CN100399081C - Substrate Integrated Waveguide Balanced Filter - Google Patents

Abstract

The substrate-integrated waveguide balanced filter is a substrate-integrated waveguide balanced filter that can be applied to the design of microwave and millimeter-wave circuits, and can also be used in the design of microwave and millimeter-wave integrated circuits. The filter metal patch (1) is set on On the dielectric substrate (2), the middle part of the metal patch (1) as the main body of the filter is rectangular, and the two ends are symmetrically called "Y"-shaped ports, and the two sides of the rectangular middle part of the metal patch (1) are respectively There is a row of first metal through holes (31) and second metal through holes (32), and between the two rows of metal through holes, there are three sections parallel to the two rows of metal through holes on the center line of the rectangular metal patch. The third metal through hole (33), the fourth metal through hole (34), the fifth metal through hole (35), on both sides of the centerline of the rectangular metal patch, there are also 4 pairs of intermediate metal through holes symmetrically, along the The direction from the input end (4) to the first isolation end (5) is arranged.

Description

Substrate Integrated Waveguide Balanced Filter

technical field

The invention is a substrate-integrated waveguide balanced filter that can be applied to the design of microwave and millimeter wave circuits and can also be used in the design of microwave and millimeter wave integrated circuits, belonging to the technical field of microwave filters.

Background technique

Microwave and millimeter wave filters are at the center of many design issues in microwave and millimeter wave RF systems such as frequency converters, frequency multipliers, and multiplex communications. The electromagnetic spectrum is limited and must be allocated according to the application; the filter can be used to radiate in the specified frequency band with an unrestricted high-power transmitter, and in turn can be used to prevent the receiver from being interfered with outside the operating frequency band. In addition to selecting the frequency to pass through, the balanced filter can prevent the signal at the stop band frequency from being reflected back to the input terminal through the principle of interference. Metal waveguides can be used to produce high-Q, low-loss, high-performance microwave and millimeter-wave balanced filters, but this filter is firstly difficult to process and requires high processing accuracy; secondly, the production cost is relatively expensive; thirdly, this kind of filter The volume of the device is relatively large, and it is difficult to apply it to the design of microwave and millimeter wave integrated circuits. Therefore, there is an urgent need for a microwave and millimeter wave balanced filter with high performance, small size, light weight, high Q value, low loss, low cost, and easy integration, so as to facilitate the design of microwave and millimeter wave integrated circuits.

Contents of the invention

Technical problem: the purpose of this invention is to provide a kind of substrate integrated waveguide balanced filter, this balanced filter has the characteristics of easy integration, relatively low processing cost and simple structure, and is suitable for the design of microwave and millimeter wave integrated circuits; secondly Using this substrate integrated waveguide balanced filter can have better performance; thirdly, compared with the microstrip structure, this balanced filter has higher Q value and lower loss.

Technical solution: The substrate-integrated waveguide balanced filter of the present invention includes a metal patch, a dielectric substrate, and metal through holes; the metal patch is arranged on the dielectric substrate, and the middle part of the metal patch as the main body of the filter is rectangular, with two symmetrical ends It is a "Y"-shaped port, and a row of first metal through holes and a second metal through hole are respectively arranged on both sides of the rectangular middle part of the metal patch along the edge line. Between the two rows of metal through holes, the rectangular metal patch There are also three sections of the third metal through hole, the fourth metal through hole and the fifth metal through hole parallel to the two rows of metal through holes on the center line of the rectangular metal patch. The middle metal through-holes are arranged along the direction from the input end to the first isolation end. The metal middle through-holes are arranged in four rows, of which 4 metal middle large through-holes are located in the middle two rows, and the other 4 metal middle small through-holes are located in the metal middle large through-holes. on both sides. The outer connection lines of the large through hole in the metal form a small rectangle, and the outer connection lines of the small metal through hole form a large rectangle.

The diameter d of the metal through hole is 0.2-0.8 mm, and the distance s is 0.4-1.6 mm. Microstrip line width w=2.5~3.5mm, impedance transformer width tw=6~6.5mm, impedance transformer length tl=14~16mm, directional coupler width a1=9~9.6mm, filter width a2=15.3~ 15.9mm, directional coupler split length d1=25～26.2mm, directional coupler split length l1=11～12.2mm, directional coupler split length 2l2=19～20.2mm, directional coupler split width cutw=3.5～ 4.5mm, filter first through hole diameter vd1=0.8～1.2mm, filter second through hole diameter vd2=2.8～3.2mm, filter third through hole diameter vd3=2.8～3.2mm, filter fourth pass Hole diameter vd4=0.8～1..2mm, filter first resonator length l3=11.9～20.1mm, filter second resonator length l4=13.42～13.62mm, filter third resonator length l5=11.86～ 12.06mm.

The substrate-integrated waveguide balancer utilizes the characteristics of high Q value and low loss of the rectangular metal waveguide. Firstly, the substrate-integrated waveguide and half-mode substrate-integrated waveguide are realized on the basis of the dielectric substrate. These two types of waveguides work with similar transmission characteristics to rectangular metal waveguides; then, a directional coupler is formed by using a half-mode substrate-integrated waveguide; a filter is formed by using a substrate-integrated waveguide, so that the desired signal is passed through directional coupling Sequential output of filter-filter-directional coupler. Due to the function of the directional coupler, the signal in the stop band is not reflected back to the input port but to the isolation end, which can be absorbed by the matching resistor. In the structure of this substrate-integrated waveguide balanced filter, we mainly pay attention to the design of the following points:

1:) All structures are realized by punching a series of metal through-hole arrays on the dielectric substrate, which is conducive to the integration of this substrate-integrated waveguide balanced filter in microwave and millimeter-wave circuit design;

2:) The filtering function of the balanced filter is mainly realized by the filter, so the structure of the substrate integrated filter plays a very important role in the entire substrate integrated waveguide balanced filter;

3:) The function of reducing the reflected signal of the balanced filter is mainly realized by the directional coupler, so the structure of the half-mode substrate integrated waveguide directional coupler plays a very important role in the width of the working frequency band of the entire substrate integrated waveguide balanced filter. role. In this design, a half-mode substrate integrated waveguide structure is used to realize the directional coupler, which reduces the size of the directional coupler.

Beneficial effects: the substrate integrated waveguide balanced filter of the present invention has the following advantages:

1:) This substrate integrated waveguide balanced filter is easy to integrate in the design of microwave and millimeter wave circuits. This is because the balanced filter is completely realized on the dielectric substrate, and the size of the balanced filter can be easily adjusted by using the dielectric constant of the dielectric substrate, so as to better realize the integration with other microwave and millimeter wave circuits ;

2:) can have better performance. This is because its characteristics are similar to those of traditional metal waveguide balanced filters, so it has better performance;

3:) This substrate integrated waveguide balanced filter has higher Q value and lower loss. This is because this structure has similar characteristics to the rectangular metal waveguide, so compared with the microstrip circuit, its Q value is relatively high and the loss is relatively low;

4:) In this design, a half-mode substrate integrated waveguide structure is used to realize the directional coupler, which reduces the size of the structure.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is the actual test result of the present invention.

In Figure 1, there are: metal patch 1, dielectric substrate 2, metal through hole 3, through holes 31 on both sides of the central metal through hole, input end 4, output end 6, first isolation end 5, second isolation end 7, Microstrip line width w, impedance transformer width tw, impedance transformer length tl, directional coupler width a1, filter width a2, directional coupler slit length d1, directional coupler slit length one l1, directional coupler slit length two l2, directional coupler gap width cutw, filter first through hole diameter vd1, filter second through hole diameter vd2, filter third through hole diameter vd3, filter fourth through hole diameter vd4, filter first resonance The length l3 of the filter, the length l4 of the second resonator of the filter, and the length l5 of the third resonator of the filter.

Detailed ways

The substrate-integrated waveguide balanced filter of the present invention includes a metal patch, a dielectric substrate, and a metal through hole; the metal patch is arranged on the dielectric substrate, and the middle part of the metal patch as the main body of the filter is rectangular, and the two ends are symmetrically called "Y ”-shaped ports, a row of first metal through-holes 31 and second metal through-holes 32 are arranged on both sides of the rectangular middle of the metal patch along the sidelines, between the two rows of metal through-holes, the rectangular metal patch There are also three sections of the third metal through hole 33, the fourth metal through hole 34, and the fifth metal through hole 35 parallel to the two rows of metal through holes on the center line, and symmetrically arranged on both sides of the center line of the rectangular metal patch. 4 pairs of intermediate metal vias are arranged along the direction from the input terminal 4 to the first isolation terminal 5. The metal intermediate vias are arranged in four rows, of which 4 large metal intermediate vias are located in the middle two rows, and the other 4 small metal intermediate vias Located on both sides of the large through hole in the middle of the metal. The outer connection lines of the large through hole in the metal form a small rectangle, and the outer connection lines of the small metal through hole form a large rectangle. The diameter d of the metal through hole 3 is 0.2-0.8 mm, and the distance s is 0.4-1.6 mm. Microstrip line width w=2.5~3.5mm, impedance transformer width tw=6~6.5mm, impedance transformer length tl=14~16mm, directional coupler width a1=9~9.6mm, filter width a2=15.3~ 15.9mm, directional coupler split length d1=25～26.2mm, directional coupler split length l1=11～12.2mm, directional coupler split length 2l2=19～20.2mm, directional coupler split width cutw=3.5～ 4.5mm, filter first through hole diameter vd1=0.8～1.2mm, filter second through hole diameter vd2=2.8～3.2mm, filter third through hole diameter vd3=2.8～3.2mm, filter fourth pass Hole diameter vd4=0.8～1..2mm, filter first resonator length l3=11.9～20.1mm, filter second resonator length l4=13.42～13.62mm, filter third resonator length l5=11.86～ 12.06mm.

We have implemented the substrate integrated waveguide balanced filter described above in the X-band Institute. The diameter of the metal through-hole 3 used to form the substrate-integrated waveguide is 0.4m, and the distance between the through-holes 3 is 0.8mm. The dielectric substrate The relative dielectric constant is 2.2, as shown in the accompanying drawing, and the specific structural parameters are as follows:

w=3mm, tw=6.25mm, tl=15mm, a1=9.3mm, d1=25.6mm, l1=11.6mm, l2=19.6mm, cutw=4mm, a2=15.6mm, l3=11.96mm, l4=13.52 mm, l5=11.96mm, vd1=1mm, vd2=3mm, vd3=3mm, vd4=1mm, l3=11.96mm, l4=13.52mm, l5=11.96mm.

Substrate-integrated waveguides and half-mode substrate-integrated waveguides have similar transmission characteristics to rectangular metal waveguides. The substrate integrated waveguide balanced filter we designed makes full use of this characteristic, and uses the half-mode substrate integrated waveguide to realize the directional coupler, and uses the substrate integrated waveguide to realize the filter, thus realizing the substrate integrated waveguide balanced filter performance.

Claims (3)

1. a substrate integrated waveguide balance filter is characterized in that this wave filter comprises metal patch (1), dielectric substrate (2), metal throuth hole (3); Metal throuth hole (3) comprises first metal throuth hole (31), second metal throuth hole (32), the intermetallic metal through hole, metal patch (1) is arranged on the dielectric substrate (2), middle part as the metal patch (1) of filter main body is a rectangle, two is to being called the port of " Y " shape, be respectively equipped with one along the sideline in the both sides of the rectangular central portion of metal patch (1) and ranked first metal throuth hole (31), second metal throuth hole (32), between this two rows metal throuth hole, also be provided with on the center line of metal patch three sections with this two rows metal throuth hole parallel the 3rd metal throuth hole (33), the 4th metal throuth hole (34), five metals belongs to through hole (35), metal throuth holes in the middle of the both sides of the center line of rectangular metal paster also are provided with 4 pairs symmetrically, direction along input end (4) to first isolation end (5) is arranged, the intermetallic metal through hole divides four rows to arrange, two rows in the middle of 4 big intermetallic metal through holes are positioned at, other 4 little intermetallic metal through holes are positioned at the both sides of 4 big intermetallic metal through holes.

2. substrate integrated waveguide balance filter according to claim 1 is characterized in that the aperture d=0.2～0.8mm of metal throuth hole (3), pitch-row s=0.4～1.6mm.

3. substrate integral wave guide filter according to claim 1 is characterized in that the micro belt line width w=2.5～3.5mm on the metal patch (1), impedance transformer width tw=6～6.5mm, impedance transformer length tl=14～16mm, directional coupler width a1=9～9.6mm, filter width a2=15.3～15.9mm, directional coupler fracture length dl=25～26.2mm, directional coupler breach length one l1=11～12.2mm, directional coupler breach length two l2=19～20.2mm, directional coupler slit width cutw=3.5～4.5mm, wave filter first metal throuth hole diameter vd1=0.8～1.2mm, wave filter second metal throuth hole diameter vd2=2.8～3.2mm, wave filter the 3rd metal throuth hole diameter vd3=2.8～3.2mm, wave filter the 4th metal throuth hole diameter vd4=0.8～1..2mm, wave filter first resonator length l3=11.9～20.1mm, wave filter second resonator length l4=13.42～13.62mm, wave filter the 3rd resonator length l5=11.86～12.06mm.

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