JPH03219706A - Planer antenna - Google Patents

Abstract

PURPOSE:To realize a planer antenna of single layer structure with high utilization efficiency by providing a ring shaped termination lot to a termination section of a radial guide path and providing a phase adjustment member giving a prescribed phase quantity in response to a circumferential angle in the vicinity of the termination section. CONSTITUTION:A ring shaped disk 44 is arranged to an outside of an outer circumferential ridge of an upper plate 40 at a prescribed interval. An opening formed between an inner circumferential ridge of the disk 44 and an outer circumferential ridge 44 of an upper plate 40 forms a termination slot 32. Then a phase adjustment member 34 giving a prescribed phase quantity in response to the circumferential angle is provided in the vicinity of the termination section in the radial guide path. The width of the member 34, i.e., a radio wave propagation distance varies with the circumferential direction and in order to avoid the reflection of the radio wave, an angle of, e.g. 45 deg. is selected to the radio wave travelling direction. Moreover, a reflecting member 50 guiding the radio wave in the direction of the slot 32 is provided to the termination part in the radial direction of a radial guide path formed by an upper plate 40 and a lower plate 42. The inner side face of the ring member of the reflecting member 50 is tilted by nearly 45 deg. to reduce the reflection toward the center.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a planar antenna, and more specifically to a planar antenna called a radial line slot antenna that is excited by an axially symmetrical mote.

[Prior art] Regarding radial line slot antennas, there are various documents (for example, Hideo Sasazawa, Makoto Ando, Naohisa Goto [Radial line slot antenna arrangement and efficiency improvement] Institute of Electronics and Communication Engineers IEICE Technical Report, AP86- 106), patent application publication No. 57-87603, 60-199201, 60
-199202, 60-199203, 60-20
No. 0602 and No. 1-46305.

The axially symmetric mode excitation planar antennas described in these publications had a two-layer structure exclusively comprising two propagation layers.

That is, a radio wave from a power source is supplied to the center of the lower propagation layer, propagated through the lower propagation layer radially outward, guided to the upper propagation layer at the outer end, and propagated within the upper propagation layer toward the center. During the propagation process in the upper propagation layer, radio waves were radiated through a large number of radiation slots. Circular polarization or linear polarization was determined by the arrangement of the radiation slots. Such a two-layer structure has the advantage that it is theoretically easy to obtain an aperture power distribution that is close to uniform with respect to the radius r in a plane along the antenna surface, but because it is a two-layer structure, it is difficult to manufacture. The disadvantage is that it is difficult.

In response to this, the inventor of the present application previously proposed a planar antenna with a single layer structure (Patent Application No. 214318 of 1999). The planar antenna disclosed in this patent application will be briefly explained. Figure 4 shows its front view, and Figure 5 shows A in Figure 4.
-A cross-sectional view along line A is shown.

In this one-layer structure planar antenna 10, a circular conductive upper plate (radiation plate) 12 and a circular conductive lower plate 14 separated by a predetermined interval form a radial waveguide for axisymmetric mode propagation. A coaxial cable 16 is connected to the center of the lower plate 12, and a transmission radio wave is supplied from the coaxial cable 16 to the radial waveguide. A matching reflector 18 is attached to the center of the inner surface of the upper plate 12 (the surface facing the lower plate 14) to direct the transmitted radio waves from the coaxial cable 16 outward in the radial direction.

The upper plate 12 has a pair of radiation slots 2OA and 20B arranged so as to be spatially and electrically orthogonal (also in the case of reception, collectively referred to as coupling slots). 20 are arranged in large numbers along a spiral line. For reference, this spiral line is shown as a broken line in FIG. It is known that when arranged in this way, circularly polarized waves can be obtained in front of the antenna (see the above-mentioned literature). In addition, various parameters of the radiation slots 2OA and 20B, specifically the lengths of the radiation slots 2OA and 20B, the distance Sr between the radially adjacent pairs of radiation slots 20, the circumferential spacing Sa, the thickness of the waveguide (i.e., the plate By adjusting the spacing between 12 and 14), the coupling coefficient α with the outside of the radial waveguide can be adjusted while maintaining the uniformity of the aperture surface electric field distribution. That is, the large number of radiation slots 2OA and 20B are arranged so that various aperture distributions can be obtained.

In the same patent application, in order to radiate all the radio waves that are not radiated to the front during the process of the feeding radio waves propagating from the center to the outer periphery to the front of the antenna, the propagating radio waves are Reflection (guidance) that directs the
The upper plate 12 is provided with a spiral slot 24 for radiating radio waves guided by the reflective material 22 to the outside. However, since it is necessary that the radio waves radiated by the slot 24 be in phase with the radio waves radiated by the slot pair 20, the slot 24 is a slot extending along the spiral line of the slot pair 20.

[Problem to be solved by the invention] As described above, the slot 24 (hereinafter referred to as
This is called a terminal slot. ) is beneficial in terms of effective use of radio waves. However, in the antenna plane, the outer part of the terminal slot 24 does not make any contribution as an antenna.
It's a wasted area.

Figure 6 shows a cylindrical coordinate system (r,
2) shows the arrangement of the radiation slot pair 20 and the termination slot 24 in the r-θ plane (i.e., the antenna plane). As can be seen from FIG. 6, the radial slot pair 20 is arranged at a radial position proportional to the circumferential angle θ, and is arranged along a reference line having a periodicity of 2π in the direction of the radius r. The terminal slot 24 also occupies a radial position proportional to the circumferential angle θ. The radius of the upper plate 12 of the planar antenna 10 is a
When the antenna is formed of a disk, the area ΔS of the shaded portion in FIG. 6 does not function as an antenna and becomes a wasted portion. For example, in the case of 12 GHz (wavelength 25 mm), the occupation ratio of ΔS ΔS/S (where S = πa 2) is 11.8% when the diameter is 40 cm, 95% when the diameter is 50 cm, and 95% when the diameter is 60 cm. In some cases, it can reach 8%.

Therefore, an object of the present invention is to provide a planar antenna that does not generate such a wasteful portion ΔS.

[Means for Solving the Problems] A planar antenna according to the present invention is a planar antenna with a single layer structure that includes a large number of radio wave coupling slots for circularly polarized waves on one side of a radial waveguide, A ring-shaped terminal slot is provided at the terminal end of the radial waveguide, and a phase adjustment member is provided near the terminal end within the radial waveguide to provide a predetermined phase amount depending on the circumferential angle.

In addition, the radial waveguide is the first one when viewed from the center in the radial direction.
comprising at least three waveguide regions, a first waveguide region having an equivalent permittivity of , a second waveguide region having a second equivalent permittivity, and a third waveguide region having a third equivalent permittivity; The second equivalent dielectric constant is larger than the first equivalent dielectric constant, and the second waveguide region gives a predetermined phase amount to the propagating radio wave depending on the circumferential angle. Preferably, matching regions are provided between the first waveguide region and the second waveguide region and between the second waveguide region and the third waveguide region.

[Function] The phase adjustment member adjusts the phase velocity of the radio wave at the end portion of the radial waveguide according to the circumferential angle. In the case of transmission, this phase adjustment causes the radio waves to have a circularly polarized phase at each circumferential angle on the concentric circle at the output position of the phase adjustment member. Therefore, the terminal slot can transmit or receive circularly polarized waves whose phase is matched with the radio wave coupling slot. Since the terminal slot may be ring-shaped or substantially circular,
There is no need to provide unnecessary flat parts on the outside.

[Embodiment] The present invention will be described in detail below with reference to the drawings. Note that the drawings attached to this specification are drawn in a somewhat exaggerated manner for ease of understanding, and the vertical and horizontal relationships are not necessarily accurate.

First, the basic idea of the present invention will be explained. In the conventional example (FIGS. 4, 5, and 6), the terminal slot 24
is extended along the extension line of the spiral line (reference line) that defines the position of the radiation slot pair 20 so that the radio waves radiated by the terminal slot 24 are in the same phase as the radio waves radiated by the slot pair 20. It is. Therefore, for example, by arranging a dielectric material that adjusts the phase velocity inside the terminal slot 24, the extension of the terminal slot 24 in the radial direction can be suppressed, and the radius a of the planar antenna can be reduced.

For example, as shown in FIG. 8, a phase adjustment made of a dielectric material whose radio wave propagation distance changes depending on the circumferential angle is located inside the terminal slot 24 and ranges from radius a-λ to radius a. Embed the material 28. λ is the wavelength. If the relative dielectric constant of this phase adjustment material 28 is ε, then the area ΔS of the outer portion of the terminal slot 24 is given by the following formula.

ΔS= (πa"-yr (a-λg)")/2a
2a However, λg=λ/fε2 Ratio of ΔS to antenna area S (=πa2) Δ
S/S changes as shown in FIG. 9 with respect to the dielectric constant ε1. From this, it can be seen that by using a dielectric material with a high relative permittivity ε2 as the phase adjustment material 28, the area ratio of ΔS can be reduced.

However, as shown in FIG.
4, it is not possible to make ΔS zero, that is, to make the terminal slot 24 circular.

Therefore, in the present invention, on the contrary, the terminal slot is first made circular, and
A dielectric material whose radio wave propagation distance changes in the circumferential angle θ direction is arranged so that even such a circular terminal slot has the same phase as the radio waves radiated by the pair of radiation slots. If the termination slot is first determined to be circular, such a phase adjustment dielectric material will also be located below the pair of radiating slots in the radial waveguide. Therefore, the positions of the radiation slot pairs are also adjusted according to the amount of phase change caused by the dielectric material for phase adjustment.

FIG. 1 is a slot arrangement diagram in the r-θ plane of an example in which a dielectric material having a relative dielectric constant ε of 4 is used as such a phase adjustment material. 30 is a radiating slot pair having two radiating slots as a pair, similar to the radiating slot pair 20 shown in the conventional example (FIG. 4); except for the outermost radiating slot pair 30, the structure is the same as that in FIG. 4. It is designed and arranged in the shape of 32 is a terminal slot that radiates radio waves not radiated by the radiation slot pair 30, and is a ring-shaped opening with an inner diameter a.

Moreover, 34 is the above-mentioned phase adjustment material (however, relative permittivity ε1=
4). This phase adjustment material 34 is connected to the terminal slot 32
The radio wave propagation distance, that is, the width, is zero at the position where the circumferential angle θ is zero in the range from the position of the radius (a-λ) to the terminal slot 32 (that is, the position of the radius a) by 2π inside from the , the width changes continuously so that the width becomes λ at a position where the circumferential angle θ is 360 degrees.

The pair of radial slots 3o on the outermost circumference are located along a reference line (spiral line) that is 2π inward from the terminal slot 32, and is located along a reference line (spiral line) that defines the pair of radial slots 30 on the inner side. ) must be located 2π outside. Further, the relative dielectric constant ε of the phase adjustment material 34
, is 4, and the wavelength λg at that part is λg;λ/'ε,=λ/2 (2) Therefore, the outermost radiation slot pair 30 is at the position where the circumferential angle θ is zero. If it is arranged on a spiral line with a radius a-λ and a circumferential angle θ of 360 degrees and a radius a-λ/2, the above phase condition will be satisfied.The phase adjustment member 34 is shown in FIG. Since it has such a position and width, and its dielectric constant ε7 is 4, the position of the pair of radiation slots 30 for one circumference of the outermost circumference can be determined mathematically and easily in this way.

2A is a front view of a planar antenna designed based on the slot arrangement of FIG. 1, and FIG. 2B is a sectional view taken along line BB in FIG. 2A. The pair of radiating slots 30 illustrated in FIG.
The terminal slot 32 and the phase adjustment member 34 are shown with the same reference numerals.

This embodiment is basically the same as the conventional example shown in FIGS. 4 and 5, except for the position of the terminal slot 32, the outermost radial slot pair 30, the terminal slot 32, and the presence of the phase adjustment material 34. It has a similar one-layer structure.

A circular upper plate 40 that constitutes an antenna surface, and the upper plate 40
A radial waveguide is formed by a parallel circular lower plate 42 spaced apart from the radial waveguide by a predetermined distance.

A ring-shaped disk 44 is arranged outside the outer peripheral edge of the upper plate 40 at a predetermined interval. An opening formed between the inner peripheral edge of the ring-shaped disc 44 and the outer peripheral edge of the upper plate 40 is
This becomes the terminal slot 32. The upper plate 40, the lower plate 42, and the ring-shaped disk 44 are made of a conductive material or a material whose surface is coated with a conductor. Although not shown, the upper plate 40 and the ring-shaped disk 44 may be connected to each other at a plurality of suitable locations in a manner and by members that do not significantly affect the antenna characteristics.

A coaxial cable 46 is connected to the center of the lower plate 42, and at the center of the inner surface of the upper plate 40 (the surface facing the lower plate 42), there is a conical matching reflection that directs the radio waves of the coaxial cable 46 radially outward. A body 48 is attached.

The width of the phase adjustment material 34, that is, the radio wave propagation distance, changes depending on the circumferential angular position as explained in FIG. 1, but as shown in FIG. 2B, in order to avoid reflection of radio waves,
The radio wave input end face and the radio wave output end face are formed obliquely, for example, at about 45 degrees with respect to the direction of radio wave propagation.

Further, a reflective (guiding) material 50 for guiding propagating radio waves toward the terminal slot 32 is provided at the radially outer terminal end portion of the radial waveguide formed by the upper plate 40 and the lower plate 42 . Since the terminal slot 32 is in the shape of a circular ring, the reflective material 50 has an inner circumferential surface of the circular ring-shaped member inclined at an angle of about 45 degrees, or a sloped surface of the reflective member 50, so that reflection toward the center is minimized. The manufacturing process is extremely simple, as it only needs to be processed into a radio wave-reflecting surface.

The inside of the radial waveguide formed by the upper plate 40 and the lower plate 42 is completely empty except for the phase adjustment material 34, but it may be filled entirely or partially with a suitable dielectric material. When filling with a dielectric material like this, the relative permittivity of the phase adjustment material 34 is determined by comparison with the equivalent permittivity of the filled dielectric material. The distance between the upper plate 40 and the lower plate 42 is maintained by the strength of the upper plate 40 and the lower plate 42 themselves, but this distance is maintained or reinforced by a suitable support member that does not adversely affect radio wave propagation. You can do it like this.

Top plate 40 has a pair of radiating slots 30 disposed therein as described in connection with FIG. Of course, as described in Patent Application No. 214318 of 1999, the lengths of the individual radiating slots constituting each radiating slot pair 30 are adjusted in the radial direction in order to obtain a practically similar aperture distribution. Distance Sr and circumferential spacing Sa between adjacent pairs of radial slots 30
, the thickness of the waveguide (ie, the spacing between the plates 40, 42), etc.

For reference, a reference line 52 (spiral line) serving as a positional reference for the pair of radiation slots 3o is shown as a broken line in FIG. 2A. Among the reference lines 52, the amount of change in the radial direction on one circumference of the outermost circumference is 1/2 compared to that on the inner circumference. This is because the relative dielectric constant of the phase adjustment material 34 is 4.

The positional relationship between the reference line 52 (spiral line) of the radiation slot pair 30, the terminal slot 32, and the phase adjustment material 34 is illustrated in FIG. The phase adjustment material 34 is hatched. In FIG. 3, the end face shape of the phase adjustment material 34 in contact with the upper plate 40 is illustrated. In order to facilitate understanding, the phase adjustment material 34 is illustrated with hatching. The inner end face of the phase adjustment member 34 is circular with a radius of a-λ, and the outer end face is a spiral line whose radius changes from a-λ to a.

The operation of the planar antenna shown in FIGS. 2A and 2B will be briefly described. A radio wave signal from a radio wave source (not shown) is supplied via a coaxial cable 46 into a radial waveguide formed by an upper plate 40 and a lower plate 42, and is directed radially outward within the radial waveguide by a matching reflector 48. and propagate. During this propagation process, the radiation slot pair 30 gradually radiates circularly polarized radio waves to the front of the antenna. In the outermost pair of radiation slots 30, the phase adjustment material 34 emits radio waves whose phase is adjusted to be the same as the phase of the radio waves radiated by the innermost pair of radiation slots 30. The radio waves that are not radiated by all the radiation slot pairs 30 pass through the phase adjustment material 34 with almost no reflection, are directed toward the terminal slot 32 by the reflection material 50, and are radiated to the front of the antenna. The radio waves that have passed through the phase adjustment material 34 are circularly polarized radio waves on concentric circles centered on the antenna center. Therefore, the radio waves radiated from the terminal slot 32 are circularly polarized waves due to the radiation slot pair 30. completely in sync.

In the embodiments described in FIGS. 1, 2A, 2B, and 3, the inner end surface of the phase adjustment member 34 is circular with a radius a-λ, and the outer end surface has a radius from a-λ to a. Although the shape is a spiral line in which the shape changes, other shapes may be used. FIG. 1θ shows the same r-
FIG. 3 is a slot arrangement diagram in the θ plane. 60 is a radiating slot pair similar to the radiating slot pair 30; 62 is a terminal slot 32;
Similarly, the circular ring-shaped terminal slot 64 is a phase adjustment material corresponding to the phase adjustment material 34. In this embodiment, the phase adjustment material 60 has a dielectric constant of 4, and its inner end surface ranges from a (circumferential angle θ=0) to aλ (circumferential angle θ=0).
It is a spiral wire whose radius changes to 360), and the outer end face is circular with radius a.

In this case, the outermost radial slot pair 60 has a radius of a-λ(θ=0) to a-λ/2(θ=180)i, in the range of circumferential angle θ from 0 degrees to 180 degrees. They may be arranged along a changing spiral line, and if the circumferential angle θ is in the range of 180 degrees to 360 degrees, they may be arranged along a circle with a radius of a−λ/2.

In the above embodiment, a dielectric material with a dielectric constant of 4 was used as the phase adjustment material 34.64, but this is just an example, and it is clear that materials with other dielectric constants may be used. be. Further, in the above embodiment, the inner end surface and outer end surface of the phase adjustment material 34.64 are curved surfaces whose radial position changes smoothly with the circumferential angle, but of course, one or both of them may be approximated by a polygonal shape. You can. Furthermore, the phase adjustment material 34.6
The phase amount at one circumferential angle may be changed by changing the dielectric constant or by changing the radio wave propagation distance and the dielectric constant.

In the above embodiment, the case where radio waves are radiated in front of the antenna has been described as an example, but the present invention can of course be applied to a beam tilt type antenna in which radio waves are radiated obliquely at a predetermined angle from the front of the antenna. For example, as shown in FIG. 11, when the front side of the antenna is the Z axis and the x and y axes are arranged on the antenna surface, the main beam is set at an angle φ from the two axes in the yz plane. Let's consider the case where it is tilted a lot. The condition that the radio wave emitted from the origin O (virtual wave as a reference) and the radio wave emitted while propagating from the origin O to two points are in phase in the main beam direction is 2πrn
/λg −2yr r 1.1cosa /λ2 (n
+C) π10θ (3) However, C is a constant, n
is a positive integer that is 01 for the innermost spiral and N for the outermost spiral.

cos a = sinφosinθ
(4) Therefore, from Equation (5), a pair of radiation slots similar to pair 20.30 of radiation slots is arranged so that it is farther from the center in the +y-axis direction and closer to the center in the -y-axis direction. I know what to do. Furthermore, from equation (6), it can be seen that the spiral spacing does not depend on n. FIG. 12 shows the slot arrangement on the antenna plane in such a case.

In such a beam tilt type antenna, when the invention of Patent Application No. 214318 of 1999 is applied to the pair of radiation slots to provide a termination slot, the termination slot is also curved along the same reference line as the pair of radiation slots. Just let it happen. The arrangement of the terminal slot and the radiation slot pair in the r-0 plane in the case of the beam tilt type is shown in FIGS. 13 and 14. Note that, for the sake of simplicity, these illustrations assume that the tube wavelength λg is equal to the spatial wavelength λ. Figure 13 shows the inclination angle φ. =15°, and FIG. 14 shows the case where the inclination angle φ. ;
The case of 5° is shown. Basically, as can be understood from the above description, the portions at the circumferential angle θ=90° or 270° may be arranged along curved lines that swell in mutually opposite directions. In FIG. 13, numerals 70 and 72 indicate reference lines for arranging pairs of radial slots, and numeral 74 indicates terminal slots. In FIG. 14, reference numerals 76 and 78 indicate reference lines for arranging pairs of radial slots, and numeral 80 indicates terminal slots.

FIG. 15 shows a slot arrangement diagram in the r-6 plane when the present invention is applied to the beam tilt type planar antenna of FIG. 14. Reference numerals 82, 84, and 86 indicate the pair of radiation slots 30.
indicates a reference line on which a pair of radial slots corresponding to is placed;
Reference numeral 88 indicates a terminal slot. Further, reference numeral 90 indicates a placement reference line for the pair of radial slots, assuming that the terminal slot 88 is placed further outside. Reference line 82.8
4 coincide with reference lines 76 and 78 in FIG. 14, respectively.

Reference numeral 92 denotes a phase adjustment material disposed inside the terminal slot 88 to make it a perfect circle or a substantially perfect circle;
As in the case of FIG. 1, a dielectric material with a dielectric constant ε of -4 is used, and the other parts are spaces (relative permittivity ε2=1). The inner diameter of the phase adjustment member 92 is constant, and the outer diameter changes in the circumferential direction. That is, the change in the circumferential angle of the outer diameter is a curve obtained by shifting the reference line 90 inward. The reference line 86 extends along the outer peripheral edge of the phase adjustment material 92, and when θ is in the range of O to 180°, the phase adjustment material 9
The phase adjustment member 92 is located on the outer side of the outer circumference of the phase adjustment member 92, and is located on the inner side of the outer circumference of the phase adjustment member 92 in the range of 180 to 360°. The positions of the reference line 86 and the outer circumferential end of the phase adjustment member 92 may be basically designed using the same concept as explained in connection with the embodiment of FIG. 1.

Next, a modified embodiment regarding phase adjustment inside the terminal slot will be described. In general, the radio wave propagation situation of a waveguide structure in which materials are laminated that are sufficiently thin and have different dielectric constants compared to the wavelength in the lateral direction of radio wave propagation, and in which the lateral width of the waveguide changes in the radio wave propagation direction is determined by the equivalent dielectric constant. This can be explained theoretically by the following, and the matching condition at an interface where the equivalent permittivity changes is also known.

Therefore, in the present invention, the phase adjustment function of the phase adjustment materials 34, 64.92 is realized isometrically by providing a plurality of dielectric layers in the radial waveguide and adjusting the width of the waveguide. Good too.

FIG. 16 shows a front view (a), a central vertical cross-sectional view (b), and a central cross-sectional view (C) of the modified embodiment.

However, in the front view shown in FIG. 16(a), illustration of the radiation slot pair is omitted. Reference numeral 100 is a slot plate having a large number of radiating slot pairs corresponding to the radiating slot pair 30, and corresponds to the upper plate 40 in FIG. Further, 102 is a base plate for forming a radial waveguide with the upper plate 100, and corresponds to the lower plate 42 in FIG. 104 is a coaxial cable. 106 is a perfectly circular or substantially perfectly circular terminal slot, which is similar to the terminal slot 32 (FIGS. 1 and 2A).
and FIG. 2B). Excitation radio waves by the coaxial cable 104 propagate radially outward through a radial waveguide formed between the slot plate 100 and the base plate 102, and are transmitted through a pair of radiation slots (not shown) and a terminal slot 1.
06 to the outside.

In the radial waveguide formed by the slot plate 100 and the base plate 102, a dielectric plate 108 whose outer diameter increases in a spiral shape according to the circumferential angle is arranged. That is, if the radii of θ=0°, 90°, 180°, 270°, and 360° are respectively old, R2, R3, and R4, then RO<
R1<R2<R3<R4. Although details will be described later, the portion of the dielectric plate 108 outside the radius RO substantially functions as the phase adjustment material 34.

The thickness of the dielectric plate 108 is constant, and its peripheral end face is cut off at right angles. In order to easily understand the shape of the dielectric plate 108, the dielectric plate 108 is illustrated with hatching in FIG. 16(a).

The dielectric plate 108 can be formed, for example, by punching out a plate material formed by mixing or combining a plurality of synthetic resins, and one having a dielectric constant of about 4 to 6 can be easily and freely obtained.

There is a space 110 between the dielectric plate 108 and the base plate 102 in a region from the center to a certain radius Rs, and the dielectric plate 1
Radio waves propagate according to the equivalent permittivity determined by the permittivity of the space 110 and the permittivity of the space 110.

Although the details will be described later, just before the radius Rs, the space 11 is
The width of the space 110 is gradually narrowed, and eventually the width of the space 110 is made zero, probably for the purpose of supporting the dielectric plate 108. Outside the radius Rs, the radio waves are made to propagate only through the dielectric plate 34 during the radio wave propagation distance necessary for the phase adjustment material 34, and further outside of that, depending on the matching conditions, there is no reflection or even a small amount of reflection. The width of the radial waveguide is set so that The radio waves passing through the dielectric plate 108 are in space 1
12, reaches the terminal slot 106, and is radiated to the outside.

With reference to FIG. 17, the radio wave propagation conditions in the vicinity of the radius Rs will be briefly explained. For simplicity, a plane wave approximation is used. FIGS. 17(a) and 17(b) show cross-sectional views of the waveguide region where phase adjustment is performed.

Figure 17(b) corresponds to the structure in Figure 16, and the first
The object of the present invention can be achieved with either of FIGS. 7(a) and 7(b). 17(a) and 17(b) can be considered to be transmission lines as shown in FIG. 17(C). That is, the first
Region I in Figure 7(C) is each region I in Figures 17(a) and (b).
Corresponding to regions a and Ib, region 2 in FIG. 17(C) corresponds to each region IIa in FIGS. 17(a) and (b).

Corresponding to mb, area ■ in Fig. 17(C) corresponds to Fig. 17(a
) and (b), respectively, correspond to areas ma and mb.

The impedance 2 of the transmission line is generally Z = V / 1 = Ed / (Hw) = ηd / w = dzo / rε, (7) where W is the width of the line (constant), d is the height of the line, ε8 is the equalized dielectric constant of the line. Further, the wave number is k = k 0jε, (8).

Therefore, assuming that the dielectric constant of the dielectric plate 108 is ε1, its thickness is dI, the area ma is, and the width of the radial waveguide in llIb is d3, as shown in FIGS. 17(a) and (b).
In regions Ia and Ib, Zr=d, Z0/rε, (9) kt=0v”εr (10)
In the areas ma and llIb in FIGS. 17(a) and (b),
Zi=dsZ, (11)k
,=to, (12). In region IIa of FIG. 17(a), Z,=dZ,
(13) k,=to,
(14). In region nb of FIG. 17(b), Z 2= d 3Z o/ r ε#2
(15) k2=kl, rε-t
(16) However, this is due to the concept of series connection of capacitors.

The voltage and current in each region are as follows. That is, area I
a, Ib, 'b=AZs (exp(-jk+z)+Rtexp(
jk+z)l (18)1,=Afexp(-jk
+z)-R+exp(jk+z)l (19) In areas na and IIb, V+=BZdexp(-jksz)+Rtexp(jk
zz)l (20)It=Bfexp(-jk2z
)-Rzexp(jksz)l (21) Region II
In Ia, mb, Vs” CZseXp(-jksZ)
(22) Is=Cexp(-jksz)
(23). At the point where 2=0, that is, the boundary between areas Ia and Ib and areas IIa and Ilb, z=a, that is, areas IIa and IIb and area II
[a.

At the boundary of mb, 1-Rsexp(j2θ) where θ= and a. From equation (25), we get Zs+L, and by substituting this into equation (24), we get 1+R+
Z2 Z3+Z2+(Z3-Z2)exl)(-
J2θ)14+ ZI Z3+22-(Z3-
Z2) expC-J2θ) (27) is obtained. Assuming that there are only radio waves propagating outward in the radial direction in regions Ia and Ib, R,=O(2g), and substituting this into equation (27), the matching condition is θ=π/2 (2
9) L2: ZlZs
(30). So that this is satisfied, d+
+dl-ε1°a may be selected.

To give a specific numerical example, in the case of FIG. 17(a), when the length a of the area Ua is λ/4 from equation (29), there is no reflection, and in the case of 12 GHz, a= λ/4=6.25
mm, and from the matching condition of equation (30), (dl Z O,) 2= d, d, Z , 77 E
I (31) Therefore, d, /d, = v - ε1 (32) and if ε1 = 4, ds/ dl = 2 (3
3).

In addition, in the case of FIG. 17(b), (asZo/"ε-2)"= dldl Z 6"/
rεl (34), so d,=(ε,2/fε1) a (35
) From this and equation (17), d, = d, + (rεl-1)d/ε, (3
6) ε, 2=(ε1+``εt-1)/V-ε1 (
37) is obtained. Here, if ε1=4, da=
(5/4) dx (38)ε
. 2 = 2.5 (39), and at 12 GHz, a = λ/(4fε, 2) = 3.95 mm (40
).

Although FIGS. 16 and 17 illustrate the case where one dielectric plate 108 and the air layer 110 are laminated, the present invention is of course not limited to this combination, and a plurality of layers may be laminated or By changing the width of the waveguide, the phase adjustment material 34,
The same phase adjustment effect as in 64.92 may be achieved. In such a waveguide structure, it is not so difficult to suppress or eliminate reflection at the portion where the permittivity changes in the radio wave propagation direction, and the shape and dimensions of the matching region are also similar to the above example. Not limited. Further, as shown in FIG. 2B, when the end face of the phase adjustment material 34 is formed obliquely,
However, the embodiment shown in FIG. 16 is very simple to manufacture and can be manufactured at low cost.

Although the case of emitting radio waves, that is, the case of transmission, has been explained as an example, the same argument holds true in the case of receiving radio waves due to the antenna reciprocity theorem. The claims should also be understood accordingly. In addition, the radiation slot pair 30 in this specification
．． 60 radiating slots and termination slots 32, 62, 1
06 may be an aperture for radio waves, and does not need to be a physical aperture.

[Effects of the Invention] As can be easily understood from the above description, the present invention can provide a single-layer planar antenna with high utilization efficiency of the antenna surface. In other words, a smaller planar antenna can be provided.

[Brief explanation of drawings]

FIG. 1 is a slot arrangement diagram in the r-θ plane of an embodiment of the present invention, FIG. 2A is a front view of a planar antenna designed according to FIG. 1, and FIG. cross section,
FIG. 3 shows the phase adjustment material 34 of the antenna shown in FIG. 2A.
Figure 4 shows the shape of the previous patent application No. 214 of 1999.
Front view of the single-layer planar antenna described in No. 318, No. 5
The figure is a cross-sectional view taken along line A-A in Figure 4, Figure 6 is a slot arrangement diagram on the r-θ plane of the planar antenna in Figure 4, and Figure 7 is the characteristic of ΔS/S in the plane antenna in Figure 4. FIG. 8 is a slot arrangement diagram in the r-θ plane for detailed explanation of the present invention, and FIG.
The figure is a characteristic diagram of ΔS/S with respect to Figure 8, Figure 10 is a slot arrangement diagram on the r-θ plane of another embodiment of the present invention, and Figure 11 is an explanatory diagram of the coordinate system of the beam tilt type planar antenna. , FIG. 12 is a front view of the beam tilt type planar antenna, and FIG. 13 is the inclination angle θ. Figure 14 shows the slot arrangement on the r-θ plane when = 15° is the inclination angle θ. Fig. 15 is a slot arrangement diagram in the r-θ plane when the present invention is applied to a beam tilt type planar antenna, and Fig. 16 is a diagram showing the slot arrangement in the r-θ plane when = 5°. A front view, a vertical cross-sectional view, and a cross-sectional view of another configuration for realizing the function of the member 34.64. FIG. 17 is an example of the cross-sectional structure of the phase adjustment portion of FIG. 16. 30.60: Radiation slot pair 32.62: Final f[1i
ii Slot 34.64: Phase adjustment material 4o: Upper plate 4
2: Lower plate 44: Ring-shaped disc 46: Coaxial cable
48: Matching reflector 50: Reflector 52: Reference line (spiral line) 74, 80.88=Terminal slot 92
: Phase adjustment material 100 Nislot plate 102: Base plate 104: Coaxial cable 106: Termination slot 10
8: Dielectric plate 110.112: Space

Claims (3)

[Claims] (1) A planar antenna with a one-layer structure that has a large number of radio wave coupling slots for circularly polarized waves on one side of a radial waveguide, in which a ring-shaped terminal slot is provided at the end of the radial waveguide, and Near the end of the waveguide,
A planar antenna comprising a phase adjustment member that provides a predetermined phase amount depending on a circumferential angle. (2) A planar antenna with a one-layer structure that has a large number of radio wave coupling slots for circularly polarized waves on one side of a radial waveguide, in which a ring-shaped terminal slot is provided at the end of the radial waveguide, and The waveguide has a first waveguide region having a first equivalent permittivity, a second waveguide region having a second equivalent permittivity, and a third guide region having a third equivalent permittivity, viewed from the center in the radial direction. The wave region includes at least three waveguide regions, the second equivalent permittivity is larger than the first equivalent permittivity, and the second waveguide region has a predetermined phase amount according to a circumferential angle. A planar antenna characterized by giving propagating radio waves. (3) The radial waveguide is provided between the first waveguide region and the second waveguide region and between the second waveguide region and the third waveguide region, respectively. The planar antenna according to claim 2, further comprising a matching region.