Fig. 12 is a flowchart showing a process of receiving M number of
different spiral beams by the wireless receiving antenna.
Fig. 13 is a view showing the structure of a wireless transmitting and
10 receiving system according to a fifth exemplary embodiment.
Fig. 14 is a view showing a modified example of a wireless transmitting
antenna according to a seventh exemplary embodiment.
Fig. 15 is a view showing the structure of a wireless transmitting antenna
according to an eighth exemplary embodiment .
15 Fig. 16 is a view showing an OAM antenna according to related art.
Description of Embodiments
[0014]
First exemplary embodiment
Exemplary embodiments of the present invention are described hereinafter
20 with reference to the drawings.
[0015]
[First exemplary embodiment]
As shown in Fig. 1, a wireless transmitting antenna (wireless transmitting
system) 10 includes a signal emit ting means A having N number of antenna
25 elements A1, A2, …, AN (where N is an integer of 2 or more) that are equally
spaced on the circumference of circle, a signal input port (signal input means) C
fo r in putti n g fi rst s i gnals S1, …, SM, an d a si gn al d ist r ibution circuit (signal
distri buti on means ) B fo r dist ribut in g th e i nput fi rst si gn als S1, …, SM to N
number of second signals S2 with equal power and outputs them to the antenna
30 elements A1, A2, …, AN, respectively. By this structure, the wireless
transmitting antenna 10 can form and tr an smit, fr om t he inp ut f irst si gn als S1, …,
SM, a t ransmiss ion si gnal in a spi r al b eam b y th e an tenn a elements A1 , A2 , …,
AN.
[0016]
7
The ant enn a el ements A1, …, AN ar e equ al l y sp aced o n th e ci r cumf er en ce
of circle with a diameter of 30cm, for example. Those plurali ty of antenna
el ements A1, …, AN con stitut e t he si gnal emitti n g means A. The si gnal emittin g
means A corresponds to the reflecting unit 51, which is a parabolic antenna with a
cut shown in Fig. 16. A parabolic antenna may be used as each 5 of the antenna
el ements A1, …, AN, for example. The signal emitting means A and the signal
distribution circuit B are connected through a signal waveguide D. The signal
waveguid e D has N n umber of si gnal lin es D1, …, DN with e qual length. The
si gn al li nes D1, …, DN co nn ect N numb er o f s i gn al emitt in g p orts B1, …, BN of
10 the signal distribution circuit B and the antenna elements A1, …, AN. Coaxial
cabl es o r wav egui des ma y b e u sed as t he s ignal lin es D1, …, DN.
[0017]
The signal distribution circuit B distributes the first signal S that is input
fr om an y o f th e plu ralit y o f s i gn al i nput p orts C1, …, CM t o N numb er o f s econ d
15 signals G1, …, GN with equal power and emit them from the signal emit ting ports
B1 , …, BN. A Butl er matrix feeding circuit , for example, may be used as the
signal distribution circuit B. The Butler matrix is generally known to be used for
changing the direct ion of transmitting beams.
[0018]
20 As shown in Fig. 2, according to the signal distribution circuit B using a
But ler matrix feeding circuit , when the first signal S1 is input from the signal input
port C1, N number of seco nd s i gn als G1 , …, GN with equ al power are out put i n a
distri but ed mann er f r om th e s i gn al emitt in g po rts B1, …, BN. At t his t ime, th e
sign al dist ribut ion ci r cuit B add s a ph as e d iff erence wit h a li near sl op e θ 1 t o th e N
25 number of second signals G1, …, GN to be emitted from the signal emit ting ports
B1 , …, BN. A spi ral beam H is formed using such properties. To be specific,
the signal lines D1 , …, DN with equ al l en gth are conn ect ed fr om th e s i gn al
emitti n g p or ts B1 , …, BN to t he ant enn a elements A1 , …, AN ( see Fi g. 1 ).
[0019]
30 Further, the antenna elements A1, …, AN are equally spaced on the
circumference of circle. Thus, when the second si gn als G1, …, GN are emitt ed
fr om th e an tenn a elements A1, …, AN s equenti all y at sp ecifi ed int er v als i n a
certain twist direction (rightward twist or leftward twist), the spiral beam H is
formed from the signal emitting means A as shown in Fig. 3. The di rection of
8
twist of the spiral beam is changed according to the correspondence between the
ant enn a el ements A1, …, AN and t he si gnal lin es D1, …, DN. The mod e of th e
OAM to form the spiral beam H involves the case of N=2. In the case of N=2, the
twist direction may be any of rightward twist and leftward twist . In the case of
N=3 or more, the twist direction of the spiral beam H 5 can be determined.
[0020]
As shown in Fig. 4, the Butler matrix general ly has a plurality of signal
input po rts C1, …, CM (wh er e M is a po si tive int eger s atis f yin g M≤N) , and b y
ch an gi n g th e si gn al i nput po rts C1, …, CM fo r inp uttin g th e fi rst si gn als S1, …,
10 SM, it is possible to change the slope θN of a linearly sloped phase difference that
appears at the signal emitting ports B1, …, BN. Fo r ex ample, the fi rst si gn al S2
that is i nput to th e si gnal in put po rt C2 is output as th e seco nd si gn als G1 , …, GN
to which a p hase di ff er en ce with a lin ear s lope θ2 is ad ded. Usin g su ch
properties, the spiral pitch of the spiral beam H can be changed corresponding to
15 the signal input ports C1, …, CM. Thus, it is possible to form a signal to be
output from the signal emit ting means A as the spiral beam H having the spiral
pitch co rr esp ondi n g t o th e si gn al i nput po r ts C1, …, CM, th e eq uiph as e s u rface of
which is inclined spirally.
[0021]
20 Specifically, the signal distribution circuit B generates, from the input
fir st si gn al S, th e N n umber of s econd si gn als G1 , …, GN havin g a ph as e
difference from one another, and outputs the N number of second s i gn als G1, …,
GN t o t he N number of ant en na elemen ts A1, …, AN, resp ecti vel y, s o th at th e
spiral beam H, the equiphase surface of which is inclined spirally, is output from
25 the signal emi tting means A. At this time, the signal distribut ion circuit B
distri but es th e si gn al so th at th e s econd si gnals G1, …, GN h avi n g a s peci fied
phase difference, the phase difference increasing in incremental steps (by equal
differences) in the circumferential direct ion, are input to the antenna elements A1,
…, AN t hat ar e adjacent in the signal emit ting means A. Although an example of
30 using a Butler matrix feeding circuit for the signal distribution circuit B is shown
in the above description, any circui t may be used as long as it can output the
secon d si gn als G1, …, GN so that the spiral beam H is formed from each of the
ant enn a el ements A1, …, AN th at are equ all y sp aced o n t he ci r cumf er en ce o f
circle. Further, the phase differences added to the second signals are not
9
necessarily at equal intervals (at equal differences).
[0022]
A process of a wireless transmitting method that forms the spiral beam H
by the wireless transmitting antenna 10 is briefly described hereinafter with
reference 5 to Fig. 5.
[0023]
In the wireless transmitting antenna 10, the signal distribution cir cuit B
distri but es th e fir st si gnal S th at is i nput to an y o f t he si gnal in p ut po rts C1, …,
CM into th e N n umb er o f s econ d si gn als G1, …, GN with equ al power (S 100 ).
10 The signal distribution circuit B adds an incremental phase difference to each of
the N numb er o f seco nd si gn als G1, …, GN to b e o utput (S 101 ). Th e si gn al
distri buti on cir cuit B dis tri but es th e N n umber of s eco nd si gnals G1, …, GN t o th e
N n umb er o f ant en na el ements A1 , …, AN, r esp ectiv el y, s o t hat the spi r al b eam H,
the equiphase surface of which is inclined spirally, is formed from the signal
15 emitting means A (S102).
[0024]
As described above, according to the wireless transmitting antenna 10, the
si gn al t hat is outp ut f rom each o f t h e ant en na el ements A1, …, AN can be formed
as the spiral beam H whose equiphase surface is inclined spirally. Further,
20 according to the wireless transmi tting antenna 10, when forming the signal into the
spiral beam H, the spiral pitch of the spiral beam H can be changed arbi trarily.
[0025]
[Second exemplary embodiment]
In the first exemplary embodiment, the signal that is output from each of
25 the antenna elements A1, …, AN is formed as the spiral beam having the spiral
pitch co rr esp ondi n g t o th e si gn al i nput po r ts C1, …, CM, th e eq uiph as e s ur f ace of
which is inclined spirally, in the wireless transmitting antenna 10. In this
exemplary embodiment, a plurality of spiral beams having different spiral pitches
are formed using the wireless transmitting antenna 10 for multiplexing
30 communicat ions. In the following description, the same names and symbols are
used for the parts that are the same as those in the first exemplary embodiment ,
and the redundant description is omit ted as appropriate.
[0026]
As shown in Fig. 6, the wireless transmitting antenna 10 includes a signal
10
distri buti on ci rcuit B that h as a plu r alit y o f si gn al in put po rts C1, …, CM and a
plur alit y o f si gn al emittin g po rts B1, …, BN. Th e s tr uct ur e of the si gn al
distribution circuit B which has an 8 (=M) input , 8 (=N) output But ler matrix
feeding circui t i s s hown i n thi s ex ampl e. When th e fir st si gn als S1, …, SM ar e
input to an y o f t he si gnal in put po rts C1, …, CM, p has e di ff er ence 5 s with different
linear slopes are ad d ed t her eto , and N number o f seco nd s i gn als G1, …, GN wit h
equal power are output from t he si gn al emittin g po rts B1 , …, BN, r esp ectiv el y ( s ee
Fi g. 4) . Thu s, f rom the in put f irs t si gn al S, M n umb er of sp ir al b eams H1 , …, HM
with different spiral pitches are formed corresponding to the signal input ports C1,
10 …, CM.
[0027]
As shown in Fig. 7, wh en M numb er of di ff erent fir st si gn als S 1, …, SM
ar e r esp ectiv el y inp ut to th e M n umb er o f s ignal in put po rts C1, …, CM, p has e
dif fer en ces with dif f erent li near sl op es θ 1, …, θN are add ed r es pectiv el y to th e N
15 number of second signals G1, …, GN with equ al power corresponding to the signal
input por ts C1 , …, CM, and th e N numb er of s econ d si gnal s G1, …, GN with equ al
power ar e resp ectiv el y out put f rom th e si g nal emit tin g po rts B1 , …, BN. Th e
secon d si gn als G1, …, GN co r respo ndin g to t h e si gn al in put port s C1 , …, CM are
seq uenti all y outp ut fr om th e ant en na el ements A1, …, AN at s pecif ied times at
20 equal intervals, and M number of spiral beams H1, …, HM with different spiral
pitches are thereby formed simultaneously. Therefore, the wireless transmitting
antenna 10 can simul taneously multiplex and transmit the plural ity of spiral beams
H1, …, HM.
[0028]
25 A process of a wireless transmitting method that forms the plurality of
spiral beams H with different spiral pitches by the wireless transmitting antenna 10
is briefly described hereinafter with reference to Fig. 8.
[0029]
In the wireless transmitting antenna 10, the signal distribution circuit B
30 distributes and outputs each of the M number of different first signals S1, …, SM
that are input to each of the si gn al i nput p orts C1, …, CM i nto the N numb er o f
secon d si gn als G1, …, GN with equ al power co rr es pon din g to the si gnal in put
port s C1 , …, CM (S2 00) . Th e si gn al di st ribut ion ci r cuit B add s a di ff erent
incremental phase difference to each of the N number of distributed second signals
11
G1, …, GN and out p uts th em f rom th e si g nal emit tin g po rts B1 , …, BN (S2 01 ).
The si gn al di stri buti o n ci rcuit B dist rib ut es the s econ d si gnal s G1, …, GN to th e N
numb er o f ant enn a el ements A1 , …, AN, r esp ectiv el y, s o th at the signal emit ting
means A forms the M number of different spiral beams H, the equiphase surfaces
of which are inclined 5 spiral ly (S202).
[0030]
As described above, according to the wireless transmit ting antenna 10, it is
possible to simultaneously multiplex and transmit the plural ity of spiral beams H1,
…, HM.
10 [0031]
[Third exemplary embodiment]
An antenna that has the same structure as the wireless transmitting antenna
10 can be used also as a receiving antenna for the wireless transmitting antenna 10.
[0032]
15 As shown in Fig. 9, a wireless receiving antenna 20 includes a signal
receivi n g means K havin g X numb er o f ant enn a el ements K1, …, KX (wher e X is
an integer of 2 or more) that are equally spaced on the circumference of circle, a
signal synthesis circuit (s ignal synthesis means) T for synthesizing a first signal Q
fr om X numb er of s econ d si gn als P 1, …, PX wi th eq ual power that ar e receiv ed
20 from the antenna elements K1, …, KX, respectively, and a signal output means R
having Y number of signal output ports R1, …, RY (wh er e Y i s a p ositi ve int eger
satis f yi n g Y≤X) f or o utputti n g t he fi rst si gnal Q. By this structure, the wireless
receiving antenna 20 outputs the received spiral beam H as the first signal Q from
the si gn al out put po rt s R1, …, RY. T he n umber X o f the antenna elements K1,
25 …, KX may be greater than the number N of the antenna elements A1, …, AN in
the wireless transmitt ing antenna 10.
[0033]
The ant enn a el ements K1, …, KX ar e equally spaced on the circumference
of circle with a diameter of 30cm, for example. Those plurali ty of antenna
30 elements K1, …, KX constitute the signal receiving means K. A parabolic
ant enn a ma y b e us ed as each o f t he ant enn a el ements K1 , …, KX, fo r ex ampl e.
The signal receiving means K and the signal synthesis circuit T are connected
through a signal waveguide U. The signal waveguide U has X number of signal
lines U1, …, UX wit h equ al l en gth. T he si gn al lin es U1, …, UX co nn ect X
12
numb er o f si gn al in p ut po rts V1, …, VX o f th e si gn al s ynt hesis ci rcuit T and th e
antenna elements K1, …, KX. Coax ial cables o r waveguid es ma y be us ed as th e
si gn al li nes U1, …, UX.
[0034]
The signal synthesis circuit T synthesizes a signal from 5 the second signals
P1, …, PX wit h equ al power t hat ar e i nput f rom t he plu r alit y o f si gn al inpu t p ort s
V1, …, VX an d out p uts th e s ynt h esized si gnal as t he fir st si gnal Q f rom an y o f th e
si gn al o utpu t p ort s R1, …, RY in acco rd ance with th e sp ir al pi tch of th e s pir al
beam H. A Butler matrix feeding circui t may be used as the signal synthesis
10 circuit T, for example. The signal synthesis circuit T has the same structure as
the signal distribution circuit B in the wireless transmi tting antenna 10 (see Fig.
2). T hus , i f th e second si gn als P1, …, PX ar e i nput to th e si g nal dist rib ution
circuit B in an opposi te manner, the first signal Q is synthesized and output , which
is the operation of the signal synthesis circuit T. Therefore, the wireless
15 receiving antenna 20 can output the spiral beam H as the first signal Q by the
operation opposi te to the operation of the wireless transmitting antenna 10.
[0035]
Specifically, the spiral beam whose equiphase surface is incl ined spiral ly
which is received by the signal receiving means K having the X number of antenna
20 elements K1, …, KX equally spaced on the circumference of circle is input as the
X number o f s econd s ignals P1, …, PX t o t he si gn al s yn th esis ci rcuit T fr om th e N
number of ant enn a el ements K1 , …, KX, r esp ectiv el y, and th e s ignal s yn th esis
circuit T adds a phase difference to each of the X number of second signa ls P 1, …,
PX, synthesizes the first signal Q therefrom, and outputs the first signal Q. Then,
25 the signal synthesis circuit T adds a specified phase difference to the X number of
secon d si gn als P 1, …, PX th at ar e i nput f r om th e ant en na el ements adj acent in the
signal receiving means K so that the phase difference decreases in decremental
steps in the circumferential direction.
[0036]
30 Although an example of using a Butler matrix feeding circuit for the signal
synthesis circui t T is shown in the above descri ption, any circui t may be used as
lon g as it can r eceiv e the spi r al b eam H fr om each of th e ant en na el ements K1, …,
KX equally spaced on the circumference of circle and output the first signal Q.
Further, the phase differences to be added to the second si gn als P1, …, PX ar e n ot
13
necessarily at equal intervals.
[0037]
A process of receiving the spiral beam H by the wireless receiving antenna
20 is described hereinafter with reference to Fig. 10.
5 [0038]
When the spiral beam H is transmitted from the wireles s transmitting
antenna 10, the wireless receiving antenna 20 sequentially receives the second
si gn als P 1, …, PX in a cert ain twi st di r ecti on fr om th e X numb er o f ant en na
el ements K1, …, KX, resp ecti v el y, t hat are equ all y sp aced on t h e cir cumf er en ce o f
10 circle (S300). Because an incremental phase difference has been added to each of
the seco nd si gn als P1 , …, PX, th e si gn al s yn th esis ci r cuit T ad ds a d ecr ement al
phase difference, inversely to the incremental phase difference, to each of the
second signals P1, …, PX and s ynt hesizes therefrom (S301). The signal synthesis
cir cu it T out puts th e fir st si gn al Q fr om an y o f th e si gn al out put po rts R1, …, RY
15 (S302).
[0039]
As described above, according to the wireless receiving antenna 20, i t is
possible to output the received spiral beam H as the first signal Q.
[0040]
20 [Fourth exemplary embodiment]
The wireless receiving antenna 20 can receive Y number of mult iplexed
spiral beams H with different spiral pitches that are transmit ted by the wireless
transmitting antenna 10 in the second exemplary embodiment and output them as Y
number of first signals Q. In the following description, the same names and
25 symbols are used for the parts that are the same as those in the other exemplary
embodiments, and the redundant desc ription is omitted as appropriate.
[0041]
As shown in Fig. 11, the wireless receiving antenna 20 includes a signal
s ynth esi s cir cui t T h avin g a plu ralit y of si gnal in put po rts V1, …, VX an d a
30 plurality of signal output ports R1, …, RY. The structure of t he signal synthesis
circuit T that has a Butler matrix feeding circuit where X=8 and Y=8 is shown in
this example. The signal synthesis circui t T has the same structure as the signal
distribution circuit B in the second embodiment . Specifically, when the signal
synthesis circuit T receives Y number of spiral beams with different spiral pi tches,
14
it adds linear phase differences having slopes that are inverse of the slopes
co rr es pond in g to t he si gn al o utpu t p ort s R1, …, RY to th e X number o f r eceiv ed
second si gn als P 1, …, PX, respectively, synthesizes the Y number of first signals
Q therefrom, and outputs the Y number of first signals Q from the signal output
port s R1 , …, RY, respectively, by the opposite operation to the signal 5 distribution
circuit B.
[0042]
A process of receiving signals containing Y number of spiral beams H with
different spiral pitches by the wireless receiving antenna 20 is described
10 hereinafter wi th reference to Fig. 12.
[0043]
When the Y number of spiral beams H with different spiral pitches are
transmitted from the wireless transmitting antenna 10, the wireless receiving
ant enn a 20 r ecei ves t he seco nd si gn als P1, …, PX in a cert ain twist dir ectio n
15 respectively from the X number of antenna elements K1, …, KX that are equally
spaced on the circumference of circle (S400). Because an incremental phase
dif fer en ce h as been added to th e s econ d si gnal s P1 , …, PX, th e si gn al s yn th esi s
circuit T adds a decremental phase difference, inversely to the incremental phase
difference, to each of the s econd si gnal s P 1, …, PX and s ynt hes izes th e fi rst
20 signals Q therefrom (S401). The signal synthesis circuit T outputs the Y number
of fi rst s i gn als Q f rom th e si gn al o utput p orts R1, …, RY (S4 0 2).
[0044]
As described above, according to the wireless rece iving antenna 20, i t is
possible to receive the Y number of mult iplexed spiral beams H with different
25 spiral pitches that are transmitted by the wireless transmitt ing antenna 10 and
output them as the Y number of first signals Q.
[0045]
[Fifth exemplary embodiment]
By the wireless transmitting antenna 10 and the wireless receiving antenna
30 20 described above, i t is possible to wirelessly transmi t and receive signals using
the spiral beams H.
[0046]
As shown in Fig. 13, a wireless transmitting and receiv ing system 100
includes the wireless transmitting antenna 10 and the wireless receiving antenna
15
20. According to the wireless transmitting and receiving system 100, it is
possible to transmit and receive signals containing Y number of multiplexed spiral
beams H with different spiral pitches.
[0047]
[Sixth exemplary 5 embodiment]
As described in Non Patent Literature 2, the spiral beam H increases in
outside diameter like a torus as the transmitting and receiving distance becomes
longer. On the other hand, the diameter of the circumference where the antenna
el ements K1, …, KX ar e placed of th e wir el ess r eceiv in g anten na 20 ma y b e
10 changed based on the transmitting and receiving distance. For example, the
diameter of the circumference of the wireless receivin g antenna 20 may be
enlarged when the transmitting and receiving distance is long. Further, in order
to suppress an increase in the outside diameter of the spiral beam H, the diameter
of t he cir cumf er en ce wh er e t he antenn a el ements A1, …, AN ar e placed of the
15 wireless transmitting antenna 10 may be changed based on the transmi tting and
receiving distance. For example, the diameter of the circumference of the
wireless transmitting antenna 10 may be enlarged when the transmitting and
receiving distance is long.
[0048]
20 [Seventh exemplary embodiment]
As s hown i n Fi g. 1 4, the an tenn a elements A1, …, AN o f t he wi rel es s
transmitting antenna 10 may be a sub-array of an array antenna, instead of a
parabolic antenna, which forms a wireless transmit ting antenna 40. Likewise, the
ant enn a el ements K1, …, KX o f th e wi rel ess r eceivin g ant enn a 20 ma y be a
25 sub-array of an array antenna, instead of a parabolic antenna (not shown).
[0049]
[Eighth exemplary embodiment]
As shown in Fig. 15, a wireless transmitting antenna 30 includes M
numb er o f ot her si gn al i nput po rts Z1 , …, ZN f or inp uttin g M numb er o f di f fer ent
30 other first signals W orthogonal to the first signal S for forming a spiral beam J
which is an orthogonally polarized wave of the spiral beam H transmi tted by the
wireless transmitting antenna 10, and another signal distribution circuit E that
receiv es ot her f irst si gnal s W and o utp uts N numb er of oth er s econ d si gn al s F1, …,
FN o rtho gon al to t he secon d si gn als G1, …, GN. T he wi r el ess t ransmitti n g
16
antenna 30 can thereby transmit a spiral beam I wi th VH-polarized waves. With
use of a wireless receiving antenna (not shown) having the same structure as the
wireless transmitting antenna 30, it is possible to receive the spiral beam I with
VH-polarized waves and output M number of first signals and M number of
different other 5 first signals.
[0050]
It should be noted that the present invention is not limited to the
above-described exemplary embodiment and may be varied in many ways within
the scope of the present invention. For ex ampl e, f or th e an tenn a el ements A1, …,
10 AN and the antenna elements K1, …, KX, dipole antennas, helix antenna or horn
antennas may be used, for example, besides those described in the above
exemplary embodiments. Further, for the antenna elements K1 , …, KX at t he
receiving end, Yagi antennas may be used.
[0051]
15 Although the present invention is described as a hardware configuration in
the above exemplary embodiments, the present invention is not limited thereto.
The present invention may be impl emented by performing given processing by
DSP (Digi tal Signal Processing), and it can be implemented by executing a
program on DSP (Digital Signal Processor) or implemented with a logic circuit
20 configured on FPGA (Field Programmable Gate Array) or ASIC (Ap plication
Specific Integrated Circuit).
[0052]
The program can be stored and provided to the computer using any type of
non-transitory computer readable medium. The non -transitory computer readable
25 medium includes any type of tangible storage medium. Examples of the
non-transitory computer readable medium include magnetic storage media (such as
floppy disks, magnet ic tapes, hard disk drives, etc.), optical magnet ic storage
media (e.g. magneto-optical disks), CD-ROM (Read Only Memory), CD-R ,
CD-R/W, and semiconductor memories (such as mask ROM, PROM
30 (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random
Access Memory), etc.). The program may be provided to a computer using any type
of transitory computer readable medium. Examples of the transi tor y computer
readable medium include electric signals, optical signals, and electromagnetic
waves. The transitory computer readable medium can provide the program to a
17
computer via a wired communication line such as an electric wire or optical fiber
or a wireless communication line.
[0053]
While the invention has been particularly shown and described with
reference to exemplary embodiments thereof, the invention is not 5 limited to these
embodiments. It will be understood by those of ordinary skil l in the art that various
changes in form and details may be made therein without departing from the spirit
and scope of the present invention as defined by the claims.
Reference Signs List
10 [0054]
10 WIRELESS TRANSMITTING ANTENNA
20 WIRELESS RECEIVING ANTENNA
30 WIRELESS TRANSMITTING ANTENNA
40 WIRELESS TRANSMITTING ANTENNA
15 50 OAM ANTENNA
51 REFLECTING UNIT
100 WIRELESS TRANSMITTING AND RECEIVING SYSTEM
A SIGNAL EMITTING MEANS
A1,…,AN ANTENNA ELEMENT
20 B SIGNAL DISTRIBUTION CIRCUIT
B1 ,…,BN SIGNAL EMITTING PORT
C1,…,CM SIGNAL INPUT PORT
D SIGNAL WAVEGUIDE
D1,…,DN SIGNAL LINE
25 E SIGNAL DISTRIBUTION CIRCUIT
F1 ,…, FN OTHER SECOND SIGNAL
G1,…,GN SECOND SIGNAL
H SPIRAL BEAM
H1,…,HM SPIRAL BEAM
30 I SPIRAL BEAM
J SPIRAL BEAM
K SIGNAL RECEIVING MEANS
K1,…,KX ANTENNA ELEMENT
M INTEGER
18
N INTEGER
P1,…,PX SECOND SIGNAL
Q FIRST SIGNAL
R SIGNAL OUTPUT MEANS
R1,…,RY SIGNAL 5 OUTPUT PORT
S1,…,SM FIRST SIGNAL
T SIGNAL SYNTHESIS CIRCUIT
W FIRST SIGNAL
X INTEGER
10 Y INTEGER
Z1,…, ZN SIGNAL INPUT PORT

WE CLAIM:
1. A wireless signal t ransmitting antenna comprising:
signal emitting means having N number of antenna elements (where N is
an integer satis f yin g N≥2 ) equ all y sp aced on a cir cumf er 5 ence of circle; and
signal distribution means for generating, from an input first signal, N
number of second signals having a phase difference from one another, and
output ting the N number of second signals to the N number of antenna elements,
respectively, so that a spiral beam with an equiphase surface inclined spirally is
10 output from the signal emit ting means.
2. The wireless signal transmitting antenna according to Claim 1, wherein
the signal distribut ion means distributes signals so that second signals having a
specified phase difference, the phase difference increasing in incremental steps in
15 the circumferential direction, are input to the antenna elements adjacent in the
signal emitting means.
3. The wireless signal transmitting antenna according to Claim 2, wherein
wh en M numb er of di ff erent fir st si gn als (wh er e M is an int eger s atis f yi n g M≤N)
20 are input, the signal distribution means generates and outputs the second signals to
the N number of antenna elements, respect ively, so that M number of different
spiral beams are output from the signal emitting means.
4. The wireless signal transmitting antenna according to Claim 3, further
25 comprising:
another signal distribution means for receiving M numb er of different
other first signals orthogonal to the first signal , and outputting N number of other
second signals orthogonal to the second signals so that orthogonally polarized
waves of the spiral beam are formed by the signal emitting means.
30
5. The wireless signal transmitting antenna according to any one of Claims
1 to 4, wherein a diameter of the circumference where the antenna elements are
placed is changed based on a signal transmitting and receiving distance.
20
6. A wireless signal receiving antenna comprising:
signal receiving means having X number of antenna elements (where X is
an integer satisfying X≥2 ) equ all y sp aced on a cir cumf er ence o f cir cl e; an d
signal synthesis means for receiving, as X number of second signals, spiral
beams with equiphase surfaces inclined spirally received by the 5 signal receiving
means from the N number of antenna elements, respectively, adding a phase
difference to each of the X number of second signals, synthesizing a first signal
therefrom, and output ting the first signal .
10 7. The wireless signal receiving antenna according to Claim 6, wherein the
signal synthesis means adds a specified phase difference to the X number of
second signals input from the antenna elements adjacent in the signal receiving
means so that the phase difference decreases in decremental steps in the
circumferential direction.
15
8. The wireless signal receiving antenna according to Claim 7, wherein
when the signal receiving means receives Y number of different spiral beams
(wh er e Y i s an in teger s atis f yi n g Y≤X), t h e si gn al s yn th esis means r ecei ves s econd
signals from the N number of antenna elements, respectively, and generates Y
20 number of different first signals.
9. The wireless signal receiving antenna according to Claim 8, further
comprising:
another signal synthesis means for outputt ing an another first signal
25 orthogonal to the first signal when the signal receiving means receives
orthogonal ly polarized waves of the spiral beams.
10. The wireless signal receiving antenna according to any one of Claims 6
to 9, wherein a diameter of the circumference where the antenna elements are
30 placed is changed based on a signal transmitting and receiving distance.
11. A wireless signal transmitting system comprising:
signal emitting means for outputting a transmission signal by N number of
ant enn a el ements (wh er e N i s an i nteger satisf yi n g N≥ 2); and
21
signal distribution means for generating, from an input first signal, N
number of second signals having a phase difference from one another, and
output ting the N number of second signals to the N number of antenna elements,
respectively, wherein
the N number of antenna elements are equally spaced 5 on a circumference
of circle.
12. The wireless signal transmit ting system according to Claim 11,
wherein when M number of different first signals (where M is an integer satisfying
10 M≤N) are input , the signal distribution means generates and outputs the second
signals to the N number of antenna elements, respectively, so that M number of
different transmission signals are output from the signal emitting means.
13. The wireless signal transmit ting system according to Claim 11 or 12,
15 wherein the signal emitting means outputs an OAM transmission signal.
14. The wireless signal transmit ting system according to Claim 11 or 12,
wherein the signal emitting means outputs a transmission sign al with an equiphase
surface incl ined spirally.
20
15. A wireless signal transmitting method comprising:
generat ing, from an input first signal, N number of second signals having a
phase difference from one another; and
output ting the N number of second s ignals to N number of antenna
25 elements, respectively, so that a spiral beam with an equiphase surface incl ined
spirally is output from a signal emi tting means having the N number of antenna
el ements (wh er e N is an int eger s atis f yi n g N≥2 ) eq ual l y sp aced on a circumference
of circle.
30 16. The wireless signal transmit ting method according to Claim 15,
wherein signals are distributed so that second signals having a specified phase
difference, the phase difference increasing in incremental steps in the
circumferential direction, are input to the antenna elements adjacent in the signal
emitting means.
22
17. The wireless signal transmit ting method according to Claim 16,
wherein when M number of different first signals (where M is an integer
satis f yi n g M≤N) are i nput, the second signals are generated and output to the N
number of antenna elements, respectively, so that M number of 5 different spiral
beams are output from the signal emitting means.
18. The wireless signal transmit ting method according to Claim 17,
comprising:
10 receiving M number of different other first signals orthogonal to the first
signal and outputting N number of other second signals orthogonal to the second
signals so that orthogonal ly polarized waves of the spiral beam are formed by the
signal emitting means.
15 19. The wireless signal transmit ting method according to any one of
Claims 15 to 18, wherein a diameter of the circumference where the antenna
elements are placed is changed based on a signal transmitt ing and receiving
distance.
20 20. A wireless signal receiving method comprising:
receiving, as X number of second signals, spiral beams wi th equiphase
surfaces inclined spirally received by a signal receiving means having X number of
ant enn a el ements (wh er e X i s an i nteger satisf yi n g X≥ 2) e qually spaced on a
circumference of circle from the N number of antenna elements, respectively,
25 adding a phase difference to each of the X number of second signals, synthesizing
a first signal therefrom, and outputting the first signal.
21. The wireless signal receiving method according to Claim 20, wherein a
specified phase difference is added to the X number of second signals input from
30 the antenna elements adjacent in the signal receiving means so that the phase
difference decreases in decremental steps in the circumferential direction.
22. The wireless signal receiving method according to Claim 21, wherein
wh en Y n umb er o f di ff erent s pir al beams (wh er e Y is an in teger sati sf yi n g Y≤X)
23
are received by the signal receiving means, second signals are inpu t from the N
number of antenna elements, respectively, and Y number of different first signals
are generated.
23. The wireless signal receiving method according 5 to Claim 22,
comprising:
output ting another first signal orthogonal to the first signal when
orthogonal ly polarized waves of the spiral beams are received by the signal
receiving means.
10
24. The wireless signal receiving method according to any one of Claims
20 to 23, wherein a diameter of the circumference where the antenna elements are
placed is changed based on a signal transmitting and receiving distance.