JPH0449704A - Small antenna spatial matching system - Google Patents

Abstract

PURPOSE:To use plural rectangular ridge waveguides as antenna elements and to attain a wideband and miniaturization by arranging three kinds of dielectrics provided with high-pass matching characteristic, low-pass matching characteristic, and low-pass and middle-pass matching characteristic sequentially. CONSTITUTION:A first dielectric A 11a provided with the high-pass matching characteristic at the outside is arranged on the plane of the aperture part 16 of the rectangular ridge waveguide 10a, and a second dielectric 12 provided with the low-pass matching characteristic and furthermore, a third dielectric 13 provided with the low-pass and middle-pass matching characteristic adhering on the plane of the aperture part 16 are arranged at the intermediate part. Therefore, impedance matching between the waveguide 10a and free space can be performed extending over the wideband >= one octave. Furthermore, integral fixture can be realized by forming the outside shape of the three kinds of dielectrics 11a or 11b, 12, and 13 in the same shape as that of the aperture part 16, and forming the dielectric 13 in flat plane shape, and forming the dielectric 12 in hollow structure, and employing the fit-in structure with the dielectric A 11a or the dielectric B 11b.

Description

[Detailed Description of the Invention] (Summary) Regarding a small antenna spatial matching method using three types of dielectric materials, a broadband phased array antenna that is subject to severe restrictions on the arrangement pitch of antenna elements and an electric field that requires miniaturization. The r-1 purpose is to provide a measurement probe, and in a device using a plurality of rectangular ridge waveguides as antenna elements, a first dielectric material A and a second dielectric material A are provided on the opening surface of the ib-shaped ridge waveguide. Three types of dielectrics are arranged in the order of a dielectric and a third dielectric, and the third dielectric is provided in close contact with the opening, and further, the first dielectric A has a high frequency matching characteristic, The second dielectric in the middle has low frequency matching characteristics, and the third dielectric (13) in close contact with the opening surface has low and middle frequency matching characteristics, and the rectangular ridge waveguide The structure is such that impedance matching can be performed over a wide band of 1'A-tabe or more between the 1'A vector and the free space.

Further, the rectangular ridge waveguide is configured to be a circular ridge waveguide.

[Industrial application field]

The present invention relates to a small antenna spatial matching method using three types of dielectric materials.

[Conventional technology]

FIG. 5 is a diagram showing the configuration of a rectangular ridge waveguide, which is a double ridge waveguide. In the figure, 51 is the first ridge, 52
is the second ridge.

As shown in Fig. 5, a normal glue-solid waveguide has a horizontal dimension in the tube on the long side side of a, a vertical dimension in the tube on the short side side as b, and a first ridge of a conductor with a width of W on the internal long side. 51 and a second ridge 52 are provided at intervals to obtain a required characteristic impedance, passband frequency, etc.

Usually, the characteristic impedance Zr of the ridge waveguide is the characteristic impedance Zo (Zo = 377Ω) of free space.
In particular, the characteristic impedance Zr in the case of a double ridge waveguide is generally around 200Ω. Therefore, if the ridge waveguide is opened to space as it is, the radiation efficiency of electromagnetic waves from the ridge waveguide to free space will be low due to the mismatch between the characteristic impedances of 200Ω and 377Ω.

Moreover, while maintaining the frequency band, the inner dimensions of the ridge waveguide a,
b at the lower operating limit frequency fL as λL/4(λL −C
/fL, C is the speed of light), the characteristic impedance Zr will be approximately 173 (approximately 120 Ω) or less than the characteristic impedance Zo of free space, and the electromagnetic wave will flow into free space when the ridge waveguide is open. The radiation efficiency is extremely low.

Examples in which an antenna is formed using a twisted waveguide having such characteristics are shown in FIGS. 6 to 8.

Figure 6 is a structural diagram of an example of a double ridge horn antenna.
FIG. 7 is a structural diagram of another example of a double ridge horn antenna, and FIG. 8 is a structural diagram of an example of an antenna using a thin film and a dielectric material in the opening 11 of the double ridge waveguide.

Conventionally, for impedance matching between a ridge waveguide and free space, the following methods are used: 0) i1 method a', b of the opening 64 of the ridge waveguide
' is made wider than the inner dimensions a and b of the Mj-shaped ridge waveguide, and the first ridge 61 and second ridge 62 of the opening 64 at the tip are made into a tapered shape.

(See Figure 6) (2) Make the internal dimensions a and b of the ridge waveguide slightly larger than the specified internal dimensions of the waveguide, and In between, the heights of the first ridge 71 and the second ridge 72 are gradually reduced.

(See FIG. 7) (3) A structure is created in which aluminum, copper, or the like is layered on the inside of the opening 84 of the ridge waveguide, a metal thin film 81 is layered on the inside, and a dielectric material 82 is layered on the outside to achieve impedance matching.

(See Figure 8). but,! 11 widens the aperture size of the ridge waveguide to facilitate impedance matching, but the aperture 640 size becomes larger. In addition, in (2), the area ratio is 1.5 to 2 times larger than that of a normal ridge waveguide, but broadband impedance matching cannot be obtained for a ridge waveguide with a size of about λL/4. do not have. Note (3)
When the shape is made smaller, wide-range impedance matching cannot be achieved because the impedance variation range is large.

In general, miniaturization of antennas and broadbandization are contradictory technologies. In particular, the lower the lower limit frequency is, the more miniaturization becomes possible.

FIG. 9 shows the configuration of a phased array antenna. 9th
An antenna element 90 in the figure is a plurality of antennas shown in FIGS. 6 to 8 arranged in series on a plane.

Generally, in a phased array antenna, if the distance between the antenna elements (1qd) does not satisfy the following conditions, an unnecessary beam (referred to as a grating and at the same level as the main beam) will be generated in the direction beyond the main beam. In the linearly arranged phased 7-ray antenna shown in the figure, the condition for the arrangement interval d to prevent generation of unnecessary beams is given by C.

Here, λH: c/(a) (C is the speed of light) fH: Operating upper limit frequency 10: Beam scanning range 2 As shown in (1), the interval d becomes smaller as λ8 becomes smaller (the frequency becomes human) If the frequency band is to be secured for this reason, the shape and dimensions of the antenna will be restricted.

For example, frequency band 2:1. Arrangement pitch d of linear array that does not generate unnecessary beams when the beam scanning range is 30°
is d=0.67λ, =0.332. How should it be set, and the antenna element is forced to be miniaturized?

[Problem to be solved by the invention]

Therefore, there are problems in that the antenna elements of phased array antennas with higher bandwidths are subject to significant restrictions in terms of dimensions, and impedance matching of antenna elements becomes more difficult as the bandwidth becomes wider.

SUMMARY OF THE INVENTION An object of the present invention is to provide a broadband phased antenna that is subject to severe restrictions on the array pitch of antenna elements, and an electric field measurement probe that requires miniaturization.

[Failure to solve the problem]

The present invention uses a plurality of rectangular ridge waveguides 1Oa as an antenna element, in which the rectangular ridge waveguide 1Oa
The first dielectric A, the second dielectric 12, and the third dielectric 13 of 11a are arranged in the order of 31! The third dielectric 13 is provided in close contact with the opening 16, and the first dielectric A of the first dielectric 11,1 has a high frequency matching characteristic, The dielectric 12 has a low-frequency matching characteristic, and the third dielectric 13, which is in close contact with the surface of the opening 16, has a low- and middle-frequency matching characteristic. The configuration is such that impedance matching can be performed over a wide band of one octave or more between the two.

Further, the rectangular ridge waveguide 10a is configured to be a circular ridge waveguide 10b.

[For production]

In the present invention, in the configuration shown in FIG. 1, the first dielectric material A of 11a having high-frequency matching characteristics is disposed on the outside of the opening 16 of the rectangular ridge waveguide 10a, and the first dielectric material A of 11a having high-frequency matching characteristics is disposed in the middle. A second dielectric 12 having matching characteristics is provided, and the opening 1
A third dielectric material (
13) are installed.

Therefore, impedance matching is possible over a wide band of one octave or more between the rectangular ridge waveguide 10a and free space.

Furthermore, by replacing the rectangular ridge waveguide 10a with the circular ridge waveguide 10b shown in FIG. 2, the same characteristics as those obtained when the rectangular ridge waveguide 10a is used can be obtained.

Furthermore, each of the three types of dielectrics 11a or 11b, 12.1
30 has the same external shape as the opening 16, the third dielectric 13 has a flat plate shape, and the second dielectric 12 has a hollow structure, so that the first dielectric A of the 11a or l l b
It has a structure in which it fits with the first dielectric material B, thereby making it possible to fix the body layer.

〔Example〕

FIG. 1 is a diagram showing the configuration of the present invention, and the case of a rectangular ridge waveguide will be described. FIG. 2 is a diagram showing the configuration of an embodiment of the present invention, and the case of a circular ridge waveguide will be described. In addition, in Figures 1 and 2, fa)
is an exploded perspective view, fbl is a plan view of main parts (part 1), (
C) is a principal part plan view (part 2), and (d) is a sectional view taken along line AA'. Furthermore, FIG. 3 is a diagram showing a detailed structure of an embodiment of the present invention, and corresponds to FIG. 2 described above. and,
FIG. 4 is a diagram showing the detailed structure of another embodiment of the present invention, which is a modification of FIG. 3.

In the figure, 10a is a rectangular ridge waveguide, and lOb is a circular ridge waveguide. Moreover, 11a (or 11b) is a first dielectric material A (or first dielectric material B) for high frequency matching,! 2 is a second dielectric for low frequency matching, and 13 is a third dielectric for low to middle frequency matching. Note that 14 is a first ridge, 15 is a first ridge, and 16 is an opening. Furthermore, 17 is a screw for fixing the dielectric, 1) 3 is a screw, a fixing hole, and 19 is a through hole 1.20.
2 is an electric field wall, 21 is a domain wall, and 22 is a cutting portion.

Figure 1 shows the entire circumference of the antenna for implementing a horizontal array antenna 7. In order to avoid sudden impedance changes between the rectangular ridge waveguide 10a and the free space, three types of antennas 11a are used. The m-th electric body A (or the first dielectric B of 11b), the 74th dielectric 12, and the first dielectric 13 are used.

As shown in FIG. 1a), the rectangular ridge waveguide 10a is a double ridge type, and has internal dimensions a and b.

//4 to 1mi, basic mode 1゛E,. The inner dimension a of the rectangular ridge waveguide 10a is adjusted so that the cutoff frequency of 0.8 to 0.9 fL (fl is the lower limit frequency of operation).
, bw, h. This rectangular ridge waveguide 10
The characteristic impedance Zr of a is about 173 to 1/4 of the characteristic impedance Zo of free space. First ridge 1 on the mouth 16 side of the TIi type bridge waveguide 10a
4 and the tips of the second ridge 15 are slightly partially shaved off in order to achieve impedance matching with the free space.

The configurations of the first dielectric A of these three types 11a (or the first dielectric B of 11b), the second dielectric J2, and the third dielectric 13 are shown in FIG. 1(a), (lil, (C ), the third dielectric 13 is brought into close contact with the opening 16,
In addition, the first dielectric A of 1.1a (or the first dielectric B of 11b) and the third dielectric 13 are arranged such that the second dielectric 12 is in the center and the third dielectric 13 is inside, and the third dielectric 13 of 11a is -F electric body A (
Or have a fitting structure in which the first dielectric B) of 11b is on the side. The first dielectric A of 11a (or the first dielectric B of 11b), the second dielectric 12, and the second dielectric 13. have different dielectric constants, and the first dielectric A of 11a (or 11b
The relative permittivity ε1 of the first dielectric material B) is set to a low value7,
The relative permittivity ε3 of the third dielectric 13 is set to a high value, and the relative permittivity ε of the second dielectric 12 is set to an intermediate value between ε1 and ε3 (
Set to ε, kuεzkuε3).

Note that fixing of the first dielectric A of the three types of dielectrics 11a, the second dielectric 12, and the third dielectric 13 is as follows.
The first dielectric A and the second dielectric 12 of a are fitted and fixed 2, and the first dielectric Δ of 11a, the first dielectric 12, the third dielectric 13, and the third dielectric 13 are rectangular. The identification with the ridge waveguide 1 (l it ) is, for example, by adhesion.

In Fig. 2, the entire antenna is designed to improve the element arrangement of the phase 1 antenna even more than when the one shown in Fig. 1 is used for the J, -=Z1 array antenna. It has a circular circumference.

The structure of the ridge waveguide is a circular 7-D waveguide structure in which the domain wall inside the waveguide is rounded and the domain wall inside the waveguide is rounded. The opening 16 of the circular ridge waveguide 10b is
Considering the fixation of the first dielectric A of three types 11a (or the first dielectric B of 11b), the second dielectric 12, and the third dielectric 13, the outside of the circular ridge waveguide 10b and Domain wall 21 inside circular ridge waveguide 10b. 1, and 3 types of 11a's first dielectric A (or 11[]'s first dielectric B
B, the second dielectric 12, and the third dielectric 13 have a circular structure. In addition, the first dielectric material A of three types of 11a (
Or the opening of the circular ridge waveguide 1011 of the first dielectric B) of 11b, the first dielectric 12 and the third dielectric 13 ■
6 is fixed using the screw 17, the screw hole 18, and the through hole 1.
9. In this case, Fig. 2(a), +1))
, fc), +d+, the cut portion 22 on the side of the electric field wall 20 of the open L1 portion 16 of the circular waveguide 10b is cut off to become a flat surface, and three types of 11a are cut out.
A space for mounting the first dielectric Δ (or the first dielectric 113 of 11b), the near dielectric 12, and the third dielectric 13 is secured. A circular ridge waveguide 1. Hole 18 is drilled 5-☆ to prevent screw 17 from being inserted inside Ol:+. I decided to have a structure like this. 11 of three types of round ridge waveguide 10b-=
The first dielectric A of a (or the first dielectric B of 11b), the second dielectric 12 and the third dielectric 13 can be securely fixed, and the element arrangement of the phased array antenna can be improved. It is possible to make people look towards you.

Fig. 3 (Here, the dimensions 7!i1.!!3□ of the rounded shape of the circular ridge waveguide 10b are 91 x 5 mm, the operating limit frequency f, and the odor l: 11 are 0.24λLmm.
, #32 is 0.16λ), the modified circular ridge waveguide 1 Ol::+, the first dielectric A of 11a (or the first dielectric B of 11b) of three types, and the first dielectric B of 11b. dielectric 1
2 and 9 and a third dielectric 13. Also the first
The width W of the first ridge 14 and the first ridge 15 is 2 cm, the interval is 0.5 to 0.6 cm, and the frequency band is 8 to 6 cm.
It is 18GHz.

, : Here, the value of the cutoff frequency of the circular ridge oil guide pipe 10b is:
Basic mode TE, fcl in O. =6.7 G Hy,
, f Czo = 45G H at high order dryness - r′I″E20
It is z. The characteristic impedance Zr of the circular ridge waveguide lOb is 130 at 8 and 18 GHz, respectively.
Ω and 78Ω. The first dielectric A, second dielectric 12, and third dielectric 13 of 11a have the characteristic impedance Zr.
is used to match the characteristic impedance Zo (Zo −377) of free space over a wide band of 8 to 18 C”, I Hz. By changing the thickness of the antenna, the width of the antenna can be changed without deteriorating the standing wave ratio (hereinafter also referred to as VSWR) within the frequency band.With this configuration, the width of the antenna can be changed using the circular ridge waveguide 10b. The external dimensions I and o of the antenna element are 10 mm in diameter.
(0,27λ1.). Note that the first dielectric material A of 11a
The length is 7! i15 is 2 “”” 511111,7!
:16 is 4×5 mm, and the thickness el of the third dielectric 13 is 0.5=-0.8 mm. The second dielectric 12 and the third dielectric 13 are fixed to the second dielectric of Ila using two screws 17.

According to this embodiment: 1. From (1) 2 above, it becomes possible to realize a phased antenna whose scanning range exceeds ±306 in the same frequency band.

The actual measured values are as follows: VSWR-=-=-2: Antenna gain of 1 or less -0aBi or more <taax 7 d 1
3 i) Beam width -=70 to 150 In Fig. 4, the shape of the first dielectric 11a in Fig. 3 is changed to the first dielectric 11b, and its characteristics are almost the same as those in Fig. 3. are the same.

As a supplementary explanation, for this type of ridge waveguide, if the opening of the waveguide is covered with one type of dielectric and impedance matching is achieved, the matching frequency will be approximately one octave. It is extremely difficult to obtain (VSWR281
frequency band of species degree).

Furthermore, when the opening of the waveguide is covered with a dielectric material such as 2-4, a frequency band of approximately 1 octave may be secured by appropriately selecting the shape, dielectric constant, etc. In this case, the size of the dielectric at the opening of the ridge waveguide increases and the surrounding force of the Lj section between the solid waveguides becomes large, resulting in restrictions on the element arrangement of the phased array/f antenna (
That is, even if the waveguide glue (・1 is made as small as possible and 2 is
Since the outer dimensions of the dielectric become larger, there are cases where it becomes impossible to obtain the desired arrangement pitch. ).

However, by adopting the features described in Figures 1 to 4 and according to the present invention, the outer dimensions of the waveguide and the dielectric body = j- can be made the same, so that the elements of the phased array antenna can be Arrangement constraints can be greatly improved.

In addition, as the dielectric array becomes smaller (that is, the distance between the dielectrics of each antenna element of the fez array antenna becomes larger), the phase generated due to the proximity of each antenna element! - The interference (mutual coupling) can also be reduced.

〔Effect of the invention〕

As is clear from the following explanation, according to the present invention, the dielectric of the waveguide can be reliably fixed and the waveguide can be made compact, which improves the element arrangement of the phased array antenna.
can be made to

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of the present invention, FIG. 2 is a diagram showing the configuration of an embodiment of the present invention, FIG. 3 is a diagram showing the detailed structure of an embodiment of the present invention, and FIG. FIG. 5 is a diagram showing the structure of a rectangular ridge waveguide, FIG. 6 is a structural diagram of an example of a double ridge horn antenna, and FIG. 7 is a diagram showing a detailed structure of another embodiment of the invention. Figure 8 is a structural diagram of another example of an antenna that uses a thin film and dielectric material in the opening of a beam-shaped waveguide. Figure 9 is a diagram showing the configuration of a phased array antenna. . In the figure, 10a is a rectangular ridge waveguide, 10b is a circular ridge waveguide, 11a is a first dielectric A, 11b is a first dielectric B, 12 is a second dielectric, 13 is a third dielectric, 16 is the opening, (c+ No. 1212) Neto 46g8/1-F
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Claims (2)

[Claims] (1) In an antenna element using a plurality of rectangular ridge waveguides (10a), a first dielectric material A (11a) and a second dielectric material Three types of dielectrics are arranged in the order of a dielectric (12) and a third dielectric (13), and the third dielectric (13) is provided in close contact with the opening (16), and The first dielectric A (11a) has high-frequency matching characteristics, the second dielectric (12) in the middle has low-frequency matching characteristics, and the third dielectric (11a) in close contact with the opening (16) surface 13) A small antenna spatial matching system characterized in that it has low-range and middle-range matching characteristics and can perform impedance matching over a wide band of one octave or more between the rectangular ridge waveguide (10a) and free space. (2) The rectangular ridge waveguide (1
A small antenna spatial matching system characterized in that 0a) is a circular ridge waveguide (10b).