JPS5942733Y2 - microwave bandpass filter - Google Patents

Description

[Detailed description of the invention] The present invention relates to a microwave filter, and in particular, a microwave band pass for a microwave synthesizer having a plurality of microwave filters made by providing a metal plate in a waveguide. It concerns a filter.

Conventionally, this type of microwave synthesizer includes waveguide coaxial transducers 1 and 2 (hereinafter referred to as transducers) having input terminals for f1 and f2, as shown in FIG.
A bandpass filter 3.4 and 2 that passes fl and f2.
It consisted of two waveguide circulators 5°6.

In the microwave synthesizer configured in this manner, the signal t1tt applied to the transducer 1 is filtered by the filter 3.
The signal is then transmitted through two waveguide circulators 5 and 6 to the bandpass filter 4, where the bandpass filter 4 has a good pass characteristic for the signal f2, but it is transmitted to the bandpass filter 4 for signals other than f2. Since the signal has the property of being reflected, the signal f1 is reflected by the bandpass filter 4 and appears at the output terminal 8.

On the other hand, the signal f2 applied to the transducer 2 passes through the bandpass filter 4 and the waveguide circulator 6 and is transmitted to the output terminal 8.

That is, Fo, f2 applied to two different input terminals
The signals are combined and appear at the output terminal 8.

Here, the terminator 7 is for absorbing reflected waves due to mismatch at the output terminal.

A microwave synthesizer having such a configuration is in line with the recent trend of downsizing of microwave devices, and has been an obstacle to downsizing of microwave devices.

An object of the present invention is to provide a compact microwave band-pass filter in which two microwave band-pass filters are arranged in one waveguide.

The present invention will be described in detail with reference to the drawings below.

FIG. 2 is an external view of the microwave bandpass filter of the present invention.

Figure 3 is a cross-sectional view of the X plane in Figure 2. Figure 4 is the Y-plane in Figure 3.
It is a sectional view of the Y plane.

Identical parts are given the same reference numerals.

A metal shielding plate 10 is arranged approximately in the center of the waveguide 9 with one end short-circuited so as to be parallel to the electric field and perpendicular to the magnetic field, and cut-off waveguides 1 on both sides separated by the metal shielding plate 10 are arranged.
1.12 semi-coaxial resonators 13-1-5 and 13'-15
or is formed.

If there is no resonator, this cut-off waveguide has an input wave f
1 to f2, the input wave is exponentially attenuated and is not transmitted to the output side.

However, if there is a resonator in the cut-off waveguide, the input wave can be coupled to this resonator and propagated to the output side.

This process will be explained with reference to FIG. 3. The signal f□ entering the input terminal 19 is coupled to the first coax 20. This coax 20 acts as an impedance transformer.

This coaxially coupled signal is coupled to the resonators 13, 14, 15 one after another and coupled to the coaxial 21 on the output side.

With this structure of switch 1, signals cannot be coupled to the waveguide.

In other words, in coaxial mode and waveguide mode, the magnetic fields are orthogonal, and the electric fields are parallel to each other, but in coaxial mode, they are symmetrical about the axis, so it is necessary to distort the coaxial mode and sharpen the parallel part of the electric field. .

The connection adjustment screw 22 performs this function.

This coupling adjustment screw 22 is provided almost above the coaxial 21,
This screw 22 is adjusted to adjust the coupling between the coaxial filter and the output waveguide.

The screw 23 is for finely adjusting the entire coupling on the input side.

Screws 25, 26 are for adjusting the coupling between coaxial resonators 13, 14, 15, and screws 24, 27 are for adjusting the coupling between the input side coax and coaxial resonator 13, the output side coax and coaxial resonator 15, respectively. It is for adjustment.

By changing these screws 22r27, the passband of the coaxial filter can be adjusted.

Numerals 28 to 30 are fine adjustment screws for adjusting the respective tuning frequencies by changing the substantial length of the coaxial resonator.

The same thing can be said about the coaxial filter on the f2 side.

Parts having the same effect are indicated by the same symbol followed by [.]. 6 As described above, fl applied to the two input terminals.

f2 is coupled to the same output waveguide for all coaxial filters.

That is, the two signal waves are combined on the output side.

As shown in Figure 5, the microwave synthesizer using this microwave bandpass filter is simply a combination of the microwave bandpass filter of the present invention and a waveguide circulator, and is approximately half of the conventional configuration. I was able to do it.

Another major advantage of such a configuration is that delay time characteristics are improved.

In FIG. 1 of the conventional configuration, the delay time characteristic of the signal f1 is affected by the out-of-band reflection characteristics of the microwave bandpass filter for f2, and the delay time characteristic is, for example, 1 to 3 ns at f0±10MH2.
undergoes a first-order slope of .

However, in FIG. 5 of the present invention, there is no influence of reflection on both fl and f2, so there is almost no linear slope of the delay time characteristics.

In the above description, a microwave synthesizer has been described, but the present invention can also be used in a microwave demultiplexer.

[Brief explanation of drawings]

Fig. 1 is an example of a microwave synthesizer, Fig. 2 is an external view of the microwave bandpass filter of the present invention, Fig. 3 is a cross-sectional view taken along the X-ray in Fig. 2, and Fig. 4 is a Y in Fig. 3. FIG. 5, a sectional view taken along the -Y plane, shows a microwave synthesizer using the microwave bandpass filter of the present invention. In the figure, 12 is a waveguide coaxial transducer;
4 is a bandpass filter, 5.6 is a waveguide circulator,
7 is a terminator, 8 is an output terminal, 9 is a waveguide, 10 is a metal shield, 11.12 is a cut-off waveguide, 13, 14, 1
5,13. '14. '15' is the resonator, 19.19' is the input terminal, 20, 20121, 21' is the coaxial, 22.2
2?23.23' is a coupling adjustment screw, 24.25°26.
27.24C25C26: 27' is a coupling adjustment screw, 28
~30.28'-30' are fine adjustment screws.

Claims (1)

[Scope of utility model registration request] At least one semi-coaxial resonator parallel to the waveguide's magnetic field in each of two or more cutoff waveguides formed by metal shielding plates placed parallel to the electric field in a waveguide short-circuited at one end. A microwave bandpass filter characterized by having the above arrangement.