JPH03129907A - Microwave oscillator - Google Patents

Abstract

PURPOSE:To prevent an oscillating signal generated by a surface wave mode from leaking to the outside of an oscillator, and to constitute other circuit and an oscillating circuit on the same substrate by providing a through-hole for allowing the upper and the lower ground conductors of a dielectric substrate to conduct. CONSTITUTION:On a dielectric substrate 3 of the part inserted and held by the upper and the lower m tallic cases 5, 6, a through-hole 2 is provided in a line on one straight line. By this through-hole 2, ground conductors 1, 4 of the upper and the lower faces of the dielectric substrate 3 are allowed to conduct. An interval l of the through-holes is set to <=lambdag/2 against a fundamental frequency lambdag. According to such a constitution, a wall of the ground conductor is formed approximately, and it can be prevented that an oscillating signal leaks to the outside of an oscillator. Also, when a second higher harmonic is also taken into consideration against the fundamental oscillation frequency, l<=lambdag/4 is set against the interval of the through-hole.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microwave oscillator used in an SHF receiver or an R(S converter) for receiving satellite broadcasting.

[Prior art] Recently, as a microwave oscillator, as an oscillation element,
It uses a GaAsFET, is mounted on an oscillation circuit pattern formed on a dielectric substrate, and is surrounded by a metal case. In order to stabilize the oscillation frequency, the dielectric resonator is housed in a metal case, and the oscillation frequency is generally adjusted by inserting metal screws into the metal case.

There are various methods of surrounding the oscillation circuit with a metal case, but here, a configuration is used in which the metal case can be separated by a dielectric substrate. FIG. 3 shows a perspective view of the upper metal case 5 of the microwave oscillator.

Further, FIG. 4 shows a sectional view of a conventional example. Dielectric substrate 3
A dielectric resonator 7 made of a GaAsFET or the like is provided on the dielectric resonator 7, and an oscillation circuit pattern is formed on the upper surface of the dielectric substrate 3 around the dielectric resonator 7. and,
Around the oscillation circuit pattern, surrounding the pattern,
A ground conductor 1 is formed, and the lower surface of the dielectric substrate 3 is completely covered with a ground conductor 4. This dielectric substrate 3
It is fixed to the upper metal case 5 and the lower metal case 6 with screws 10 with the two sides in between. At the center of the upper part of the metal case 5, a metal screw 8 for adjusting the oscillation frequency is provided with a nut 9, corresponding to the dielectric resonator 7. moreover,
Several through holes are formed between the upper surface of the dielectric substrate 3 and the ground conductor 1.4 on the lower surface for grounding.

[Problems to be Solved by the Invention] In such a conventional example, there is no problem when the oscillation frequency is low, but as the oscillation frequency becomes higher, the oscillation signal becomes more difficult to reach through the microstrip line, as shown by the arrow in FIG. It is thought that the leakage occurs outside the oscillator in a non-quasi-TEM transmission mode, that is, in a surface wave mode in the dielectric sandwiched between the upper and lower ground planes of the dielectric substrate 3.

The present invention has been provided in view of the above points, and includes:
The present invention provides a microwave oscillator whose purpose is to prevent an oscillation signal from leaking out of the oscillator in surface wave mode.

[Means for Solving the Problems] The present invention has a through hole arranged in a row to establish continuity between the ground conductors on the upper and lower sides of a dielectric substrate6. The oscillation signal generated by the surface wave mode is prevented from leaking outside the oscillator.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. still,
The overall configuration is the same as before. Figures 1(a) and 2
As shown in the figure, through holes 2 are arranged in a straight line in a portion of the dielectric substrate 3 sandwiched between the upper and lower metal cases 5.6. This through hole 2 allows the dielectric substrate 3
The ground conductors 1.4 on the upper and lower surfaces of the FIG. 1(a) shows the case where there is one row of through holes 2,
Spacing between through holes 2! is λg for the fundamental frequency λg
/2 or less. With this configuration, a wall of ground conductor is approximately formed, and leakage of the oscillation signal to the outside of the oscillator can be prevented.

Also, considering the second harmonic liquid for the fundamental oscillation frequency,
For the spacing l of through hole 2, ! ≦λg/4.

Furthermore, if higher harmonics are taken into consideration, it becomes impossible to construct a row of through holes 2 with very short intervals, so as shown in Figure 1 (
As shown in b), there are two rows of through holes 2, and one
If the row of through holes 2 in the second row is configured so as to fill the gaps in the through holes 2 in the row, then l≦λg/4, 4
All oscillation signals up to the next harmonic component can be prevented from leaking out of the oscillator. Note that two or more rows of through holes 2 may be provided.

Incidentally, as a technique for grounding the top surface conductor, generally through holes are used, but the present invention is characterized in that through holes are provided periodically to prevent leakage of oscillation signals.

[Effects of the Invention] As described above, the present invention has through holes arranged in a row to establish continuity between the ground conductors on the upper and lower sides of a dielectric substrate. It is possible to prevent leakage outside the oscillator of Hayabusa. Therefore, in order to completely surround the oscillation circuit with a metal case, it is necessary to separate the oscillation circuit board from other circuit boards. According to the present invention, another circuit and an oscillation circuit can be formed on the same substrate.

[Brief explanation of the drawing]

FIG. 1(a) is a perspective view of a main part of an embodiment of the present invention, FIG.
b) is a perspective view of a main part of another embodiment same as the above, FIG. 2 is a sectional view of the embodiment of the present invention, FIG. 3 is a perspective view of a conventional example, and FIG. 4 is a sectional view of the same. 1 is a ground conductor, 2 is a through hole, 3 is a dielectric substrate, 4
is a ground conductor, and 5.6 is a metal case.

Claims (1)

[Claims] (1) On the top surface of the dielectric substrate whose bottom surface is covered with a ground conductor,
Components such as an oscillation element and an oscillation circuit pattern are mounted, a ground conductor is provided on the upper surface of the dielectric substrate around the oscillation circuit pattern, a metal case is arranged so as to be in contact with this ground conductor, and the metal case is 1. A microwave oscillator that can be separated by a dielectric substrate, characterized in that a through hole is arranged in a row to establish continuity between ground conductors above and below the dielectric substrate.