JP2005102046A - Band-pass filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a band-pass filter capable of having a wide passband width and improved spurious characteristics. <P>SOLUTION: The band-pass filter 1 is provided with a body 2 and a cover 3 which are dividable at one E surface 8B, a plurality of irises 4 arranged inside the body 2, and at least one spurious adjusting screw 9 capable of projecting immediately above at least one out of the plurality of irises 4 from the cover 3. A frequency adjusting screw 6 for adjusting the transmission frequency of a waveguide by its projecting length into the body 2, and a degree of coupling adjusting screw 7 for adjusting the degree of coupling the waveguide by its projecting length into the body, can be provided. It does not matter if the plurality of irises 4 are arranged so as to touch the E surface 8A. It is also possible to arrange the irises so as not to touch both E surfaces 8A, 8B. It does not matter if the irises are arranged symmetrically or asymmetrically with respect to the center line of the waveguide, and it is also possible to combine asymmetrical irises 4 with symmetrical irises 4 when they are arranged so as not to tuoch. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a band-pass filter, and more particularly to a band-pass filter that is used in a microwave transmission line and obtains a band-pass characteristic by an inductive window.

  Some bandpass filters used in conventional microwave transmission lines obtain bandpass characteristics by an inductive window. As an example of this bandpass filter, for example, as shown in FIG. 5, a bandpass filter described in Patent Document 1 includes a main body 22 and a cover 23 that can be divided into two on one E surface 28B, and the other E surface 28A. And a space (resonator) 25 partitioned by an iris (conductor plate) 24 whose one side is short-circuited.

  The bandpass filter 21 configured as described above has a stable non-contact structure because the iris 24 and the cover 23 have a completely non-contact structure. Furthermore, as shown in FIG. 6, by providing the band pass filter 21 with a frequency adjusting screw 26 and a coupling degree adjusting screw 27, it is possible to adjust to a desired characteristic.

Japanese Patent No. 3025930

However, in the conventional band-pass filter 21, the opening (gap) between the cover 23 and the iris 24 is wide enough to allow the TE ₂₀ mode, which is the mode immediately above the fundamental wave, to pass, so that it is spurious at high frequencies. There was a problem that the characteristics deteriorated. This problem becomes more prominent especially when the passband width is wide. Here, if the opening is narrowed to such an extent that the TE ₂₀ mode does not easily pass, there is a problem that a wide pass bandwidth cannot be obtained. On the other hand, when the pass band width is widened, the opening becomes wider, so that there is a problem that spurious is likely to occur.

  Therefore, the present invention has been made in view of the problems in the conventional bandpass filter described above, and provides a bandpass filter with a wide passband width and improved spurious characteristics. Objective.

  In order to achieve the above object, the present invention is a band-pass filter, which is a main body and a cover that can be divided on one E surface, a plurality of irises arranged inside the main body, and the plurality of irises from the cover. And at least one spurious adjusting screw capable of projecting immediately above at least one of the irises.

  According to the present invention, the spurious adjustment screw is inserted into the waveguide from the E plane side, so that the opening at the end of the waveguide can be equivalently reduced. It becomes possible to make it difficult to let a wave pass.

  Also, a frequency adjusting screw for adjusting the transmission frequency of the waveguide by the length protruding into the main body and a coupling degree adjusting screw for adjusting the degree of coupling of the waveguide by the length protruding inside the main body are provided. Can do.

  Further, the plurality of irises may be brought into contact with an E surface different from the E surface on which the main body and the cover can be divided, and the iris may be brought into non-contact with both the E surfaces.

  If the plurality of irises are not in contact with both E planes, the opening can be divided into both sides, so that each opening can be made smaller, and when compared with the same pass bandwidth, harmonics are generated. It becomes difficult to pass through and spurious characteristics can be improved. In this case, a plurality of irises can be arranged asymmetrically or symmetrically with respect to the center line of the waveguide.

  Further, the plurality of irises are brought into contact with an E surface different from the E surface from which the main body and the cover can be divided, are not in contact with both E surfaces, and are arranged asymmetrically with respect to the center line of the waveguide. And at least two selected from those arranged in non-contact with both E planes and arranged symmetrically with respect to the center line of the waveguide.

  As described above, according to the present invention, it is possible to provide a bandpass filter that can widen the passband width and improve the spurious characteristics.

  1 and 2 show an embodiment of a band-pass filter according to the present invention. This band-pass filter 1 is divided into a main body 2 made of a conductive material and open on both side surfaces, and one E surface 8B. The cover 3 is made of a conductive material that covers the opening of the main body 2 and is formed integrally with the main body 2, and is in contact with the E surface 8A and the H surfaces 10A and 10B, and is not in contact with the E surface 8B. A plurality of resonators 5 are continuously formed.

  In addition, the band pass filter 1 includes a plurality of frequency adjusting screws 6 that can adjust the transmission frequency of the waveguide by the length protruding into the main body 2, and the waveguide according to the length protruding into the main body 2. Are provided with a plurality of coupling degree adjusting screws 7 capable of adjusting the degree of coupling. By these, the band pass filter 1 can be adjusted to a desired characteristic. The frequency adjusting screw 6 and the coupling degree adjusting screw 7 shown in the figure are not all necessary, and can be arranged only in necessary places.

  Further, the band pass filter 1 is provided with a spurious adjusting screw 9 immediately above the iris 4 from the cover 3. The feature of the present invention is that the spurious adjusting screw 9 is provided. The spurious adjustment screw 9 can attenuate and adjust the spurious. The number of spurious adjusting screws 9 can be reduced depending on desired characteristics.

  Next, the operation of the bandpass filter 1 having the above configuration will be described.

  The bandpass filter 1 and the conventional bandpass filter 21 shown in FIG. 6 have the same configuration except for the spurious adjustment screw 9. Therefore, the basic operation is also the same. However, in the conventional band pass filter 21, since the iris 24 is in contact with the E surface 28A on one side, the opening portion is concentrated at one end and becomes wider. On the other hand, in the band-pass filter 1 according to the present invention, the opening can be equivalently reduced by inserting the spurious adjusting screw 9 into the waveguide from the E surface 8B side. For this reason, it is difficult for spurious to pass through the opening.

  As an example, FIG. 3 shows a broadband pass characteristic in the 18 GHz band of each of the bandpass filters of the prior art and the present invention. The waveform of the bandpass filter 1 according to the present invention shown in the figure is the case where two spurious adjusting screws 9 are used, and it can be confirmed that the spurious characteristics are improved. In addition, the greater the number of spurious adjustment screws 9, the greater the effect.

  FIG. 4 shows another embodiment of the band-pass filter according to the present invention. The band-pass filter 11 is made of a conductive material, and can be divided into a main body 12 having both side surfaces open and both E surfaces 18A and 18B. The cover 13 (13A, 13B) made of a conductive material that covers the opening of the main body 12 and the main body 12 are formed integrally with the H surface 20A, 20B, and both the E surfaces 18A, 18B. A non-contact iris 14 is provided, and a plurality of resonators 15 are continuously formed.

  The band pass filter 11 is also provided with a frequency adjusting screw 6, a coupling degree adjusting screw 7, and a spurious adjusting screw 19 in the same manner as the band pass filter 1 shown in FIG. It is possible to adjust to a desired characteristic and to attenuate and adjust the spurious.

  Since the iris 14 is not in contact with both the E surfaces 18A and 18B, the band pass filter 11 can divide the opening into both sides, so that each opening can be made small and the same pass band can be obtained. When compared by width, harmonics are difficult to pass. Thereby, spurious characteristics can be further improved.

  In the band-pass filter 11 of FIG. 4, the iris 14 is arranged in the center of the waveguide so as to be symmetric. However, if the iris 14 is not in contact with both E surfaces 18A and 18B, An asymmetric arrangement is also possible. It is also possible to combine the symmetric arrangement and the asymmetric arrangement of the iris 14, and it is also possible to combine the asymmetric structure of the iris 4 in FIG. 1 and the symmetric structure of the iris 14 in FIG. In FIG. 4, the spurious adjustment screw 19 is provided on the E surface 18B side, but it may be provided on the E surface 18A side.

It is a figure which shows one Embodiment of the band pass filter concerning this invention, Comprising: (a) is a front view which shows the state which removed the cover, (b) is a longitudinal cross-sectional view. It is a disassembled perspective view of the band pass filter of FIG. It is the graph which compared the characteristic of the bandpass filter concerning this invention, and the conventional bandpass filter. It is a figure which shows other embodiment of the bandpass filter concerning this invention, Comprising: (a) is a front view which shows the state which removed the cover, (b) is a longitudinal cross-sectional view. It is a figure which shows an example of the conventional band pass filter, Comprising: (a) is a front view which shows the state which removed the cover, (b) is a longitudinal cross-sectional view. It is a figure which shows an example of the conventional band pass filter, Comprising: (a) is a front view which shows the state which removed the cover, (b) is a longitudinal cross-sectional view.

Explanation of symbols

1 Band pass filter 2 Body 3 Cover 4 Iris (conductor plate)
5 space (resonator)
6 Frequency adjusting screw 7 Coupling degree adjusting screw 8 (8A, 8B) E surface 9 Spurious adjusting screw 10 (10A, 10B) H surface 11 Band pass filter 12 Main body 13 (13A, 13B) Cover 14 Iris (conductor plate)
15 space (resonator)
16 Frequency adjusting screw 17 Coupling degree adjusting screw 18 (8A, 8B) E surface 19 Spurious adjusting screw 20 (10A, 10B) H surface

Claims (7)

A main body and a cover that can be divided on one E surface;
A plurality of irises arranged inside the body;
A band-pass filter comprising: at least one spurious adjustment screw that can protrude from the cover directly above at least one of the plurality of irises. The band pass filter according to claim 1, further comprising a frequency adjusting screw for adjusting a transmission frequency of the waveguide by a length protruding into the main body. 3. The band-pass filter according to claim 1, further comprising a coupling degree adjusting screw for adjusting a coupling degree of the waveguide by a length protruding into the main body. 4. The bandpass filter according to claim 1, wherein the plurality of irises are brought into contact with an E surface different from an E surface on which the main body and the cover can be divided. 4. The bandpass filter according to claim 1, wherein the plurality of irises are disposed in a non-contact manner on both E surfaces and are asymmetrically arranged with respect to a center line of the waveguide. 4. The bandpass filter according to claim 1, wherein the plurality of irises are arranged in a non-contact manner on both E surfaces and symmetrically arranged with respect to a center line of the waveguide. The plurality of irises are in contact with an E surface different from the E surface from which the main body and the cover can be divided, non-contact with both E surfaces, and asymmetrically arranged with respect to the center line of the waveguide 4. The band according to claim 1, 2 or 3, wherein the band is composed of at least two selected from those arranged in non-contact with both E planes and arranged symmetrically with respect to the center line of the waveguide. Pass filter.

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