JP3304483B2 - Leak wave NRD guide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leaky wave NRD guide capable of canceling a reflected wave generated from a discontinuous element provided on a dielectric strip.

[0002]

2. Description of the Related Art NRD guides (Non-radiative dielectric lines, non-radiative dielectric lines) are used as new dielectric lines for millimeter-wave integrated circuits.
ielectric Waveguide) is known. This NRD guide has a structure in which a dielectric strip is sandwiched between upper and lower metal plates. Then, a discontinuous element such as a concave portion is provided on the dielectric strip, and by exciting the dielectric strip, a radio wave is generated between the upper and lower metals.

[0003]

Conventionally, a dielectric strip is provided with a concave portion for each radio wave propagation wavelength λg, and a leaky wave NRD guide is used as a discontinuous element.

However, since reflected waves generated from the concave portions of the dielectric strip are added, the input impedance is deteriorated, and the band is narrowed by the local matching method.
Further, the reflected wave due to the concave portion of the dielectric strip increases with the number of concave portions, so that as the number of concave portions increases, the input impedance further deteriorates.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to cancel out reflected waves generated from discontinuous elements provided on a dielectric strip to thereby reduce input impedance.
Leaky wave NRD that can prevent dance deterioration and widen the band
To provide a guide.

[0006]

Means for Solving the Problems] leaky wave NRD guide according to claim 1, electrostatic the NRD guide of the dielectric strip
A first discontinuous element for emitting a wave is provided, and the first discontinuous element is located at a distance of λg / 4 from the first discontinuous element.
And a second discontinuous element for canceling the reflected wave of the radio wave reflected in the above .

[0007] The leaky wave NRD guide according to claim 2 is:
Radio waves are emitted to the dielectric strip of the NRD guide every λg
A recess is provided as a first discontinuous element for causing the first discontinuous element to be located at a distance of λg / 4 from the first discontinuous element.
A concave portion serving as a second discontinuous element for canceling the reflected wave of the radio wave reflected by the mobile terminal .

[0008] The leaky wave NRD guide according to claim 3 is:
A first discontinuous element is provided for each λg on the upper and lower sides of the dielectric strip, and a first discontinuous element provided on the lower side of the dielectric strip is provided on the upper side of the dielectric strip. It is provided at a position shifted by λg / 2 from the first discontinuous element, and vertically symmetrically at a distance of λg / 4 from the first discontinuous element provided above and below the dielectric strip. A concave portion is provided as a second discontinuous element.

According to a fourth aspect of the present invention, there is provided a leaky wave NRD guide.
A concave portion as a first discontinuous element is provided for each of λg on the upper side and the lower side of the dielectric strip, and the first discontinuous element provided on the lower side of the dielectric strip is provided on the upper side of the dielectric strip. Λg / 2 from the first discontinuous element provided
A concave portion as a second discontinuous element is vertically symmetrically provided at a position shifted by λg / 4 from the upper and lower first discontinuous elements.

[0010]

The leaky wave NRD according to any one of claims 1 to 4
Also in the guide, the second discontinuous element is provided on the dielectric strip at a distance of λg / 4 from the first discontinuous element. The generated reflected waves are canceled out.
For this reason, it is possible to prevent the input impedance from deteriorating and to provide a leaky wave NRD guide capable of widening the band.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a basic NRD guide,
FIG. 2 is a perspective view of the leaky wave NRD guide according to the first embodiment of the present invention, in which upper and lower metal plates are removed, FIG. 3 is a characteristic diagram when a pair of second discontinuous elements is provided, and FIG. FIG. 4 is a frequency characteristic diagram of a reflection coefficient when a continuous element is paired.

First, the configuration of a basic NRD guide will be described with reference to FIG. A waveguide using a dielectric such as an NRD guide is advantageous in reducing a conductor loss due to a metal wall in a microwave or millimeter wave band.

As shown in FIG. 1, the NRD guide has a structure in which a dielectric strip 13 is sandwiched between parallel metal plates 11 and 12. The dimensions of the dielectric strip 13 are the height a. Those having a width b and the size of Equations 1 and 2 are used (λ
Is the free space wavelength, ε _r is the relative permittivity of the dielectric strip), and the material is a high-frequency low-loss material such as Teflon, polyethylene, or polystyrene.

[0014]

(Equation 1)

[0015]

(Equation 2)

In general, the line does not radiate in the transmission mode (hybrid mode) of the homogeneous NRD guide. However, in the present invention, a discontinuous element is provided on the dielectric strip to radiate radio waves between the parallel metal plates, and the antenna or the coupling line This is an invention relating to matching when a leaky wave NRD guide to be used is configured. Hereinafter, the contents will be described in detail.

FIG. 2 is a perspective view of the leakage wave NRD guide with the upper and lower metal plates 11 and 12 removed. As shown in FIG. 2, a first discontinuous element 14 is provided on the dielectric strip 13 for each λg, and second discontinuous elements 15 and 16 are provided vertically and symmetrically at a distance of λg / 4 therefrom. . First and second
In general, the discontinuous elements 14, 15, and 16 have a cutout in the dielectric strip 13 at every λg. FIG. 2 shows only one block for the sake of simplicity.

As described above, λg
By providing second discontinuous elements 15 and 16 having concave shapes with cuts in the upper and lower portions at / 4, the first discontinuous element 14 functions as an element that emits radio waves,
The matching function for canceling the reflected wave from the first discontinuous element 14 can be exhibited by the second discontinuous elements 15 and 16.

That is, if the reflection coefficient from the first discontinuous element 14 and the reflection coefficient from the second discontinuous elements 15 and 16 have the same amplitude and the same phase, the interval between each discontinuous element is set to λg
/ 4 makes it possible to cancel out reflected waves,
A return loss can be made to the leaky wave NRD guide.

These effects have been confirmed by experiments and will be described below. The frequency used in this experiment was 24 GH
In the z band, the height of the dielectric strip 13 is a = 5.9 mm,
A Teflon rod having a width b = 5.4 mm was used. First
Of the concave portion of the discontinuous element 14 is d = 2.5 mm, w =
The power reflection coefficient A was 4.2% and the reflection phase φ was 0.37 when 2.5 mm was one. Here, the reflection phase φ is set to φ = 1 / λg when the distance from the concave portion to the position of the valley position of the standing wave generated by the traveling wave and the reflected wave from the concave portion is 1.

FIG. 3 shows that the second discontinuous elements 15 and 16
In the case of the pair, the measured values of the reflection coefficient A and the reflection phase φ when the width w of the concave portion is changed, assuming that the depth d of the concave portion of the second discontinuous elements 15 and 16 are 2 mm, are shown. The reflection coefficient A is almost zero when the width w = 0, and as the width w increases, the reflection coefficient A increases. First discontinuous element 14 and second discontinuous element 1
The reflection system numbers A of 5 and 16 have the same reflection coefficient at w = 2 mm. At that time, the reflection coefficient A = 4.4% and the reflection phase φ =
0.48.

FIG. 4 shows the frequency characteristics of the dielectric strip 13 under the conditions of FIG. As shown in FIG. 4, the reflection coefficient A was 24% and was 4.4% when only the first discontinuous element 14 was used.
Is provided, the reflection coefficient A becomes almost zero, and the frequency characteristics of the dielectric strip 13 are excellent in a wide band.

FIG. 5 is a sectional view of a dielectric strip according to a second embodiment of the present invention, showing the structure of the discontinuous element of the dielectric strip 13 with the upper and lower metal plates 11, 12 of the NRD guide removed. Things. In the figure, Rn is a first discontinuous element, and _Mn1 and _Mn2 are second discontinuous elements.
That is, a concave portion Rn (n is an odd number) is provided for each λg on the upper side of the dielectric strip 13 of the NRD guide, and a concave portion Rn (n is an even number) is provided on the lower side shifted by λg / 2 therefrom. Λg / 4 from each first discontinuous element
The recesses M _n1 and M _n2 are provided as second discontinuous elements symmetrically up and down only at a distance.

FIG. 6 shows the frequency characteristics of the reflection coefficient when 16 first discontinuous elements are provided. Frequency is 23-2
5 GHz, the dotted line in the graph indicates the reflection coefficient with respect to the frequency when only the first discontinuous element is provided, and the solid line indicates the reflection coefficient with respect to the frequency when the second discontinuous element is provided.

As is clear from the figure, the reflection coefficient A was 95% at 24 GHz, but by providing the second discontinuous element, the reflection coefficient A could be reduced to 1% or less, and a good result was obtained. Could be obtained.

Referring to FIG. 7, an overall view of a leaky wave NRD guide using the dielectric strip shown in FIG. 5 will be described.
In FIG. 7, a dielectric strip 23 is sandwiched between an upper metal plate 21 and a lower metal plate 22, and the dielectric strip 23 is excited by a coaxial line 24.

Since no standing wave is generated in the dielectric strip 23, matching with the coaxial line 24 can be easily performed. First discontinuous elements Rn-1, Rn, Rn + 1
.. Are shifted by λg / 2 as shown in FIG.
Since the point wave sources are arranged at an interval of 1/2, the radio wave is radiated in the θ = 90 ° direction with the vertical polarization, and the directivity is xz
The surface is sharp. On the other hand, λ
When the first discontinuous elements Rn are provided at intervals shorter than g, the directivity of the radio wave bends in the direction of θ <90 °.

Next, a planar antenna using a leaky wave NRD guide according to the present invention will be described with reference to FIG. As shown in FIG. 8, a dielectric strip 33 is sandwiched between two upper and lower metal plates 31 and 32, and the dielectric strip 33 is excited by a coaxial line 34. The periphery of the upper and lower two metal plates 31 and 32 is short-circuited by a metal wall 35. The upper metal plate 31 is provided with a slot 36 for each wavelength, and the end of the dielectric strip 33 is open.

With the above-described configuration, the leaky wave radiated from the dielectric strip 33 travels toward the broadside, propagates in the lower space of the row of slots 36, and is reflected by the metal wall 35 at the right end. A standing wave distribution is formed between the metal plates 31 and 32.

Each slot 36 of the upper metal plate 31
Since the magnetic field is at the maximum position at one wavelength interval of the standing wave, each slot 36 is excited in phase,
Are also in phase in the longitudinal direction, so that linearly polarized waves are radiated in the direction perpendicular to the antenna plane. Next, a dielectric strip according to a third embodiment of the present invention will be described with reference to FIG.

FIG. 9 is a perspective view showing only the dielectric strip 43, and the upper and lower metal plates are not shown. As shown in FIG. 9, the dielectric strip 43 is provided with a projection,
The convex portions 45, 4 as the second discontinuous elements are vertically symmetrically separated from the convex portion 44 as the first discontinuous element by λg / 4.
6 is provided. As described above, even when the projections are provided as the discontinuous elements on the dielectric strip 43, the same effects as when the recesses are provided as the discontinuous elements as shown in FIG. 2 are obtained.

Next, a dielectric strip according to a fourth embodiment of the present invention will be described with reference to FIG. FIG.
10A is a sectional view of the dielectric strip 53, and FIG.
FIG. 11 is a sectional view taken along line AA of FIG. As shown in FIG. 10, a convex portion is formed on the upper metal plate 51 and the lower metal plate 52 by pressing or the like, and the convex portion 5 as a first discontinuous element is formed.
The convex portions 55 and 56 as second discontinuous elements are provided symmetrically in the vertical direction at a distance of λg / 4 from
Are sandwiched.

With this configuration, the discontinuous elements can be provided on the upper and lower metal plates 51 and 52 without providing the discontinuous elements on the dielectric strip and 53, as shown in FIG. This has the same effect as the case where a concave portion is provided in the dielectric strip 13 as an element.

Next, a dielectric strip according to a fifth embodiment of the present invention will be described with reference to FIG. FIG.
11A is a sectional view of a dielectric strip, and FIG. 11B is a sectional view taken along line BB of FIG. 11A. As shown in FIG. 11, a concave portion is formed inside the upper metal plate 61 and the lower metal plate 62, and the second concave portion is vertically symmetrically spaced from the concave portion 64 as the first discontinuous element by λg / 4. In this embodiment, concave portions 65 and 66 as continuous elements are provided, and a dielectric strip 63 is inserted.

With this configuration, even if the upper and lower metal plates 61 and 62 are not provided with discontinuous elements, the upper and lower metal plates 61 and 62 are provided with recesses as discontinuous elements, as shown in FIG. This has the same effect as the case where a concave portion is provided in the dielectric strip 13 as a discontinuous element.

As described above, in any of the above-described embodiments, radio waves are radiated from the first discontinuous element provided on the dielectric strip of the leaky wave NRD guide, and reflected waves generated from the first discontinuous element are reflected. Since the second discontinuous elements cancel each other, the input impedance becomes extremely good.
Further, the leaky wave NRD guide can be operated as a directional coupler or a distributor.

[0037]

As described in detail above, according to the present invention, the reflected wave generated from the discontinuous element provided on the dielectric strip is canceled to prevent the input impedance from deteriorating and to widen the band. A leak wave NRD guide that can be taken can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a basic NRD guide.

FIG. 2 is a perspective view of the leakage wave NRD guide according to the first embodiment of the present invention, from which upper and lower metal plates have been removed;

FIG. 3 is a characteristic diagram when the second discontinuous element is a pair.

FIG. 4 is a frequency characteristic diagram of a reflection coefficient when the second discontinuous element is a pair.

FIG. 5 is a schematic view of an NRD guide according to a second embodiment of the present invention, in which upper and lower metal plates are removed.

FIG. 6 is a frequency characteristic diagram of a reflection coefficient of the NRD guide according to the second embodiment.

FIG. 7 is a perspective view showing the overall configuration of a leaky wave NRD guide.

FIG. 8 is a perspective view showing a planar antenna employing a leaky wave NRD guide according to the present invention.

FIG. 9 is a perspective view of a leaky wave NRD guide according to a third embodiment of the present invention.

FIG. 10 is a cross-sectional view of a leaky wave NRD guide according to a fourth embodiment of the present invention, from which upper and lower metal plates have been removed.

FIG. 11 is a sectional view of a leaky wave NRD guide according to a fifth embodiment of the present invention, from which upper and lower metal plates have been removed.

[Explanation of symbols]

11, 12: metal plate, 13: dielectric strip, 14 ...
First discontinuous elements, 15, 16... Second discontinuous elements.

──────────────────────────────────────────────────続 き Continued on the front page (72) Atsushi Minase, Inventor 1406 Hasunuma, Omiya City, Saitama Prefecture Yagi Antenna Co., Ltd. ) Inventor Toshihiko Agatsuma 4-16-20 Tsurugaoka, Izumi-ku, Sendai, Miyagi Prefecture (56) References West German Patent Application Publication 3418083 (DE, A1) Agatsuma, Yoneyama, Notched NRD Guide Leaky Wave Antenna, IEICE Autumn Meeting Lecture Paper B-70 (58) Fields surveyed (Int. Cl. ⁷ , DB name) H01P 3/16 JICST file (JOIS)

Claims (4)

(57) [Claims] 1. A radio wave is applied to a dielectric strip of an NRD guide.
A first discontinuous element for radiating light, and the first discontinuous element is provided at a position separated by λg / 4 from the first discontinuous element.
Second to cancel the reflected wave of the radio wave reflected in
A leaky wave NRD guide characterized in that a discontinuous element is provided. 2. The method according to claim 1, wherein the dielectric strip of the NRD guide is λg.
A concave portion is provided as a first discontinuous element for emitting a radio wave every time, and a distance of λg / 4 from the first discontinuous element is provided.
A reflected wave of the radio wave reflected by the first discontinuous element
A leak wave NRD guide characterized by providing a concave portion as a second discontinuous element for canceling out . 3. A first discontinuous element is provided for each of λg on the upper side and the lower side of the dielectric strip, and the first discontinuous element provided on the lower side of the dielectric strip is a dielectric strip. Λ from the first discontinuous element provided above
g / 2, and is shifted by λ from the first discontinuous elements provided above and below the dielectric strip.
2. The leaky wave NRD guide according to claim 1, wherein a concave portion as a second discontinuous element is provided symmetrically in a vertical direction at a distance of g / 4. 4. A concave portion as a first discontinuous element is provided for each λg on the upper side and the lower side of the dielectric strip, and the first discontinuous element provided on the lower side of the dielectric strip is It is provided at a position shifted by λg / 2 from the first discontinuous element provided on the upper side of the dielectric strip, and vertically symmetrically at a distance of λg / 4 from the upper and lower first discontinuous elements. 2. The leaky wave NRD guide according to claim 1, wherein a concave portion is provided as a second discontinuous element.