JP3899187B2 - Non-radioactive dielectric guide circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nonradiative dielectric guide circuit with a built-in oscillators.
[0002]
[Prior art]
The non-radiative dielectric guide circuit (NRD guide circuit: Non Radiative Dielectic Wave Guide) has a lower propagation loss than a microwave strip line and is easier to produce a propagation path than a waveguide. In particular, it is attracting attention as a transmission line in the millimeter wave band of 30 GHz or more.
[0003]
This NRD guide circuit has a structure in which a dielectric strip line through which electromagnetic waves propagate is sandwiched between two parallel flat plates of metal, and the facing distance between the parallel flat plates is set to 1/2 or less of the operating frequency wavelength. In other places than the dielectric strip line, the electromagnetic wave is blocked and the radiation thereof is suppressed, so that the electromagnetic wave can be propagated along the dielectric strip line with low loss.
[0004]
On the other hand, although waveguides are difficult to manufacture as described above, they have the advantages of low loss and high reliability, and since there is a lot of know-how accumulated, as a high-frequency transmission line of millimeter waves or more, It has become mainstream.
[0005]
Therefore, there are many cases where it is required to connect the NRD guide circuit and the waveguide, and an NRD guide circuit-waveguide mode converter is required.
[0006]
FIG. 5 is a diagram showing the structure of a conventional NRD guide circuit-waveguide mode converter. Here, the transmission mode of the NRD guide circuit is the currently mainstream LSM ₀₁ mode, and the transmission mode of the waveguide is the TE ₁₀ mode. The NRD guide circuit A has a structure in which a dielectric strip line 3 is sandwiched between two metal parallel plates 1 and 2, and a dielectric strip line 4 having a tapered tip is continuously connected to the dielectric strip line 3. is doing. B is a horn-type waveguide, into which a tapered dielectric strip line 4 is inserted. The LSM ₀₁ mode electromagnetic field distribution is similar to the TE ₁₀ mode electromagnetic field distribution twisted 90 degrees. Therefore, if the parallel plates 1 and 2 and the E-plane of the waveguide B are installed in parallel, the electromagnetic wave is Converts smoothly. When the H plane of the waveguide B and the parallel plates 1 and 2 are parallel, a 90-degree twisted waveguide C is used.
[0007]
In such an NRD guide circuit-waveguide mode converter, as shown in FIG. 6 (a), the magnetic force lines S1 perpendicular to the parallel plates 1 and 2 have the NRD guide circuit A and the horn waveguide B. It can be seen that the electric force lines S2 are parallel to the parallel plates 1 and 2 and the propagation mode is smoothly converted.
[0008]
On the other hand, as a 35 GHz band and 60 GHz band oscillator using an NRD guide circuit, there is a structure combined with a Gunn diode as shown in FIG. In this structure, a mount 6 on which a Gunn diode 5 is mounted together with a dielectric strip line 3 is installed in a space between parallel plates 1 and 2, and a high frequency output oscillated by the Gunn diode 5 passes through a resonator 7. Then, it is led out to the dielectric strip line 3. A bias voltage is applied to the Gunn diode 5 via a choke 8 that blocks high-frequency signal leakage to the power supply system. FIG. 7 (b) is a diagram showing a typical example of the resonator 7, which includes a copper foil portion 7a obtained by patterning a copper foil of a Teflon copper-clad laminated substrate by etching. The oscillation frequency can be adjusted by adjusting the width and length of the copper foil portion 7a.
[0009]
[Problems to be solved by the invention]
However, in the above-described NRD guide circuit-waveguide mode converter, a tapered dielectric strip line 4 continuously extending from the dielectric strip line 3 of the NRD guide circuit A is provided, and this portion is provided. It is coupled to the waveguide B, and there is a problem that the overall shape increases.
[0010]
Further, in an oscillator using an NRD guide circuit, once assembled, there is no means for changing the frequency, and the parallel plates 1 and 2 must be opened again to adjust the resonator 7. When it is desired to oscillate at a specific frequency, it is very difficult to adjust the frequency only by adjusting the copper foil portion 7a of the resonator 7.
[0011]
The present invention has been made in view of the points mentioned above, and its object is as fabricated the waveguide section in the interior of the NRD guide circuit, the oscillator to be able to easily frequency adjustment Is to provide.
[0015]
[Means for Solving the Problems]
The first invention is a non-radiative dielectric in which parallel plates made of two metal plates are arranged at intervals of 1/2 or less of the wavelength of the used frequency band, and a dielectric strip line is sandwiched between the parallel plates. In the body guide circuit, a through hole is formed perpendicular to one of the parallel plates, the inside is closed by the dielectric strip line, an oscillation element is loaded in the through hole, and the frequency adjustment member is disposed outside the through hole. Closed and configured.
[0016]
According to a second aspect , in the first aspect , the frequency adjusting member is a metal or a dielectric that is inserted into the through hole.
[0017]
According to a third invention, in the first or second invention, the oscillation element is a Gunn diode.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
[ Reference example ]
FIG. 1 is a diagram showing the structure of an NRD guide circuit-waveguide mode converter of a reference example of the present invention. The NRD guide circuit A1 has a structure in which a dielectric strip line 3 is sandwiched between two metal parallel plates 1 and 2 and is the same as the conventional one. In the present embodiment, a through-hole 11 having a waveguide-shaped cross section penetrating perpendicularly to one (lower) flat plate 2 is formed, and the inner side (upper side) of the opening is the bottom surface of the dielectric strip line 3. Closed by. Another waveguide 12 is attached to the opening outside the through hole 11 so as to be continuous.
[0019]
Therefore, in this mode converter, the TE ₁₀ mode electromagnetic wave propagating through the waveguide 12 reaches the dielectric stripline 3 through the through hole 11 in the same TE ₁₀ mode, and here, the LS M of the NRD guide circuit A1. _It is converted into ₀₁ mode and propagates through the dielectric stripline 3.
[0020]
FIG. 2 is a diagram showing a state of change of electromagnetic waves from the waveguide 11 to the dielectric strip line 3. 2A is a cross-sectional view taken along the line aa in FIG. 1 and shows the state of the magnetic force lines S1, and FIG. 2B is a cross-sectional view taken along the line bb in FIG. Show. The magnetic field lines S1 are parallel to the H surface of the waveguide 12 for the NRD guide circuit A1, the through hole 11, and the waveguide 12, and the electric field lines S2 are all parallel to the parallel plates 1 and 2. Therefore, the electromagnetic wave can smoothly shift the propagation mode from the waveguide 12 to the dielectric strip line 3.
[0021]
For impedance matching between the NRD guide circuit A1 and the through-hole 11, one end of the dielectric strip line 3 is opened (shorter than the parallel plates 1 and 2), and the waveguide hole 11 extends from that end. It intends line by adjusting the distance to the formation position L (of (a) see FIG. 2).
[0022]
[ Example ]
FIG. 3 is a diagram showing the configuration of the oscillator according to the embodiment of the present invention . Here, the Gunn diode 21 is loaded in the through hole 11 described above. 4A is a cross-sectional view taken along the line aa in FIG. 3, and FIG. 4B is a cross-sectional view taken along the line bb in FIG. 3, specifically showing the portion. The Gunn diode 21 is positioned in the through hole 11 while being sandwiched between the pedestal 22 and the pressing seat 23, and a bias voltage is applied from the bias post 24 through the pressing seat 23. Reference numeral 25 denotes a metal plate (or dielectric plate) whose insertion amount can be adjusted into the through hole 11. Reference numeral 26 denotes a modulation printed board on which a beam lead type PIN diode 27 is mounted, and is sandwiched between the dielectric strip line 3 so that the PIN diode 27 is positioned in the middle of the dielectric strip line 3. As shown in FIG. 4C, a modulated signal is applied to the PIN diode 27 of the printed circuit board 26 via a choke 28 for blocking a high-frequency signal.
[0023]
In this embodiment, since a cavity resonator is formed in the through hole 11, oscillation is started by applying a bias to the Gunn diode 21, and an electromagnetic wave generated therein is transmitted from the through hole 11 to the dielectric strip line 3. After reaching the bottom surface and converted to the NRD line propagation mode LSM ₀₁ here, it propagates through the dielectric strip line 3 and reaches the PIN diode 27. Therefore, if this PIN diode 27 is controlled to be turned on / off by a pulse signal, an electromagnetic wave is transmitted through or reflected at this portion, so that a pulse-modulated electromagnetic wave can be obtained at the end of the dielectric strip line 3. It becomes like this.
[0024]
In the above, the adjustment of the oscillation frequency is performed by adjusting the insertion amount of the metal plate 25 inserted into the through hole 11. The through-hole 11 constitutes a cavity resonator closed by the metal plate 25. By adjusting the amount of insertion of the metal plate 25, the cavity resonance frequency changes and the oscillation frequency changes.
[0025]
【The invention's effect】
As described above, according to the present invention, a waveguide-shaped through hole is formed in the flat plate constituting the nonradiative dielectric guide circuit, and the mode converter of the nonradiative dielectric guide circuit and the waveguide is configured in this portion. Therefore, the mode converter can be realized in a small space. In the oscillator, an oscillation element is loaded into the through hole, and the oscillation frequency is adjusted by adjusting the cavity volume by the frequency adjusting member. Therefore, the frequency can be continuously adjusted even after assembly.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an NRD guide circuit-waveguide mode converter according to a reference example of the present invention.
2A is an explanatory diagram of a magnetic field distribution of the mode converter of FIG. 1, and FIG. 2B is an explanatory diagram of an electric field distribution.
3 is a diagram showing a schematic configuration of a NRD guide circuit oscillator according to the embodiment of the present invention.
4A is a cross-sectional view taken along line aa in FIG. 3, FIG. 4B is a cross-sectional view taken along line bb in FIG. 3, and FIG. 4C is a plan view of a modulation printed board.
FIG. 5 is a diagram showing a schematic configuration of a conventional NRD guide circuit-waveguide mode converter;
6A is an explanatory diagram of the magnetic field distribution of FIG. 5, and FIG. 6B is an explanatory diagram of the electric field distribution.
FIG. 7 is a diagram showing a schematic configuration of a conventional NRD guide circuit oscillator.
[Explanation of symbols]
1, 2: parallel plate of metal, 3, 4: dielectric strip line, 5: Gunn diode, 6: mount, 7: resonator, 8: choke
11: Through hole, 12: Waveguide,
21: Gunn diode, 22: Pedestal, 23: Seat, 24: Bias post, 25: Metal plate, 26: Printed circuit board for modulation, 27: PIN diode, 28: Choke.

Claims (3)

In a non-radiative dielectric guide circuit in which parallel plates made of two metal plates are arranged at intervals of 1/2 or less of the wavelength of the used frequency band, and a dielectric strip line is sandwiched between the parallel plates,
Perpendicular to one of said parallel plates, a through hole is formed inside that closed in the dielectric strip line,
An oscillation element was loaded in the through hole, and the outside of the through hole was closed with a frequency adjusting member .
A non-radiative dielectric guide circuit. The non-radiative dielectric guide circuit according to claim 1, wherein the frequency adjusting member is a metal or a dielectric inserted into the through hole . The non-radiative dielectric guide circuit according to claim 1, wherein the oscillation element is a Gunn diode .

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