JPH04335701A - Microwave oscillator - Google Patents

Abstract

PURPOSE:To make the entire oscillator small by minimizing the projection from a case. CONSTITUTION:The microwave oscillator is provided with an oscillation circuit comprising combination of a microstrip line 5, an active element and a passive element in the vicinity of a dielectric resonator 4 fixed onto a dielectric board 2 in a case 10 via a support base 3 and with a frequency adjustment means comprising a metal-made disk 8 with a different thickness of a circumference on the dielectric resonator 4, inserted to a throughhole of the case 10 and fixed to a lower end of a metal-made screw 7 threaded to a nut 6 on the throughhole. An upper end of the screw section 7 is not projected from the upper face of the nut 6 when the screw section of the frequency adjustment means is turned.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oscillator using a dielectric resonator.

This type of microwave oscillator is applied as a local oscillator of a wireless device. 2. Description of the Related Art With the recent trend toward miniaturization of communication devices and the like, there is a demand for a microwave oscillator that can further downsize the entire device.

0003

2. Description of the Related Art FIG. 8 is a sectional view showing the structure of a conventional microwave oscillator using a dielectric resonator.

In this figure, reference numeral 10 denotes a box-shaped metal case. Reference numeral 11 denotes a dielectric substrate installed on the bottom surface inside the casing 10.

A microwave oscillation circuit as shown in FIG. 9 is constructed on the upper surface of the dielectric substrate 11. As shown in FIG. In this circuit, reference numeral 12 denotes a cylindrical dielectric resonator made of ceramic material, which is fixed on a dielectric substrate 11 via a support 13.

A main line 14 is a microstrip line, and is arranged near the dielectric resonator 12. Further, one end of the main line 14 is grounded via a terminating resistor 15, and the other end is connected to a base end B of a transistor 16.

A collector end C of the transistor 16 is grounded, and an emitter end E is connected to an open stub 17 formed by a microstrip line. An output extraction stub 18 is formed of a microstrip line near the open stub 17 , and one end of the stub 18 is connected to an output terminal 19 .

Reference numeral 20 shown in FIG. 8 is a metal screw, which is inserted into a through hole formed in the housing 10 and is attached by being screwed onto a nut 21 on the through hole.

In the microwave oscillator having such a configuration, the microwave due to the resonant frequency of the dielectric resonator 12 propagates to the main line 14 and is turned back at the open stub 17, and the microwave is further outputted. It is output from the output terminal 19 via the stub 18.

[0010] In order to set the frequency of the microwave outputted from the output terminal 19 to a desired frequency, the resonant frequency of the dielectric resonator 12 can be changed, and this can be done by turning the screw 20. , the distance between the lower end surface of the screw 20 and the upper surface of the dielectric resonator 12 may be adjusted. The narrower the interval, the higher the frequency.

[0011]

By the way, in the above-mentioned microwave oscillator, when the distance between the lower end surface of the screw 20 and the upper surface of the dielectric resonator 12 is increased in order to lower the frequency, the casing 10 The length of the screw 20 protruding from the microwave oscillator becomes longer, and when the microwave oscillator is incorporated into a communication device, etc., the protrusion of the screw 20 must be taken into consideration, which causes the problem that the entire device must be made larger. was there.

[0012] The present invention has been made in view of the above points, and it is an object of the present invention to provide a microwave oscillator that can reduce the size of the entire device by minimizing the protruding portion from the housing. It is an object.

[0013]

[Means for Solving the Problems] FIG. 1 shows a sectional view for explaining the principle of a microwave oscillator according to the present invention. In the figure,
1 is a metal housing. A dielectric substrate 2 is housed and fixed in this housing 1. A dielectric resonator 4 is fixed on the dielectric substrate 2 via a support 3, and a microstrip line 5 and an active An oscillation circuit is formed by combining the elements and passive elements.

Further, above the dielectric resonator 4, there is a metal thread 7 fixed to the lower end of the metal screw part 7, which is inserted into the through hole of the housing 1 and screwed into the nut 6 on the through hole. Metal disks 8 having different thicknesses along the circumference are arranged.

The disc 8 is adapted to rotate together with the threaded portion 7, and the threaded portion 7 is formed in such a length that its upper end does not protrude from the upper surface of the nut 6 when rotating.

[0016]

[Operation] According to the present invention described above, the disk 8 is rotated by turning the screw portion 7, and the thicker portion of the disk 8 is
When located above the dielectric resonator 4, the distance between the bottom surface of the disk 8 and the top surface of the dielectric resonator 4 becomes narrower, resulting in a higher resonant frequency; when a thinner portion is located, the distance becomes wider, resulting in a higher resonant frequency. becomes lower. In other words, a desired frequency can be obtained by arbitrarily turning and fixing the screw portion 7.

Furthermore, even if the threaded portion 7 is rotated, the threaded portion 7
Since the upper end surface does not protrude from the upper surface of the nut 6, the nut 6 is the only portion that protrudes from the first surface of the casing. Conventionally, the frequency was adjusted by turning a long screw placed above the dielectric resonator and protruding from the housing. If the distance between the screw and the end face was widened, the screw would protrude longer to the outside of the housing.

[0018] In other words, when a conventional microwave oscillator is incorporated into a communication device, etc., the structure must take into consideration the protrusion of the screw, and the overall size of the device must be increased accordingly. In the microwave oscillator of the present invention, since the only protruding part is the nut 6, the overall size of the device can be made smaller than in the conventional case.

[0019]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a sectional view showing the configuration of a microwave oscillator according to a first embodiment of the present invention. In this figure, parts corresponding to those of the conventional example shown in FIG. 8 are given the same reference numerals, and their explanations will be omitted.

The microwave oscillator according to the first embodiment is shown in FIG.
What is different from the conventional microwave oscillator shown in FIG. 8 is that instead of the screw 20 which is the frequency adjustment means shown in FIG.
It is equipped with a frequency adjustment means consisting of a metal disc 31 fixed to the lower end.

The disk 31 has a cylindrical shape with a hollow lower end, and the lower peripheral portion 31a extends from the thickest portion 32 to the arrow 33, as shown in the bottom view of the disk 31 in FIG. It gradually becomes thinner as it goes around in the direction, and the thinnest part 34 is formed in a shape joined to the thickest part 32.

Furthermore, when the peripheral portion 31a of the disk 31 rotates by turning the screw portion 30, the dielectric resonator 1
It is arranged so as to pass above the center of 2.

The threaded portion 30 is formed to a length such that its upper end does not protrude from the upper surface of the nut 21 when the threaded portion 30 is turned.

[0024] When changing the frequency to a desired frequency using such a frequency adjusting means, the screw portion 30 may be turned. This is because the disk 31 rotates by turning the screw portion 30, and this rotation causes the peripheral portion 31a having a different thickness to pass above the center of the dielectric resonator 12, so that the peripheral portion 31a of the disk 31 Bottom surface and dielectric resonator 1
This is because the distance from the top surface of 2 changes, and the frequency changes accordingly.

By the way, in the conventional microwave oscillator, there have been cases where the screw 20 protrudes long from the housing 10 when changing the frequency, but in the microwave oscillator of the first embodiment, the screw part Even if the nut 30 is turned, its upper end will not protrude beyond the upper surface of the nut 21.

In other words, since only the nut 21 protrudes from the housing 10, when this microwave oscillator is incorporated into a communication device or the like, the entire device can be made smaller than before.

Furthermore, as shown in FIG. 4 (cross-sectional view) and FIG. 5 (bottom view), instead of the disk 31, a disk 35 in the shape of a cylinder cut diagonally along a plane may be used to achieve the above-mentioned effect. The frequency can be changed in this way, and the entire device can be made smaller.

Next, a microwave oscillator according to a second embodiment will be explained with reference to FIG. The microwave oscillator shown in FIG. 6 includes a first gear 40 in which teeth of an arbitrary pitch are formed around the disk 31 shown in FIG. It has a frequency adjustment means consisting of.

However, the fine adjustment screw 42 is inserted into a through hole provided in the housing 10 and is screwed onto a nut 43, so that when the fine adjustment screw 42 is turned, the upper end of the fine adjustment screw 42 is inserted into a through hole provided in the housing 10. The length is such that it does not protrude from the top surface. Further, FIG. 7 shows a plan view of the meshing state of the first gear 40 and the second gear 41.

In such a configuration, if the gear ratio between the second gear 41 and the first gear 40 is N:1, by rotating the fine adjustment screw 42 by N, the first gear 40 rotates once. Therefore, fine adjustment of the frequency is possible.

[0031] Also in this second embodiment, the housing 1
Since only the nuts 21 and 43 protrude from the 0, when this microwave oscillator is incorporated into a communication device or the like, the entire device can be made smaller than before.

Furthermore, instead of the first gear 40, a disc 35 having the shape shown in FIGS. 4 and 5 may be provided with teeth.

[0033]

[Effects of the Invention] As explained above, according to the microwave oscillator of the present invention, the protruding portion from the housing can be minimized, so when it is incorporated into a communication device, etc.
This has the effect of reducing the size of the entire device.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of the present invention.

FIG. 2 is a sectional view showing the configuration of a microwave oscillator according to a first embodiment of the present invention.

FIG. 3 is a bottom view of a disc of the frequency adjustment means shown in FIG. 2;

FIG. 4 is a cross-sectional view showing a disk structure having a shape other than the disk of the frequency adjustment means shown in FIG. 2;

FIG. 5 is a bottom view of the disk shown in FIG. 4;

FIG. 6 is a sectional view showing the configuration of a microwave oscillator according to a second embodiment of the present invention.

7 is a plan view showing the meshing of the first gear and the second gear of the frequency adjusting means shown in FIG. 6; FIG.

FIG. 8 is a cross-sectional view showing the configuration of a conventional microwave oscillator.

9 is a schematic configuration diagram of a microwave oscillation circuit configured on a dielectric substrate of the microwave oscillator shown in FIG. 8. FIG.

[Explanation of symbols]

1 Housing 2 Dielectric substrate 3 Support stand 4 Dielectric resonator 5 Microstrip line 6 Nut 7 Threaded part 8 Disk

Claims (2)

[Claims] Claim 1: A dielectric resonator (4) is fixed on a dielectric substrate (2) fixed in a metal casing (1) via a support base (3), and the dielectric resonator (4) is Resonator (4)
An oscillation circuit consisting of a microstrip line (5), an active element, and a passive element is constructed in the vicinity, and a through hole formed in the housing (1) above the dielectric resonator (4) is connected to the microstrip line (5). When inserted, the metal screw part (7) serving as a frequency adjustment means screwed into the nut (6) on the through hole is rotated, and the lower end surface of the screw part (7) and the dielectric resonance are rotated. (4) In a microwave oscillator whose frequency is changed by adjusting the distance from the upper surface, the frequency adjusting means is connected to the nut (6), a threaded part (7) screwed into the dielectric resonator, and the dielectric resonator. (4) The screw portion (7) is arranged upwardly, and the metal disk (8) is fixed to the lower end and has a thickness that varies along the circumference. ) When rotating, the threaded part (7)
A microwave oscillator characterized in that the length of the nut (6) does not protrude from the nut (6). 2. The microwave oscillator according to claim 1, wherein the disc (8) is formed into a gear shape, and a fine adjustment screw having a gear meshing with the teeth of the disc (8) is provided.