1. An a n t e n n a c o m p r i s i n g : a f e e d e r c i r c u i t l a y e r in which a w a v e g u i d e e n t r a n c e and a f i r s t 5 w a v e g u i d e t h r o u g h w h i c h a radio wave is propagated are formed; an antenna layer in which a p l u r a l i t y of a n t e n n a e l e m e n t s a r e formed; and a c o u p l i n g layer t h a t i s f o r m e d b e t w e e n the feeder c i r c u i t l a y e r and t h e a n t e n n a l a y e r a n d c o u p l e s t h e f i r s t w a v e g u i d e t o t h e p l u r a l i t y 10 o f a n t e n n a e l e m e n t s w i t h a w a v e g u i d e , w h e r e i n t h e p l u r a l i t y o f a n t e n n a e l e m e n t s i n c l u d e a f i r s t antenna element, a s e c o n d a n t e n n a e l e m e n t , and a t h i r d a n t e n n a e l e m e n t , t h e s e c o n d and t h i r d a n t e n n a e l e m e n t s b e i n g a d j a c e n t t o t h e f i r s t a n t e n n a e l e m e n t , the f i r s t a n d s e c o n d a n t e n n a e l e m e n t s a r e a r r a n g e d i n such a 15 manner t h a t c e n t e r s of the f i r s t a n d s e c o n d a n t e n n a e l e m e n t s a r e aligned in a f i r s t d i r e c t i o n p a r a l l e l t o a p r i n c i p a l s u r f a c e of the a n t e n n a l a y e r , and t h e t h i r d a n t e n n a element is a r r a n g e d i n such a manner that the ! t h i r d antenna e l e m e n t i s s e p a r a t e d f r o m the f i r s t a n t e n n a e l e m e n t in a 20 s e c o n d d i r e c t i o n and c e n t e r s o f t h e f i r s t a n d t h i r d a n t e n n a e l e m e n t s are not aligned in the s e c o n d d i r e c t i o n , t h e s e c o n d d i r e c t i o n b e i n g p a r a l l e l to the p r i n c i p a l s u r f a c e of the a n t e n n a l a y e r a n d perpelldicular to the f i r s t d i r e c t i o n .

2. T h e a n t e n n a a c c o r d i n g t o Claim 1 , w h e r e i n in t h e c o u p l i n g l a y e r , a s e c o n d w a v e g u i d e that collnects t h e f i r s t antenna element and the f i r s t w a v e g u i d e to each other and a third waveguide that connects the third a n t e n n a e l e m e n t and t h e f i r s t w a v e g u i d e t o each otller are formed, a d i s t a n c e b e t w e e n a f i r s t connection end that connects the f i r s t waveguide and t h e s e c o n d w a v e g u i d e t o e a c h o t h e r and t h e waveguide e n t r a n c e formed in t h e f e e d e r c i r c u i t l a y e r i s e q u a l to a d i s t a n c e between a second connection end t h a t c o n n e c t s the f i r s t waveguide and t h e t h i r d w a v e g u i d e t o e a c h other and the w a v e g u i d e e n t r a n c e formed 15 in t h e f e e d e r c i r c u i t l a y e r , a c e n t e r of t h e f i r s t c o n n e c t i o n e n d a n d a c e n t e r of a third I conneciio-11 end t h a t c o n n e c t s the f i r s t ailtelllla elelllent and the secolld waveguide to each o t h e r a r e s e p a r a t e d f r o m e a c h o t h e r in the f i r s t 5 d i r e c t i o n by a f i r s t v a l u e , and a c e n t e r of the s e c o n d c o n n e c t i o n e n d a n d a c e n t e r of a f o u r t h I c o n n e c t i o n e n d t h a t c o n n e c t s t h e t h i r d a n t e n n a e l e m e n t a n d the third waveguide to each o t h e r a r e s e p a r a t e d f r o m e a c h o t h e r in a d i r e c t i o n o p p o s i t e to the f i r s t d i r e c t i o n by the f i r s t v a l u e . I 10 1 3. The a n t e n n a a c c o r d i n g t o C l a i m 1 o r 2 , wherein the p l u r a l i t y , of a n t e n n a e l e m e n t s a r e formed in a s i z e e q u a l to o r g r e a t e r than a w a v e l e n g t h o f a r a d i a t e d w a v e . 15 4. The a n t e n n a a c c o r d i n g to a n y o n e of Claims 1 to 3, wherein the plui-ality of antenna e l e m e n t s e a c h h a v e a p y r a m i d a l shape with a v e r t e x f a c i n g the c o u p l i n g l a y e r .

5. The antenna a c c o r d i n g t o C l a i m 4, w h e r e i n t h e p l u r a l i t y of 20 a n t e n n a e l e m e n t s e a c h h a v e a q u a d r a n g u l a r p y r a m i d s h a p e w i t h a v e r t e x f a c i n g the c o u p l i n g l a y e r .

6. The antenna a c c o r d i n g to Clainl 5, wherein o p e n i n g s o f t h e p l u r a l i t y of a n t e n n a e l e m e n t s that are l o c a t e d at 25 a s i d e o p p o s i t e to the c o u p l i n g layer h a v e a s q u a r e s h a p e , a n d a l e n g t h o f a s i d e of the s q u a r e s h a p e is equal to o r m o r e than a wavelength of a radiated wave.

7. The a n t e n l ~ a a c c o r d i n g t o a n y one of Claims 1 to 6, wherein 30 t h e p l u r a l i t y o f a n t e n n a e l e m e n t s are arranged in a staggered manner.

8. The a l l t c l ~ n a a c c o r d i n g t o a n y one o f C l a i m s 1 to 7, wherein t h e s e c o n d and third w a v e g u i d e s a r e formed in a m u l t i - s t a g e crank

DESCRIPTION
ANTENNA
T e c h n i c a l F i e l d
5 [0001]
T h e p r e s e n t i n v e n t i o n r e l a t e s t o an a n t e n n a .
Background Art
[0002]
10 S i d e - l o b e c h a r a c t e r i s t i c s w h i c h are r e q u i r e d for antennas used in
r a d i o s y s t e m s , such as p o i n t - t o - p o i n t , are s p e c i f i e d in i n t e r n a t i o n a l
s t a n d a r d s , a n d i t i s n e c e s s a r y to s u p p r e s s the s i d e l o b e level to be
lower than a p r e d e t e r m i n e d l e v e l . T y p i c a l i n t e r n a t i o n a l s t a n d a r d s are
E T S I ( E u r o p e a n T e l e c o m m u n i c a t i o n s S t a n d a r d s I n s t i t u t e ) s t a n d a r d s .
15 [0003]
A p a r a b o l a a n t e n n a i s generally u s e d a s a n a n t e n n a f o r p o i n t - t o -
p o i n t c o m m u n i c a t i o n . H o w e v e r , when t h e p a r a b o l a a n t e n n a s a t i s f i e s
t h e s i d e - l o b e s t a n d a r d s , t h e t h i c k n e s s of t h e a n t e n n a i n c r e a s e s , which
r e s u l t s in a n i n c r e a s e in t h e s i z e of the e n t i r e a p p a r a t u s . F o r t h i s
20 r e a s o n , a p l a n a r a n t e n n a i s d e s i r e d .
[0004]
In a m i l l i m e t e r wave band, a p l a n a r antenna i n c l u d i n g a
waveguide with a t r a n s m i s s i o n l o s s lower than that o f a m i c r o s t r i p line
is used. As a c o n f i g u r a t i o n o f s u c h a p l a n a r a n t e n n a , a c o n f i g u r a t i o n
25 in which horn a n t e n n a s a r e arranged i n a n a r r a y i s known ( P a t e n t
L i t e r a t u r e 1 ) . P a t e n t L i t e r a t u r e 1 p r o p o s e s a p l a n a r a n t e n n a i n which
horn antennas are arranged in a s q u a r e l a t t i c e . T h i s a n t e n n a is
c h a r a c t e r i z e d by i n c l u d i n g a box horn at which each horn antenna has a
s t e p - l i k e c h a n g e in s h a p e .
3 0
C i t a t i o n L i s t
P a t e n t L i t e r a t u r e
[0005]
3
[ P a t e n t L i t e r a t u r e 11 J a p a n e s e Patent No. 3 7 1 8 5 2 7
Summary of Invention
T e c h n i c a l Problem
5 [0006]
I n g e n e r a l , when the d i s t a n c e b e t w e e n a n t e n n a e l e m e n t s is
l o n g e r t h a n one w a v e l e n g t h o f a r a d i a t e d wave, a grating lobe is
g e n e r a t e d . This r e s u l t s in s i g n i f i c a n t d e t e r i o r a t i o n o f the side lobe
l e v e l . In o r d e r t o s u p p r e s s s i d e l o b e s g e n e r a t e d i n r a d i o wave
10 r a d i a t i o n c h a r a c t e r i s t i c s , i t i s n e c e s s a r y t o a r r a n g e horn antennas with
as h i g h a d e n s i t y as p o s s i b l e . A c c o r d i n g l y , t h e s t r u c t u r e of the horn
antennas and the s t r u c t u r e of waveguides f o r g u i d i n g r a d i o w a v e s to
t h e h o r n a n t e n n a s are m i n i a t u r i z e d . A s a r e s u l t , i t i s d i f f i c u l t t o
p r e p a r e t h e p l a n a r a n t e n n a h a v i n g a m i n i a t u r i z e d s t r u c t u r e . Even if the
15 p l a n a r a n t e n n a can b e p r e p a r e d , a cost i n c r e a s e is u n a v o i d a b l e .
[0007]
T h e p r e s e n t i n v e n t i o n has been made i n v i e w of the abovem
e n t i o n e d c i r c u m s t a n c e s , a n d a n o b j e c t of the present i n v e n t i o n is to
p r o v i d e a n a n t e n n a having e x c e l l e n t s i d e - l o b e s u p p r e s s i o n
20 c h a r a c t e r i s t i c s .
Solution to Problem
[OOOS]
An antenna a c c o r d i n g to an e x e m p l a r y a s p e c t o f t h e present
25 i n v e n t i o n i n c l u d e s : a f e e d e r c i r c u i t l a y e r in w h i c h a w a v e g u i d e
e n t r a n c e and a f i r s t w a v e g u i d e t h r o u g h which r a d i o w a v e s p r o p a g a t e
are formed; an a n t e n n a l a y e r in which a p l u r a l i t y o f a n t e n n a e l e m e n t s
are formed; and a c o u p l i n g l a y e r t h a t is fornled between t h e feeder
c i r c u i t layer and the a n t e n n a layer and c o u p l e s t h e f i r s t waveguide to
30 the p l u r a l i t y of a n t e n n a elelllents with a w a v e g u i d e . The p l u r a l i t y of
a n t e n n a e l e m e n t s i n c l u d e a f i r s t alltenna e l e m e n t . a s e c o n d a n t e n n a
e l e m c n t , and a third a n t e n n a e l e m e n t . t h e s e c o n d and third antenna
e l e n ~ c l ~bt se ing a d j a c e n t t o t h e f i r s t antenna e l e m e n t . The f i r s t and
second antenlla e l e m e n t s a r e arranged in s u c h a nlanner that centers of
4
t h e f i r s t and second a n t e n n a e l e m e n t s are aligned in a f i r s t d i r e c t i o n
p a r a l l e l t o a p r i n c i p a l s u r f a c e of the a n t e n n a l a y e r . T h e t h i r d a n t e n n a
element is arranged in such a m a n n e r t h a t the t h i r d a n t e n n a e l e m e n t is
s e p a r a t e d f r o m t h e f i r s t a n t e n n a e l e m e n t in a s e c o n d d i r e c t i o n and
5 c e n t e r s of the f i r s t and t h i r d a n t e n n a e l e m e n t s are not aligned i n t h e
s e c o n d d i r e c t i o n , the s e c o n d d i r e c t i o n b e i n g p a r a l l e l to the p r i n c i p a l
s u r f a c e of t h e a n t e n n a l a y e r and p e r p e n d i c u l a r t o the f i r s t d i r e c t i o n .
Advantageous E f f e c t s of Invention
10 [0009]
According to the p r e s e n t i n v e n t i o n , it is p o s s i b l e to provide an
a n t e n n a h a v i n g e x c e l l e n t s i d e - l o b e s u p p r e s s i o n c h a r a c t e r i s t i c s .
B r i e f D e s c r i p t i o n o f D r a w i n g s
15 [OOlO]
Fig. 1 is a p e r s p e c t i v e v i e w s c h e m a t i c a l l y s h o w i n g a
c o n f i g u r a t i o n of an a n t e n n a 1 0 0 ;
Fig. 2A is a t o p v i e w s c h e m a t i c a l l y showing t h e c o n f i g u r a t i o n o f
t h e a n t e n n a 100;
2 0 Fig. 2B is a t o p v i e w s c h e m a t i c a l l y showing a n a r r a n g e m e n t o f
horn a n t e n n a s 5 1 to 53;
F i g . 3A is a n e n l a r g e d s e c t i o n a l v i e w s c h e m a t i c a l l y s h o w i n g a
c o n f i g u r a t i o n o f a c r o s s - s e c t i o n o f t h e a n t e n n a 1 0 0 t a k e n a l o n g a line
I I I A - I I I A of Fig. 2A;
2 5 Fig. 3B is an e n l a r g e d s e c t i o n a l view s c h e m a t i c a l l y s h o w i n g a
c o n f i g u r a t i o n of a c r o s s - s e c t i o n of the antenna 100 t a k e n a l o n g a line
I I I B - I I I B o f F i g . 2A;
Fig. 4 is a diagram s c h e n ~ a t i c a l l ys h o w i i ~ ga c o n f i g u r a t i o n o f a
waveguide layer 3 and a coupling layer 2 when they are viewed from a
30 bottom l a y e r 4 ; and
Fig. 5 is a graph showing r a d i o wave r a d i a t i o n c h a r a c t e r i s t i c s o f
the a n t e n n a 1 0 0 .
Description o f Embodiments
5
[OOll]
Exemplary embodiments o f t h e p r e s e n t i n v e n t i o n will be
d e s c r i b e d b e l o w w i t h r e f e r e n c e t o the drawings. In the d r a w i n g s , t h e
same elements are denoted b y t h e s a m e r e f e r e n c e n u m e r a l s , a n d t h u s a
5 r e p e a t e d d e s c r i p t i o n i s omitted as needed.
[OO 121
F i r s t Exemplary Embodiment
F i r s t , a n a n t e n n a 100 a c c o r d i n g t o an e x e m p l a r y e m b o d i m e n t
will be d e s c r i b e d . F i g . 1 is a p e r s p e c t i v e view schematically showing
10 t h e c o n f i g u r a t i o n o f t h e a n t e n n a 100. The antenna 100 i n c l u d e s an
a n t e n n a l a y e r 1, a c o u p l i n g l a y e r 2, a w a v e g u i d e layer 3, and a bottom
layer 4. The a n t e n n a l a y e r 1, the c o u p l i n g l a y e r 2 , t h e w a v e g u i d e layer
3, a n d t h e b o t t o m l a y e r 4 are each formed o f , f o r e x a m p l e , a m e t a l .
The w a v e g u i d e l a y e r 3 and the b o t t o m l a y e r 4 c o n s t i t u t e a f e e d e r
15 c i r c u i t l a y e r 10.
[00 131
Fig. 2A is a t o p v i e w s c h e m a t i c a l l y showing the c o n f i g u r a t i o n o f
the a n t e n n a 100. In t h e a n t e n n a layer 1, horn antennas 5 each having a
q u a d r a n g u l a r p y r a m i d s h a p e a r e arranged in a s t a g g e r e d m a n n e r .
20 H e r e i n a f t e r , t h e horn a n t e n n a s a r e a l s o r e f e r r e d to simply as antenna
e l e m e n t s . The horn a n t e n n a s i n a d j a c e n t rows are e a c h a r r a n g e d wit11
an o f f s e t . In t h i s e x e m p l a r y e m b o d i m e n t , t h e horn a n t e n n a s 5 arranged
in a r o w B s l ~ o w n in Fig. 2A are o f f s e t in a d i r e c t i o n C ( a l s o r e f e r r e d
to a s a f i r s t d i r e c t i o n ) r e l a t i v e to t h e h o r n a n t e n n a s 5 arranged in a
25 row A shown in Fig. 2A. F u r t h e r , s i n c e t h e h o r n a n t e n n a s 5 a r e
arranged in a s t a g g e r e d m a n n e r , t h e c e n t e r of each horn antenna 5 in
the r o w A is at the s a m e d i s t a n c e from the c e n t e r between the two horn
a n t e n n a s 5 in t h e r o w B t h a t i s a d j a c e n t in a d i r e c t i o n D to t h e row A.
[00 141
3 0 Note that the d i r e c t i o n C is a d i r e c t i o n p a r a l l c l to t h e p r i n c i p a l
s u r f a c e of the a n t e n n a layer 1 and the d i r e c t i o n D ( a l s o r e f e r r e d to a s a
s e c o n d d i r e c t i o n ) is a d i r e c t i o n that i s p a r a l l e l to the p r i n c i p a l s u r f a c e
o f t h e antenna1 layer 1 and p e r p e n d i c u l a r t o the d i r e c t i o n C.
l00151
6
T h r e e a d j a c e n t horn antennas 51 to 5 3 a r e n o w c o n s i d e r e d . Fig.
2B is a t o p v i e w s c h e m a t i c a l l y s h o w i n g t h e a r r a n g e m e n t o f t h e h o r n
antennas 51 to 53. Upon c o n s i d e r i n g t h e a b o v e - m e n t i o n e d o f f s e t i n a
s i m p l i f i e d w a y , t h e s i g n i f i c a n c e of t h e o f f s e t c a n b e u n d e r s t o o d as
5 f o l l o w s . Here, a c a s e w h e r e t h e c e n t e r s of t h e h o r n a n t e n n a s 51 and 52
are aligned in t h e d i r e c t i o n C will b e d e s c r i b e d . I11 t h i s case, the horn
antenna 53 is s e p a r a t e d f r o m t h e horn antenna 51 in the d i r e c t i o n D. It
can be u n d e r s t o o d t h a t t h e h o r n antennas 51 and 5 3 a r e a r r a n g e d i n
such a m a n n e r t h a t t h e c e n t e r s of the horn antennas 51 and 53 are not
10 aligned in the d i r e c t i o n D.
[OO 161
N e x t , a c o n f i g u r a t i o n of a c r o s s - s e c t i o n of the antenna 100 will
be d e s c r i b e d . Fig. 3A is an e n l a r g e d s e c t i o n a l view schematically
showing a c o n f i g u r a t i o n of a c r o s s - s e c t i o n o f the a n t e n n a 1 0 0 t a k e n
15 a l o n g a l i n e I I I A - I I I A of F i g . 2 A . Fig. 3B is an enlarged s e c t i o n a l
view s c h e m a t i c a l l y showing a c o n f i g u r a t i o n of a c r o s s - s e c t i o n o f the
a n t e n n a 1 0 0 t a k e n along a l i n e I I I B - I I I B of Fig. 2A. T h e a n t e n n a layer
1 is stacked on the c o u p l i n g l a y e r 2. The c o u p l i n g l a y e r 2 i s s t a c k e d
o n t h e w a v e g u i d e l a y e r 3. The w a v e g u i d e l a y e r 3 is stacked on the
20 bottom layer 4. The a n t e n n a layer 1 , t h e c o u p l i n g l a y e r 2, the
w a v e g u i d e l a y e r 3, and the bottom layer 4 c a n b e s t a c k e d by various
j o i n i n g m e t h o d s , such as s c r e w i n g and a d h e s i o n u s i n g a11 a d h e s i v e .
[00 171
The c o u p l i n g l a y e r 2 is f o r m e d o f a coupling-1ayer.upper layer
25 21 and a c o u p l i n g - l a y e r lower layer 22. In the c o u p l i l ~ g - l a y e r upper
l a y e r 2 1 , upper waveguides w h i c h p e n e t r a t e the c o u p l i n g - l a y e r u p p e r
layer 21 a r e f o r m e d . At the l i n e I I I A - I I I A , an u p p e r waveguide 23A
which e x t e n d s in the d i r e c t i o n C a s s h o w n in Fig. 3A is formed i n the
c o u p l i n g - l a y e r upper layer 21. A right end o f t h e u p p e r waveguide
30 23A is coupled to a lower end of the c o r r e s p o n d i n g h o r n a n t e n n a 5 at a
connection end 27A ( a l s o r e f e r r e d to a s a third c o n n e c t i o n e n d ) . At
the line I I I B - I I I B , an u p p e r w a v e g u i d e 23B w h i c l ~ extends in the
d i r c c t i o n C as shown in Fig. 3B is formed in the c o u p l i n g - l a y e r u p p e r
layer 21. A left end of t h e u p p e r w a v e g u i d e 2 3 B i s coupled to a lower
7
end of t h e c o r r e s p o n d i n g horn a n t e n n a 5 at a c o n n e c t i o n end 27B (also
r e f e r r e d to as a f o u r t h c o n n e c t i o n e n d ) . T h a t i s , it can b e u n d e r s t o o d
t h a t t h e u p p e r w a v e g u i d e 2 3 A a t t h e l i n e IIIA-IIIA is coupled to the
c o r r e s p o n d i n g h o r n a n t e n n a 5 in a d i r e c t i o n o p p o s i t e t o the upper
5 waveguide 23B at t h e l i n e I I I B - I I I B .
[00 181
I n t h e c o u p l i n g - l a y e r lower layer 22, l o w e r w a v e g u i d e s which
p e n e t r a t e t h e c o u p l i n g - l a y e r lower l a y e r 2 2 are formed. A t t h e l i n e
I I I A - I I I A , a l o w e r w a v e g u i d e 2 4 A w h i c h e x t e n d s in the d i r e c t i o n C as
10 shown i n F i g . 3A is formed in the c o u p l i n g - l a y e r l o w e r l a y e r 2 2 . A
r i g h t end of the l o w e r w a v e g u i d e 2 4 A is c o u p l e d t o a l e f t end o f t h e
c o r r e s p o n d i n g u p p e r waveguide 23A. A t t h e l i n e I I I B - I I I B , a l o w e r
w a v e g u i d e 2 4 B which e x t e n d s in t h e d i r e c t i o n C as shown in Fig. 3 B i s
formed in the c o u p l i n g - l a y e r lower l a y e r 2 2 . A l e f t end of the lower
15 waveguide 24B is coupled to a r i g h t end of t h e u p p e r w a v e g u i d e 2 3 B .
[0019]
Each of t h e u p p e r waveguide 23A and t h e l o w e r w a v e g u i d e 24A
is a l s o r e f e r r e d to as a s e c o n d w a v e g u i d e . Each o f t h e upper
waveguide 23B a n d t h e lower w a v e g u i d e 24B i s a l s o r e f e r r e d to a s a
20 t h i r d w a v e g u i d e .
[0020]
In t h e w a v e g u i d e layer 3, a w a v e g u i d e 31 ( a l s o r e f e r r e d to as a
f i r s t w a v e g u i d e ) w h i c h p e n e t r a t e s the waveguide layer 3 i s f o r m e d .
The waveguide 31 is c o u p l e d t o a l o w e r end of the lower waveguide
25 24A and a l o w e r end of'the lower waveguide 24B.
[ 0 0 2 l ]
Note that a c e n t e r 26A of a connection end 25A ( a l s o r e f e r r e d to
as a f i r s t c o n n e c t i o n e n d ) , w h i c h c o n n e c t s the lower waveguide 24A
and t h e w a v e g u i d e 31 to e a c h o t h e r , and a c e n t e r 26B o f a connection
30 end 25B ( a l s o r e f e r r e d to as a s e c o n d c o n n e c t i o n e n d ) , which connects
the lower w a v e g u i d e 24B and t h e w a v e g u i d e 31 to each o t h e r , a r e
formed at p o s i t i o n s w h e r e n o o f f s e t is p r o v i d e d , u n l i k e t h e horn
a n t e n n a s 5. S p e c i f i c a l l y , i t can b e u n d e r s t o o d t h a t on t h e b a s i s of the
c e n t e r 26A of the c o n l ~ e e t i o ne nd 25A, at the l i n e I I I A - I I I A , radio
8
waves propagate in t h e u p p e r r i g h t d i r e c t i o n from t h e w a v e g u i d e 3 1 to
t h e l o w e r end of the horn a n t e n n a 5 t h r o u g h t h e l o w e r w a v e g u i d e 24A
and t h e u p p e r waveguide 23A. It can also be understood that on the
basis o f t h e c e n t e r 26B of the c o n n e c t i o n e n d 25B, a t t h e l i n e I I I B - I I I B ,
5 radio waves propagate in t h e u p p e r l e f t d i r e c t i o n f r o m t h e waveguide
31 to the lower end o f t h e h o r n a n t e n n a 5 t h r o u g h t h e l o w e r w a v e g u i d e
24B a n d the u p p e r w a v e g u i d e 23B.
[0022]
W i t h t h i s c o n f i g u r a t i o n , even i f t h e w a v e g u i d e 3 1 i s formed
10 w i t h o u t c o n s i d e r a t i o n o f the o f f s e t , the d i s t a n c e s f r o m t h e waveguide
31 to the h o r n a n t e n n a s 5 , w h i c h a r e o f f s e t at t h e l i n e I I I A - I I I A a n d
t h e l i n e I I I B - I I I B , can be made e q u a l , merely by o f f s e t t i n g t h e
w a v e g u i d e d i r e c t i o n s o f t h e u p p e r w a v e g u i d e and the lower waveguide
in o p p o s i t e d i r e c t i o n s by the same value AD ( a l s o r e f e r r e d to a s a f i r s t
15 v a l u e ) , t h e r e b y m a k i n g it p o s s i b l e to guide radio waves without
causing a n y p h a s e d i f f e r e n c e .
[0023]
Next, t h e c o n f i g u r a t i o n of the waveguide layer 3 will be
d e s c r i b e d . Fig. 4 is a d i a g r a m s c h e m a t i c a l l y s h o w i n g t h e c o n f i g u r a t i o n
20 of each of the w a v e g u i d e l a y e r 3 and t h e c o u p l i n g l a y e r 2 when t h e y
are v i e w e d f r o m t h e bottom layer 4. In t h e b o t t o m layer 4, a
w a v e g u i d e e n t r a n c e which p e n e t r a t e s t h e b o t t o m layer 4 is formed (not
shown). The waveguide e n t r a n c e i s c o u p l e d to the waveguide 31 at a
l o c a t i o n 3 2 shown in Fig. 4. A c c o r d i n g l y , radio waves are introduced
25 i n t o t h e w a v e g u i d e 31 through the w a v e g u i d e e n t r a n c e .
[0024]
In the w a v e g u i d e l a y e r 3 , the waveguide 31 i s formed a s a
w a v e g u i d e h a v i n g b r a n c h e s in such a m a n n e r t h a t t h e d i s t a n c e s from a
portion c o u p l e d t o the w a v e g u i d e e n t r a n c e ( i . e . , the location 32 shown
30 in Fig. 4) t o t h e c o u p l i n g e n d 25A and the coupling end 25R a r e e q u a l
to each, o t h e r . In o t h e r w o r d s , r a d i o w a v e s p r o p a g a t e from t h e o u t s i d e
to the connection e n d 25A a n d t h e c o n l ~ e c t i o n end 25R through the
waveguide e n t r a n c e at the same phase
[0025]
9
Next, the radio wave r a d i a t i o n c h a r a c t e r i s t i c s of the antenna 100
will b e d e s c r i b e d . Fig. 5 is a g r a p h s h o w i n g the radio wave r a d i a t i o n
c h a r a c t e r i s t i c s of t h e a n t e n n a 1 0 0 . R e f e r r i n g t o Fig. 5 , the radio wave
r a d i a t i o n c h a r a c t e r i s t i c s o f t h e a n t e n n a 100 are i n d i c a t e d by a solid
5 line L1. As c o m p a r a t i v e e x a m p l e s , t h e radio wave r a d i a t i o n
c h a r a c t e r i s t i c s o f a n antenna in which horn antennas are a r r a n g e d i n a
s q u a r e l a t t i c e , w i t h o u t p r o v i d i n g a n o f f s e t , a s d i s c l o s e d in Patent
L i t e r a t u r e 1 are i n d i c a t e d by a d a s h e d l i n e L 2 , a n d CLASS 2 s t a n d a r d s
o f t h e E T S I ( E u r o p e a n T e l e c o m m u n i c a t i o n s S t a n d a r d s I n s t i t u t e ) are
10 indicated by a t h i c k l i n e L3. The h o r i z o n t a l a x i s r e p r e s e n t s the
azimuth of a s u r f a c e taken a l o n g a l i n e V-V shown in Fig. 2 as an
o b s e r v a t i o n s u r f a c e . Note t h a t the f r o n t face o f t h e a n t e n n a 100 is
r e p r e s e n t e d by 0. The v e r t i c a l a x i s r e p r e s e n t s a g a i n .
[0026]
15 A s s h o w n in Fig. 5, it is u n d e r s t o o d t h a t , in the comparative
example (L2), s i d e lobes of a l a r g e g a i n o c c u r , w h i c h l o b e s exceed the
CLASS 2 s t a n d a r d s of the ETSI ( E u r o p e a n Telecommunications
S t a n d a r d s I n s t i t u t e ) (L3). T h a t i s , as m e n t i o n e d a b o v e , the s i d e l o b e s
in t h e c o m p a r a t i v e e x a m p l e ( L 2 ) are not s u f f i c i e n t l y s u p p r e s s e d .
20 100271
On the o t h e r hand, in the r a d i o w a v e r a d i a t i o n c h a r a c t e r i s t i c s
(L1) o f t h e a n t e n n a 1 0 0 , the side l o b e s a r e s u f f i c i e n t l y s u p p r e s s e d , and
thus the radio wave r a d i a t i o n c h a r a c t e r i s t i c s t h a t s a t i s f y t h e CLASS 2
s t a n d a r d s ( L 3 ) o f the E T S I ( E u r o p e a n ? ' e l e c o m ~ ~ ~ u n i c a t i oSntsa ndards
25 I n s t i t u t e ) c a n be a c h i e v e d . That i s , it can be understood that the horn
a n t e n n a s 5 a r e a r r a n g e d with an o f f s e t as in the c o ~ l f i g u r a t i o n of the
present i n v e n t i o n , t h e r e b y achieving an a n t e n n a h a v i n g r a d i o wave
r a d i a t i o n c h a r a c t e r i s t i c s in which t h e s i d e lobes are s u f f i c i e n t l y
s u p p r e s s e d .
30 [0028]
In the a b o v e - d e s c r i b e d c o m p a r a t i v e example (1,2). in order to
suppress the s i d e l o b e s , i t is n e c e s s a r y t o r e d u c e t h e o p e n i n g size of
e a c h h o r n a n t e n n a t o be smaller than the w a v e l e n g t h o f a radiated wave
(for e x a m p l e , m i l l i m e t e r w a v e ) , - a n d to i n c r e a s e the density of the llorn
10
a n t e n n a s t o b e a r r a n g e d . In t h i s c a s e , h o w e v e r , t h e s t r u c t u r e s o f t h e
h o r n a n t e n n a s and the w a v e g u i d e s l e a d i n g t o the h o r n a n t e n n a s are
m i n i a t u r i z e d , w h i c h makes it d i f f i c u l t t o p r e p a r e the antennas and
w a v e g u i d e s , r e s u l t i n g in an i n c r e a s e in the c o s t o f the a n t e n n a .
5 [0029]
On t h e o t h e r h a n d , in t h e c o n f i g u r a t i o n of the p r e s e n t i n v e n t i o n ,
t h e s i d e l o b e s c a n b e suppressed by the arrangement of the horn
a n t e n n a s , w h i c h e l i m i n a t e s t h e need to i n c r e a s e the d e n s i t y o f the horn
antennas to be a r r a n g e d . T h e r e f o r e , in t h i s c o n f i g u r a t i o n , t h e o p e n i n g
10 s i z e ( t h e l e n g t h o f a s i d e of a n o p e n i n g ) of each of the h o r n a n t e n n a s 5
can be s e t t o be e q u a l t o o r m o r e t h a n t h e w a v e l e n g t h of a radiated
wave ( f o r e x a m p l e , m i l l i m e t e r w a v e ) . H o w e v e r , c o n s i d e r i n g the
c o n v e n i e n c e o f t h e a c t u a l use of the a n t e n n a a n d t h e e a s e of
p r e p a r a t i o n of the a n t e n n a , t h e o p e n i n g s i z e ( t h e l e n g t h o f t h e side of
15 the opening) of each of the h o r n a n t e n n a s 5 is d e s i r a b l y set to be equal
to or l e s s than quadruple the w a v e l e n g t h o f t h e r a d i a t e d w a v e .
However, t h i s i s not i n t e n d e d t o e x c l u d e a c a s e w h e r e the opening s i z e
( t h e l e n g t h of a s i d e of a n o p e n i n g ) of each of t h e h o r n antennas 5 is
set to b e e q u a l to o r m o r e than q u a d r u p l e t h e w a v e l e n g t h of the
2 0 r a d i a t e d w a v e .
[0030]
T h e r e f o r e , a c c o r d i n g to t h e c o n f i g u r a t i o n of t h e p r e s e n t
i n v e n t i o n , the s t r u c t u r e s of the horn a n t e n n a s a n d t h e w a v e g u i d e s
leading to the korn a n t e n n a s can be e a s i l y p r e p a r e d , a n d t h u s the
25 antenna can be produced at a low p r i c e .
[003 11
'The present i n v e n t i o n i s n o t limited to t h e a b o v e exemplary
embodiments, a n d c a n be modified as a p p r o p r i a t e w i t h o u t departing
from the scope 01 t h e i n v e n t i o n . For example, t h e h o r n a n t e n n a s have
30 been d e s c r i b e d above as being the a n t e n n a e l e m e n t s , b u t t h i s is only an
e x a m p l e . For e x a m p l e , o t h e r antenna elernents such as lens antennas
and d i e l e c t r i c rod a n t e n n a s can also be u s e d . F u r t h e r , the horn
antennas each f o r n ~ e d in a cluadrangular pyramid s h a p e h a v e been
d e s c r i b e d a b o v e , but t h i s is only an e x a m p l e . F o r e x a m p l e , 11orn
11
a n t e n n a s f o r m e d i n t o o t h e r p y r a m i d a l s h a p e s such a s a cone shape, an
e l l i p t i c cone shape, and a h e x a g o n a l p y r a m i d shape c a n a l s o b e u s e d ,
as long as a d e s i r e d gain call b e o b t a i n e d . N o t only the p y r a ~ l l i d a l
s h a p e s , but a l s o a c y l i n d r i c a l s h a p e m a y b e u s e d .
5 [0032]
The w a v e g u i d e s ( t h e u p p e r w a v e g u i d e 23A, the lower waveguide
24A, t h e u p p e r w a v e g u i d e 23B, and the l o w e r w a v e g u i d e 2 4 B ) which
h a v e a f o u r - s t a g e c r a n k shape a n d c o u p l e t h e horn a n t e n n a s 5 to the
waveguide l a y e r 3 h a v e been d e s c r i b e d a b o v e , but t h i s i s only an
10 e x a m p l e . F o r e x a m p l e , t h e w a v e g u i d e s t h a t c o u p l e t h e h o r n antennas 5
to t h e w a v e g u i d e l a y e r 3 m a y h a v e a c r a n k s h a p e w i t h an a r b i t r a r y
number of s t a g e s o t h e r t h a n f o u r , as long as the r e f l e c t i o n l o s s o f radio
waves is w i t h i n a n a l l o w a b l e r a n g e . A l t e r n a t i v e l y , the waveguides that
c o u p l e t h e horn a n t e n n a s 5 to the w a v e g u i d e l a y e r 3 may be smooth
15 pipe l i n e s h a v i n g a s h a p e o t h e r t h a n a c r a n k s h a p e , a s l o n g a s the
r e f l e c t i o n l o s s o f r a d i o w a v e s i s w i t h i n a n a l l o w a b l e r a n g e .
[0033]
The arrangement of the horn a n t e n n a s 5 has b e e n d e s c r i b e d
above only as an e x a m p l e . I n s t e a d of a r r a n g i n g t h e horn a n t e n n a s 5 in
20 a s t r i c t l y s t a g g e r e d m a n n e r , f o r e x a m p l e , t h e h o r n a n t e n n a s 5 may be
arranged with a n a r b i t r a r y o f f s e t b e t w e e n a staggered arrangement and
a s q u a r e l a t t i c e a r r a n g e m e n t . The h o r n a n t e n n a s 5 need not n e c e s s a r i l y
be arranged r e g u l a r l y over the e n t i r e s u r f a c e o f t h e a n t e n n a layer 1 ,
and a p l u r a l i t y o f r e g i o n s in which the h o r n a n t e n n a s a r e o f f s e t in
25 d i f f e r e n t ways may b e p r e s e n t . In o t h e r w o r d s , t h e a n t e n n a 100
i n c l u d e s a region in which the horn a n t e n n a s 5 are arranged with an
o f f s e t to prevent the horn a n t e n n a s from being arranged in a square
l a t t i c e . t h e r e b y m a k i n g it p o s s i b l e t o s u p p r e s s the s i d e l o b e s .
[0034]
3 0 The a n t e n n a l a y e r 1 , the c o u p l i n g - p l a t e u p p e r l a y e r 21, the
c o u p l i n g - l a y e r u p p e r l a y e r 22, and t h e w a v e g u i d e layer 3 and the
b o t t o m l a y e r 4 ( w h i c h c o n s t i t u t e t h e f e e d e r c i r c u i t l a y e r 1 0 ) may be
i n t e g r a l l y f o r m e d , if they can be p r e p a r e d . For exalnple, in t h e c a s e of
p r e p a r i n g t h e l a y e r s by c a s t i n g , t h e c o u p l i n g - l a y e r u p p e r layer 21 and
12
t h e c o u p l i n g - l a y e r lower layer 22 may b e f o r m e d i n t e g r a l l y w i t h t h e
a n t e n n a layer 1 , o r t h e c o u p l i n g - l a y e r u p p e r layer 21 may b e formed
i n t e g r a l l y with t h e a n t e n n a l a y e r 1. 'I'he c o u p l i n g - l a y e r u p p e r layer 21
and the c o u p l i n g - l a y e r l o w e r l a y e r 22 may b e f o r m e d i n t e g r a l l y with
5 t h e w a v e g u i d e l a y e r 3, o r t h e c o u p l i n g - l a y e r l o w e r l a y e r 22 may b e
f o r m e d i n t e g r a l l y w i t h t h e waveguide l a y e r 3 .
[0035]
The a n t e n n a layer 1, t h e c o u p l i n g l a y e r 2 , t h e w a v e g u i d e layer 3,
a n d t h e b o t t o m l a y e r 4 may be formed, n o t o n l y o f a m e t a l , b u t a l s o of
10 a d i e l e c t r i c m a t e r i a l , s u c h as a r e s i n , the s u r f a c e o f w h i c h i s c o v e r e d
w i t h a c o n d u c t i v e m a t e r i a l such as a m e t a l . In the c a s e o f u s i n g a
r e s i n , the a n t e n n a c a n b e e a s i l y p r e p a r e d by i n j e c t i o n m o l d i n g o r the
l i k e .
100361
15 The c a s e w h e r e t h e w a v e g u i d e e n t r a n c e is formed in the bottom
layer 4 has been d e s c r i b e d above only as a n e x a m p l e . The waveguide
e n t r a n c e may b e f o r m e d , f o r e x a m p l e , in t h e w a v e g u i d e l a y e r 3.
[0037]
Although the present i n v e n t i o n has been d e s c r i b e d a b o v e with
20 r e f e r e n c e t o e x e m p l a r y e m b o d i m e n t s , the present i n v e n t i o n i s not
l i m i t e d t o t h e a b o v e exemplary e m b o d i m e n t s . The c o n f i g u r a t i o n and
d e t a i l s of t h e p r e s e n t i n v e n t i o n can be modified in v a r i o u s m a n n e r s
w h i c h c a n b e u n d e r s t o o d by t h o s e s k i l l e d in t h e a r t w i t h i n t h e scope of
t h e i n v e n t i o n .
25 [0038]
This a p p l i c a t i o n i s b a s e d upon a n d c l a i m s t h e benefit of priority
from J a p a n e s e p a t e n t a p p l i c a t i o n No. 201 3-8 172, filed o n J a n u a r y 2 1,
2 0 1 3 , t h e d i s c l o s u r e of which is i n c o r p o r a t e d herein in i t s e n t i r e t y by
r e f e r e n c e .
3 0
Reference S i g n s List
1003 91
I 0 0 ANTENNA
1 ANTENNA LAYER
2 COUPLING LAYER
3 WAVEGUIDE LAYER
4 BOTTOM LAYER
5, 51-53 HORN ANTENNAS
5 10 FEEDER CIRCUIT LAYER
2 1 COUPLING-LAYER UPPER LAYER
22 COUPLING-LAYER LOWER LAYER
23A UPPER WAVEGUIDE
23B UPPER WAVEGUIDE
10 24A LOWER WAVEGUIDE
24B LOWER WAVEGUIDE
3 1 WAVEGUIDE
25A CONNECTION END
25B CONNECTION END
15 26A CENTER OF CONNECTION END 25A
26B CENTER OF CONNECTION END 25B
27A CONNECTION END
27B CONNECTION END
14
WE CLAIM:
1. An a n t e n n a c o m p r i s i n g :
a f e e d e r c i r c u i t l a y e r in which a w a v e g u i d e e n t r a n c e and a f i r s t
5 w a v e g u i d e t h r o u g h w h i c h a radio wave is propagated are formed;
an antenna layer in which a p l u r a l i t y of a n t e n n a e l e m e n t s a r e
formed; and
a c o u p l i n g layer t h a t i s f o r m e d b e t w e e n the feeder c i r c u i t l a y e r
and t h e a n t e n n a l a y e r a n d c o u p l e s t h e f i r s t w a v e g u i d e t o t h e p l u r a l i t y
10 o f a n t e n n a e l e m e n t s w i t h a w a v e g u i d e , w h e r e i n
t h e p l u r a l i t y o f a n t e n n a e l e m e n t s i n c l u d e a f i r s t antenna element,
a s e c o n d a n t e n n a e l e m e n t , and a t h i r d a n t e n n a e l e m e n t , t h e s e c o n d and
t h i r d a n t e n n a e l e m e n t s b e i n g a d j a c e n t t o t h e f i r s t a n t e n n a e l e m e n t ,
the f i r s t a n d s e c o n d a n t e n n a e l e m e n t s a r e a r r a n g e d i n such a
15 manner t h a t c e n t e r s of the f i r s t a n d s e c o n d a n t e n n a e l e m e n t s a r e
aligned in a f i r s t d i r e c t i o n p a r a l l e l t o a p r i n c i p a l s u r f a c e of the
a n t e n n a l a y e r , and
t h e t h i r d a n t e n n a element is a r r a n g e d i n such a manner that the
! t h i r d antenna e l e m e n t i s s e p a r a t e d f r o m the f i r s t a n t e n n a e l e m e n t in a
20 s e c o n d d i r e c t i o n and c e n t e r s o f t h e f i r s t a n d t h i r d a n t e n n a e l e m e n t s are
not aligned in the s e c o n d d i r e c t i o n , t h e s e c o n d d i r e c t i o n b e i n g p a r a l l e l
to the p r i n c i p a l s u r f a c e of the a n t e n n a l a y e r a n d perpelldicular to the
f i r s t d i r e c t i o n .
2. T h e a n t e n n a a c c o r d i n g t o Claim 1 , w h e r e i n
in t h e c o u p l i n g l a y e r , a s e c o n d w a v e g u i d e that collnects t h e f i r s t
antenna element and the f i r s t w a v e g u i d e to each other and a third
waveguide that connects the third a n t e n n a e l e m e n t and t h e f i r s t
w a v e g u i d e t o each otller are formed,
a d i s t a n c e b e t w e e n a f i r s t connection end that connects the f i r s t
waveguide and t h e s e c o n d w a v e g u i d e t o e a c h o t h e r and t h e waveguide
e n t r a n c e formed in t h e f e e d e r c i r c u i t l a y e r i s e q u a l to a d i s t a n c e
between a second connection end t h a t c o n n e c t s the f i r s t waveguide and
t h e t h i r d w a v e g u i d e t o e a c h other and the w a v e g u i d e e n t r a n c e formed
15
in t h e f e e d e r c i r c u i t l a y e r ,
a c e n t e r of t h e f i r s t c o n n e c t i o n e n d a n d a c e n t e r of a third
I
conneciio-11 end t h a t c o n n e c t s the f i r s t ailtelllla elelllent and the secolld
waveguide to each o t h e r a r e s e p a r a t e d f r o m e a c h o t h e r in the f i r s t
5 d i r e c t i o n by a f i r s t v a l u e , and
a c e n t e r of the s e c o n d c o n n e c t i o n e n d a n d a c e n t e r of a f o u r t h I
c o n n e c t i o n e n d t h a t c o n n e c t s t h e t h i r d a n t e n n a e l e m e n t a n d the third
waveguide to each o t h e r a r e s e p a r a t e d f r o m e a c h o t h e r in a d i r e c t i o n
o p p o s i t e to the f i r s t d i r e c t i o n by the f i r s t v a l u e . I
10
1 3. The a n t e n n a a c c o r d i n g t o C l a i m 1 o r 2 , wherein the p l u r a l i t y ,
of a n t e n n a e l e m e n t s a r e formed in a s i z e e q u a l to o r g r e a t e r than a
w a v e l e n g t h o f a r a d i a t e d w a v e .
15 4. The a n t e n n a a c c o r d i n g to a n y o n e of Claims 1 to 3, wherein
the plui-ality of antenna e l e m e n t s e a c h h a v e a p y r a m i d a l shape with a
v e r t e x f a c i n g the c o u p l i n g l a y e r .
5. The antenna a c c o r d i n g t o C l a i m 4, w h e r e i n t h e p l u r a l i t y of
20 a n t e n n a e l e m e n t s e a c h h a v e a q u a d r a n g u l a r p y r a m i d s h a p e w i t h a
v e r t e x f a c i n g the c o u p l i n g l a y e r .
6. The antenna a c c o r d i n g to Clainl 5, wherein
o p e n i n g s o f t h e p l u r a l i t y of a n t e n n a e l e m e n t s that are l o c a t e d at
25 a s i d e o p p o s i t e to the c o u p l i n g layer h a v e a s q u a r e s h a p e , a n d
a l e n g t h o f a s i d e of the s q u a r e s h a p e is equal to o r m o r e than a
wavelength of a radiated wave.
7. The a n t e n l ~ a a c c o r d i n g t o a n y one of Claims 1 to 6, wherein
30 t h e p l u r a l i t y o f a n t e n n a e l e m e n t s are arranged in a staggered manner.
8. The a l l t c l ~ n a a c c o r d i n g t o a n y one o f C l a i m s 1 to 7, wherein
t h e s e c o n d and third w a v e g u i d e s a r e formed in a m u l t i - s t a g e crank