JPH07115322A - Microwave oscillating device - Google Patents

Abstract

PURPOSE:To enable even a beginner to quickly and accurately control the frequency by changing the thickness of the piezoelectric cermaics to control the distance between the upper surface of an oscillator and a metallic bar. CONSTITUTION:A dielectric oscillator 1 is mounted on an antenna base board 5. A piezoelectric ceramics 3 containing the electrodes 2a and 2b on its upper and lower surfaces is provided between the upper surface of the oscillator 1 and a cavity 6 with the ceramics 3 fixed to the side wall of the cavity 6. The lower electrode 2b is provided with a metal piece 4 at a position opposite to the oscillator 1. The distance between the metal piece 4 and the upper surface of the oscillator 1 is mechanically changed by the ceramics 3 in the order of several 10mum. Then the currents supplied to both electrode 2a and 2b from a power unit 7 are controlled by a volume switch 7a. Thus the oscillation frequency can be controlled in steps.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oscillating device used in, for example, a microwave sensor unit and the like, and more specifically to a microwave oscillating device having a function of adjusting its oscillation frequency.

[0002]

2. Description of the Related Art In a microwave oscillating device, as shown in FIG. 5, a dielectric oscillator 73 is mounted on an antenna substrate 74 in a cavity 72, and the cavity 72 immediately above the dielectric oscillator 73 is The structure is such that an adjusting screw 71 that moves up and down is provided. This adjustment screw 71
The oscillation frequency can be finely adjusted by vertically moving the.

When using a plurality of sensors equipped with such a microwave oscillating device, for example, in the same area as a door sensor, it is necessary to prevent malfunction due to mutual interference. As a countermeasure against this, conventionally, a plurality of sensors having the same type but different oscillation frequencies are prepared in advance, and they are provided in the same region.

[0004]

By the way, in the prior art, when finely adjusting the oscillation frequency, the interval for moving the screw up and down must be within a range of several tens of μm, and this work is done by changing the position of the adjusting screw. Since it is a manual fine adjustment such as tightening with nuts etc. to fix the position after matching,
In addition to being time-consuming, it is not easy for the user to handle, and there is the inconvenience of having to rely on the experience of experts. On the other hand, even when a plurality of sensors having different oscillation frequencies are already provided without performing such difficult fine adjustment, only the frequency is different for the same product, and management by product type is required for production, sales, installation, etc., which is complicated. In addition, there is a problem that the cost becomes high.

The present invention has been made in order to solve these problems, and microwaves that can adjust the frequency accurately in a short time even by an inexperienced person, regardless of the experience of a skilled person. It is an object to provide an oscillator.

[0006]

In order to achieve the object of the present invention, a microwave oscillating device of the present invention has an oscillator for oscillating a microwave of a predetermined frequency and a cavity covering the oscillator on a substrate. In a provided microwave oscillating device, piezoelectric ceramics, wherein electrodes are provided on the upper surface and the lower surface of the oscillator between the oscillator and the cavity above the oscillator, and a metal piece is provided on the lower surface of the electrode on the lower surface side. Is provided, and a power supply unit that supplies a current to each of the electrodes and an adjusting unit that adjusts the current value from the power supply unit are provided.

[0007]

The distance between the upper surface of the oscillator and the metal piece provided on the lower surface electrode of the piezoelectric ceramics is a factor that determines the oscillation frequency. The present invention utilizes the fact that the piezoelectric ceramic has piezoelectricity. That is, when a current is applied to the piezoelectric ceramics, the thickness of the piezoelectric ceramics changes according to the value of the current, so that the distance between the oscillator upper surface and the metal piece can be adjusted.

By changing the distance in this way, the oscillation frequency can be finely adjusted.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 (a) is a configuration diagram of the embodiment of the present invention, and FIG.
FIG. 4A is a sectional view taken along line AA in FIG.

A dielectric oscillator 1 is mounted on an antenna substrate 5, and a cavity 6 for covering the dielectric oscillator 1 is provided. This dielectric oscillator 1 upper surface and cavity 6
In between, piezoelectric ceramics 3 having electrodes 2a and 2b formed on the upper and lower surfaces thereof are arranged in a state of being fixed to the side wall of the cavity 6. Further, a metal piece 4 is provided on the lower surface electrode 2b at a position facing the dielectric oscillator 1. The distance between the metal piece 4 and the upper surface of the dielectric oscillator 1 is usually 2 to 3 mm, and the piezoelectric ceramic 3 causes mechanical fluctuation in the order of several tens of μm. The electrodes 2a and 2b are electrically connected to the power supply device 7, and a predetermined current is supplied from the power supply device 7 as described later. That is, the power supply device 7 is provided with the volume switch 7a for adjusting the current to be supplied. This volume switch 7a, as shown in FIG.
It is a three-stage switch of "L", "M", and "H". A circuit diagram thereof is shown in FIG. When the volume switch 7a is set to "L", "M", or "H", a predetermined current is supplied from the power supply device by each set circuit.

The microwave oscillating device having the above structure is
As an example of its use, as shown in FIG. 4, for example, it is mounted on a patch antenna, and the oscillation frequency can be easily step-adjusted. Although the step switch is provided in the embodiment of the present invention, other adjusting means may be used as long as the current to be supplied can be adjusted.

[0012]

As described above, according to the microwave oscillating device of the present invention, electrodes are provided on the upper surface and the lower surface between the oscillator and the cavity above the oscillator, and the electrode on the lower surface side. A piezoelectric ceramics provided with metal pieces is disposed on the lower surface of each of the electrodes, and a power supply unit for supplying a current to each electrode and an adjusting unit for adjusting the current value from the power supply unit are provided. Therefore, if the step is appropriately set by the adjusting means, it is possible to easily and accurately adjust the oscillation frequency in a short time. As a result,
The oscillation frequency can be adjusted even by an inexperienced person without depending on the experience of a skilled person as in the past, and the adjustment by an end user such as mounting a sensor becomes possible. Further, the manufacturing side does not need to manufacture the same product having different oscillation frequencies, and it is sufficient to manufacture the same product, so that the cost does not increase.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is an explanatory view of the operation of the embodiment of the present invention.

FIG. 3 is a circuit diagram of a current adjusting volume applied to an embodiment of the present invention.

FIG. 4 is an external view of an application example of the embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view showing the configuration of a conventional example.

[Explanation of symbols]

 1 ... Dielectric oscillator 2a, 2b ... Electrode 3 ... Piezoelectric ceramics 4 ... Metal piece 5 ... Antenna substrate 6 ... Cavity 7 ... Power supply device 7a ... Volume switch

Claims (1)

[Claims] 1. A microwave oscillating device having an oscillator for oscillating a microwave of a predetermined frequency on a substrate and a cavity for covering the oscillator, wherein the oscillator is provided between the oscillator and the cavity above the oscillator. Piezoelectric ceramics provided with electrodes on the upper and lower surfaces, and metal pieces provided on the lower surface of the electrode on the lower surface side, a power supply unit for supplying current to each of the electrodes, and a power supply therefor. A microwave oscillating device comprising: an adjusting unit for adjusting a current value from the supply unit.