JPS6218971Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a microwave resonant circuit device used in a microwave band signal receiver, etc., and particularly relates to a stripline formed on a dielectric substrate and a circuit provided near the stripline. The resonant frequency of the resonant circuit formed by the coupling with the dielectric resonator is made so that it does not fluctuate due to temperature changes, etc., and the positional relationship of this coupling can be set accurately. The present invention relates to a resonant circuit device.

An example of a microwave resonant circuit that resonates with a signal having a frequency in the microwave band is a microwave oscillation circuit.
A structure using a three-terminal active element such as a FET (FET) has been proposed. This circuit is shown in FIG.

In FIG. 1, reference numeral 1 denotes a GaAs FET, whose gate electrode G is connected to a stripline 2, and one end of the stripline 2 is grounded via a resistor 3. The source electrode S is connected to a stripline 4, one end of which is grounded via an inductance 5 for high frequency blocking and a bias resistor 6, and the drain electrode D is connected to the stripline 4. 7, and this stripline 7 is connected to the power supply +B via an inductance 8 for high frequency blocking, and one end thereof is connected to the stripline 10 via a gap capacitor 9 for DC blocking. ing. High frequency output terminal OUT from stripline 10
has been derived.

In addition, in order to stabilize the oscillation frequency, a high Q dielectric resonator 11 is installed near the stripline 2.
are provided and connected.

The oscillation circuit configured as above is made of GaAs.
An equivalent impedance element formed by the stripline 2 and the dielectric resonator 11, an equivalent impedance element formed by the stripline 4, and the stripline are connected to each of the gate electrode G, source electrode S, and drain electrode D of the FET 1. 7
Equivalent impedance elements formed by 10 and 10 and gap capacitor 9 are connected to each other, and one ends of these three types of equivalent impedance elements are commonly connected to form a feedback path.
As a result, an oscillation operation is performed, and the oscillation frequency is determined by appropriately selecting the lengths of the striplines 2, 4, and 7, and by setting the position of the dielectric resonator 11 with respect to the stripline 2. Determined by

In an oscillation circuit having such a basic configuration, the dielectric resonator 11 is used to prevent the oscillation frequency from changing due to changes in temperature or changes in the load to which the oscillation output is supplied. In addition, the distances d and 1 of the dielectric resonator 11 to the stripline 2 are adjusted. That is, the temperature characteristics of the oscillation circuit as a whole and the temperature characteristics of the dielectric resonator 11 (characteristics of frequency changes with respect to temperature changes) are determined by the temperature characteristics of the oscillation section including _{the GaAs}・FET 1 and the temperature of the dielectric resonator 11. Therefore, in order to make the overall temperature characteristics excellent, a dielectric resonator 11 with temperature characteristics that cancels out the temperature characteristics of the oscillation section is selected, and this is properly controlled. It is used by placing it in a certain position.

In this case, in order to adjust the resonant frequency of the dielectric resonator 11, as shown in the top sectional view of FIG. 2 and the side sectional view of FIG. Dielectric substrate 1 on the bottom surface
An adjustment plate 16 made of a metal conductor is fixed to an adjustment screw 17 above the dielectric resonator 11 provided together with the stripline 2 on the upper surface of the metal cover 15. The adjustment screw 17 is fixed to the cover 15 by tightening the lock nut 18 after adjusting the screwing amount to obtain the desired characteristics.

However, with such conventional equipment,
Since the ground conductor 13 is uniformly formed on the lower surface of the dielectric substrate 12 facing the dielectric resonator 11, the resonant frequency will change if the thickness of the dielectric substrate 12 changes due to temperature changes. The problem is that it changes drastically. This is because when the dielectric resonator 11 is caused to resonate, most of the electric field distribution at that time is concentrated inside the dielectric resonator 11.
However, if the distance to the ground conductor 13 located very close to the outside of the dielectric resonator 11 changes due to changes in the thickness of the dielectric substrate 12 due to temperature changes, This is due to the fact that the proportion contributing to resonance frequency fluctuation increases. For this reason, when selecting the material for the dielectric substrate, priority is given to the condition that there is little variation in thickness and variation in dielectric constant due to temperature changes, and alumina or ceramic substrates are usually used. The board is not suitable for mass production,
The problem is that it is expensive.

Further, the dielectric resonator 11 is placed on the upper surface side of the dielectric substrate 12, and its position, that is, the distance d and 1 of the dielectric resonator 11 with respect to the stripline 2 is adjusted to obtain predetermined characteristics. After this is obtained, it is fixed to the dielectric substrate 12 using an adhesive. For this reason, there is a problem in that the positional relationship between the dielectric resonator 11 and the stripline 2 is easily disturbed due to vibrations during adjustment work, making it difficult to perform the adjustment work. There is also the problem that this adhesive has an adverse effect, such as a reduction in the Q of resonance, since it is attached at a position close to the .

The present invention was developed in view of the various problems mentioned above, and the purpose of the present invention is to prevent the thickness of the dielectric substrate from changing due to changes in temperature, etc.
In addition to minimizing the variation in resonance frequency caused by this thickness variation, the positional relationship between the dielectric resonator and the stripline can be set accurately, and
An object of the present invention is to provide a microwave resonant circuit device that can be easily operated.

Next, an embodiment of the present invention will be described with reference to FIG. 4 and subsequent drawings. FIG. 4 is a side sectional view of one embodiment of the present invention. In the figure, a stripline 21 is formed on the upper surface of a dielectric substrate 20, and a through hole 20A is provided at a predetermined position near the stripline 21, and a dielectric resonator 22 is provided inside this hole 20A. The lower step is attached. A ground conductor 23 is provided on the lower surface of this dielectric substrate 20.
This ground conductor 23 is formed with a cutout portion 23A having a shape that surrounds the through hole 20A. Furthermore, the dielectric resonator 22 is fixed to the dielectric substrate 20 using an adhesive 24.

The dielectric substrate 20 is housed in a metal chassis 25, and a protrusion 26 formed by pressing or the like is formed on the lower surface of the chassis 25 at a portion opposite to the cutout 23A. The protruding portion 26 covers the missing portion 23A. Further, the upper part of the chassis 25 is open, and a metal cover 27 is provided to cover this opening.
However, it is designed to be fixed with a mounting screw or the like (not shown). This cover 27 is formed with a female threaded portion 27', and an adjustment screw 29 to which an adjustment plate 28 is fixed is screwed into this female threaded portion 27'.
The distance between the adjusting plate 28 and the upper surface of the dielectric resonator 22 can be adjusted. Note that 30 is a lock nut for locking the adjustment screw 29.

Here, when the dielectric resonator 22 is caused to resonate,
At that time, the electric field distribution is mostly in the dielectric resonator 22.
It concentrates inside the dielectric resonator 22, and decays exponentially outside the dielectric resonator 22. In this example,
The upper and lower conductor parts that contribute to setting the resonant frequency are formed by the adjustment plate 28 provided above and the inner wall surface of the protrusion 26 provided below, both of which are connected to dielectric resonance. Since the dielectric resonator 22 is located at a relatively distant position on the outside of the resonator 22, even if the distance between the dielectric resonator 22 and the adjustment plate 28 or the inner wall surface of the protrusion 26 changes somewhat due to temperature changes, the dielectric resonator 22 The effect on resonance frequency fluctuation is extremely small.

Therefore, even if the thickness of the dielectric substrate 20 changes due to temperature fluctuations or the like, this thickness fluctuation does not cause a substantial fluctuation in the resonant frequency.

On the other hand, the stripline 2 of the dielectric resonator 22
1, the dielectric resonator 22 is located in the through hole 20A provided in the dielectric substrate 20.
Since the position is accurately regulated by , the position setting work becomes extremely easy. Furthermore, a dielectric resonator 22
is supported by being bonded and fixed to the lower surface of the dielectric substrate 20 with an adhesive 24, so even if the dielectric substrate 20 undergoes thickness variations due to temperature changes, dielectric resonance due to this thickness variation will be avoided. Vessel 2
There is also the advantage that the positional fluctuation of No. 2 is less likely to occur, and the fluctuation of the resonance frequency is reduced.

Other examples of the fixed state of the dielectric resonator 22 and the dielectric substrate 20 described above are shown in FIGS. 5 to 7.
FIG. 5 shows a through hole 20 formed in a dielectric substrate 20.
The dielectric resonator 22 inserted into A is formed into a truncated cone shape with a smaller diameter at the bottom. 6th
The figure shows the truncated conical shape of the dielectric resonator 22 as shown in FIG. 5 reversed, that is, the diameter is larger at the bottom. In FIG. 7, a flange portion is provided below the dielectric resonator 22, and the flange portion and the lower surface of the dielectric substrate 20 are brought into close contact with each other. In any of these cases, the dielectric resonator 22 is bonded to the lower surface of the dielectric substrate 20 with an adhesive 24.

As is clear from the above description of the embodiments, the microwave resonant circuit device according to the present invention includes a dielectric substrate having a ground conductor formed on one side and a strip line formed on the other side, and this dielectric substrate. a dielectric resonator inserted and supported in a through hole provided so as to pass through the ground conductor; and a conductor that covers a missing portion formed in a portion of the ground conductor corresponding to the through hole. Therefore, even if the thickness of the dielectric substrate fluctuates due to temperature changes or the like, the influence of this thickness fluctuation on the resonant frequency fluctuation can be extremely reduced. In addition, the material of the dielectric substrate
Even if thickness fluctuations and dielectric constant fluctuations due to temperature changes are relatively large, it is possible to use a Teflon substrate, etc., which has good workability and is relatively inexpensive, so there is an advantage that costs can be reduced.

It should be noted that the present invention is not limited to the various embodiments described above, and it goes without saying that various modifications may be made without departing from the gist thereof.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a microwave oscillation circuit, FIG. 2 is a top sectional view showing an example of a conventional microwave resonant circuit device, and FIG. 3 is a side sectional view of the example shown in FIG. FIG. 4 is a side cross-sectional view showing one embodiment of the present invention, and FIGS. 5 to 7 show the fixed state of the dielectric resonator and dielectric substrate in the present invention, respectively.
5 is a cross-sectional view showing an example different from that shown in FIG. 4. FIG. In the figure, 20... dielectric substrate, 20A... through hole, 21... stripline, 22... dielectric resonator, 23... ground conductor, 23A... missing part,
24... adhesive, 25... chassis, 26... protrusion, 27... cover.

Claims (1)

[Scope of utility model registration request] A dielectric substrate having a ground conductor formed on one side and a strip line formed on the other side, and a through hole provided in the vicinity of the strip line; a dielectric resonator fixed to the dielectric substrate on one side with an adhesive; and a dielectric resonator connected to the ground conductor, provided at a position corresponding to the through hole, and formed at the position of the through hole in the ground conductor. a conductor provided with a protrusion covering a missing portion of the conductor, the inner wall surface of the protrusion of the conductor being located at a position relatively distant from an end surface on one surface side of the dielectric substrate of the dielectric resonator. A microwave resonant circuit device that was supposed to be destroyed.