JPS6161502A - Dielectric resonator - Google Patents

Abstract

PURPOSE:To suppress the frequency fluctuation of an oscillator due to temperature change by combining two kinds of metallic members having different thermal expansion coefficient and utilizing the difference in length due to expansion. CONSTITUTION:The thermal expansion coefficient for a screw 3 and a metallic piece 7 is different from each other, the thermal expansion coefficients are taken as (b), (a), the distance is taken as (l) and the length of the screw 3 is taken as l1, and the temperature range is DELTAl of the distance 5 due to tempera ture change DELTAT is expressed as DELTAll=DELTAT.[al-l1(b-a)]. The size has a relation with an oscillator frequency and when the range in DELTAl changes, the temperature fluctuation width of the oscillated frequency is changed. When b>a in the relation with DELTAl, the value DELTAl changes when the (l) is changed and the polarity of the DELTAl is changed at a certain (l). Since the (l) must be larger than 0, when a more negative is required, the two metals having a large thermal expansion coefficient difference is used.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a converter for a satellite broadcast direct receiving device, etc.;
This relates to the dielectric resonator used, and especially to the stabilization of its frequency against changes in humidity.

[Conventional technology]

Generally, the performance required for this type of resonator (oscillator) is that the oscillation frequency is 10.678 GHz, and the oscillation frequency fluctuation in the temperature range (-30°C to +50°0) is ±1.5. A very narrow fluctuation range, such as MHz or less, is required. Figure 1 shows a cross-sectional side view of a conventional device of this type. (21 is a metal plate for fine adjustment of the oscillation frequency, (3) is a metal plate (screw part for raising and lowering 21, (4) is a case, (51 is a dielectric body) The opposing distance between (1) and metal plate (2), (
61 is the length of the threaded portion (3) inside the case.

Next, the operation of the prior art will be explained.

By moving the screw part (3), the interval (5) can be changed,
Set the oscillation frequency of the oscillator. After setting the desired oscillation frequency at room temperature, fix the screw (3) to the case +41 and apply C2 so that it does not move.In this conventional type, the screw part (3) and the case (4) are made of the same material or have a coefficient of expansion that does not change much, so when the temperature changes, the interval (5) will change due to the thermal expansion of the case (4).
changes. Furthermore, fluctuations in the frequency range specific to the oscillator occur. Conventionally, a dielectric material (11) having a temperature coefficient that corrects the oscillation frequency fluctuation has been used to suppress the temperature fluctuation of the oscillation frequency.

Conventional devices are configured as shown above (;
When the temperature changes, the oscillation frequency changes, and frequency fluctuations occur due to variations in active elements and variations inherent in the oscillator, so the temperature fluctuations in the oscillation frequency become large and the required performance is no longer satisfied. In that case, it is necessary to change to a dielectric resonator with a different temperature coefficient, but due to variations in the dimensions and temperature coefficient of the changed dielectric resonator, readjustment is necessary. There were drawbacks such as poor reproducibility and a considerable amount of time required for adjustment.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional products as described above, and by combining two types of metal members with different coefficients of thermal expansion and utilizing the difference in their expansion lengths, temperature changes can be reduced. The present invention provides a dielectric resonator capable of suppressing frequency fluctuations of an oscillator relative to the oscillator.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 2, (1) is a dielectric resonator, (2) is a metal plate for fine adjustment of the oscillation frequency, (3) is a screw part for raising and lowering the metal plate (2), and (4) is a case. , (5) is the distance between the dielectric resonator (1) and the metal plate (2), (6) is the screw,
The length of part (3) inside the case, (7) is a metal piece with a different coefficient of expansion from the threaded part (3), and this metal piece (7) is attached to the case (4) so that it can be moved up and down from its mounting screw +81 +-. ). +91 is the sum of the distance (5) and the length of the threaded portion (61).

Figure 2 (-) Use threaded part (3) and metal piece (7) with clearly different coefficients of thermal expansion, each coefficient of expansion is a, the interval (5) is!, screw When the length of part (3) is 11 and the temperature range is n, the change Δ in interval (5) due to temperature change in ΔT is Δj=ΔT ・(
aj −is (k>−a) ) ・−・−・−・Set (1) is obtained. There is a relationship between Δ and the oscillator frequency, and as the range of aj changes, the temperature fluctuation range of the oscillation frequency also changes.An example of this is shown in FIG.

By the way, in the case of b) a, the relationship between aj and ) is as shown in FIG.
When it becomes, the sign of Δ) changes. However, since ∆ must be greater than 0, when ∆ requires a large negative value (= should be used with a large difference in the expansion coefficients of the two metals).

Next (:, An example of adjusting the frequency will be explained.

When the oscillation frequency of the oscillator has a temperature fluctuation range of 1Δf due to the active elements and the oscillator, Δ] corresponding to +Δf to cancel it is determined from Figure 3, and l corresponding to 2ΔJC is determined from Figure 4. ,! 11, which corresponds to
Loosen the metal piece (7) and set the length of the metal piece (7) to 11.
ga l l”l.

After adjusting the threaded part (3) so that By changing 11 in this way, it is possible to easily set the desired temperature fluctuation range. Furthermore, the temperature fluctuation range can be made close to O, and the required performance can be fully satisfied even if there are variations in active elements and variations inherent in the oscillator.

Although the length of the metal piece (7) was adjusted in the above embodiment, it is also possible to provide a fixator αq as shown in FIG.
The same effect can be obtained by changing the length (6) of 3). In this case, case (4) is the metal piece (7) of the above example.
Same as:: A coefficient of thermal expansion that is different from that of the threaded portion (3) shall be used.

〔Effect of the invention〕

As described above (-1) According to this invention (=), since the threaded part and the metal piece are configured to have different coefficients of thermal expansion and the length of the metal piece can be adjusted, only the variation in the facing distance between the dielectric material and the metal plate is possible. Rather, even if there are active elements or other frequency fluctuation factors due to temperature, it is possible to stabilize the frequency including that.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view showing a conventional dielectric resonator (oscillator), FIG. 2 is a cross-sectional side view of a dielectric resonator (oscillator) according to an embodiment of the present invention, and FIGS. The figure is a characteristic diagram for explaining the operation of Fig. 2, and Fig. 5 is a cross-sectional side view showing another embodiment of the present invention. (I+... dielectric resonator, (2)... Metal plate, (3
)...Threaded part, (4)...Case, (7)...Metal piece, (8)...Mounting screw. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] A dielectric provided in the case, a metal plate disposed opposite to the dielectric, this metal plate provided on one end side,
An adjusting member for adjusting the facing distance between the dielectric and the metal plate, supporting the other end of the adjusting member so as to be movably adjustable, forming a part of the case parallel to the adjusting member, and extending the length of the adjusting member. A dielectric resonator comprising a metal piece attached to the case so that the height can be adjusted, and the metal piece and the adjustment member have different coefficients of thermal expansion.