JPS5885601A - Microstrip type band-pass filter - Google Patents

Abstract

PURPOSE:To make a titled band-pass filter small-sized and light, by constituting so that adjacent resonators are coupled by a line of prescribed length of center frequency, and also resonators which have been separated from each other by >=1 stages are coupled. CONSTITUTION:A polarized band-pass filter of three stages is constituted by providing an electric conductor pattern 10 on a dielectric substrate 9, and as for a resonator, a parallel stub type which is short-circuited in one end and is opened in the other end, and has 1/4 wavelength lambdag or 3/4lambdag is used. Eacg resonator is connected by a strip line of length of 1/4lambdag, stub resonators of the first and the third stages are bent, a part of about 1/4lambdag from the opening end is made to stand close, and the first and the third stages are coupled, by which the poarized band-pass filter is realized. Adjacent resonators are generally coupled by a line of (2n+1)/4lambdag (n is ''0'' or a positive integer). In this way, a titled band- pass filter which is small-sized and light can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microstrip lid bandpass filter 11 that provides good frequency selectivity in microwave circuits.

Conventionally, a polar filter #IL device with ripple characteristics in the pass band and stop band has been used as a non-polar filter II with the same number of stages.
Has better frequency characteristics than IK, so it can be used over a wide range of 111
The sounds used are.

1 and 2 show conventional polarized bandpass filters in the microwave band.

Figure 1-) and false) are the front view and cross-sectional view of the Oka shaft lid filter, respectively, where 1 is the filter housing and coaxial resonator outer conductor, 2111 to ZdtiFJ shaft resonator center conductor, 3 &
3d is an inter-resonator coupling hole, 4 is an input/output coaxial path, and 5 is a coupling probe.

On the other hand, Fig. 2 is a perspective view of the waveguide layer filter O, where the square waveguide resonator is shown at the white end, and the inter-resonator coupling hole 71 to 7d is the coupling hole between the input/output waveguide and the resonator. It is a hole. Such a coaxial m or waveguide violet filter has the advantage that high Qo can be obtained and one-pass loss can be reduced, but on the other hand,
Since it is a three-dimensional structure, the small lid can be made lightweight, but it has the drawback of increasing the number of parts and increasing manufacturing costs.

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to create a micro-liquid polarized bandpass filter that uses a microstrip line and has a planar structure that can reduce the weight of the small lid, without using a three-dimensional circuit structure such as a coaxial entwined waveguide line. We provide wave equipment.

In order to achieve the above object, in the microstrip bandpass filter according to the present invention, a nine-stage bandpass filter using parallel stub resonators formed by a microstrip line, the central circumferential frequency between adjacent resonators is The structure is such that nine resonators are connected by a line having a length of (2n+1)/4 wavelength (n is a positive integer), and nine resonators are separated by 11 stages or more.

Therefore, it is possible to construct a polarized filter with a small lid that is lightweight and low in cost.

below,! Micros according to the invention with reference to III)
The IJ-equipped bandpass filter will be explained in more detail.

FIG. 3 shows one embodiment of the present invention, FIG. 3 (&) shows a normal mm, and FIG. 3 (E) shows a side view.

In the figure, 9 indicates a dielectric substrate, and 10 indicates a conductor pattern. In this embodiment, a 13-stage polar bandpass filter is constructed. As a resonator, one end is short-circuited and the other end is open. /4
Connect the wave length (λg) or 3/4 length between the resonators with an IJ tube line with a length of 1/4λg, and fold the 1st and 3rd stage stub resonators into the open end. By placing the 1/4 λg portions close to each other, the 11th and 3rd R are coupled to realize a multi-polar bandpass filter.

Note that the coupling between adjacent resonators is generally (2n+1)741
g (m is O or a positive integer) line.

Figure 4 shows another embodiment of the present invention. 9 is a dielectric substrate, and 10 is a conductor pattern.

A three-stage polar bandpass filter using a stub resonator with one end shorted and one end open is constructed.The first stage and 111E31R
In order to obtain resonance-〇 coupling with
Moreover, the weight of about 1/41g of the tip is placed close to the tip.

The fifth wI shows yet another embodiment of the present invention.

9 is a dielectric substrate, and 10 is a conductor pattern.

This is a 4R polar bandpass filter.

The conductor pattern of the microstrip line in one or more of the embodiments can be formed using photo-etching techniques.

Since the actual bandpass filter is constructed as described above, it is small and lightweight, and can be manufactured in large numbers at once, reducing manufacturing time from scratch. Costs can be significantly reduced.

[Brief explanation of the drawing]

1st Khiro shows a conventional coaxial type polarized bandpass filter, 1st 11C shows a positive polarity, and 1st (bl is purchased by Yubu). 2nd figure shows a conventional coaxial type polarized bandpass filter. FIG. 3 is a perspective view of a band-pass filter.
&), No. 41! 1 (Xun, Hall 5 (Xun is each front view,
FIG. 3 (noodles, FIG. 4(b), FIG. 5~) are sectional views thereof. 9... Dielectric substrate 10... Conductor Figure 1 (6) (b) Figure 2 Figure 5 Figure 4 (a) (b) Figure 5 (a) (b)

Claims (1)

[Claims] In a multi-bandpass filter using parallel stub resonators using microstrip lines, the length of adjacent resonances is set to center frequency 0 (2n + 1) and 74 wave members (n is O★e is a positive integer). ◇