CN204905392U - Integrated waveguide filter of dual 14 folding mould substrates - Google Patents

Abstract

The utility model relates to a double folded 1/4 mode substrate integrated waveguide filter. The filter is composed of two DFQMSIW resonant cavities. The stripline is coupled with the DFQMSIW resonator. The filter adopts DFQMSIW resonator, which can reduce the plane size to 1/16 of SIW resonator, and the height is twice that of SIW resonator, which greatly reduces the plane size of resonator, and the filter structure is simple, The processing difficulty is low, and it has strong practicability.

Description

A double folded 1/4 mode substrate integrated waveguide filter

technical field

The utility model belongs to the field of microwave technology, and relates to a double folded 1/4 mode substrate integrated waveguide (Double Folded Quarter Mode Substrate Integrated Waveguide, DFQMSIW) filter based on PCB technology.

Background technique

Substrate Integrated Waveguide (SIW) is a new type of microwave transmission structure that uses metal vias to realize the waveguide field propagation mode on a dielectric substrate. It is a transmission line between a microstrip line and a dielectric filled waveguide. It has the characteristics of small transmission loss and high Q value of traditional waveguide, and has the advantages of small size and low cost of microstrip transmission line, and is easy to integrate with other microwave transmission structures such as microstrip. Microwave devices using SIW as a platform, such as power dividers, directional couplers, filters, oscillators, etc., all have good performance.

When the operating frequency is low, the size of the actual SIW structure and its functional module circuits is relatively large, which affects the integration degree and practical application of the circuit. Therefore, in order to meet the requirements of system miniaturization, many new structures based on SIW technology have appeared, including half-mode substrate integrated waveguide (HMSIW), folded substrate integrated waveguide (FSIW), quarter-mode substrate integrated waveguide ( QMSIW), double folded substrate integrated waveguide (DFSIW) and folded half-mode substrate integrated waveguide (FHMSIW), etc. Combining quarter-mode and double-folded substrate integrated waveguide technology, a double-folded quarter-mode (DFQMSIW) resonator with twice the height of the original SIW resonator and an "L"-shaped groove in the middle metal layer is designed. The planar size of the DFQMSIW resonator is 1/16 of the original SIW resonator.

At present, the design of SIW resonant cavity filters at home and abroad is mainly based on ordinary SIW resonant cavities and HMSIW resonant cavities. At lower frequency bands, SIW or HMSIW resonant cavity filters still have a large volume.

Utility model content

Purpose of the utility model: In order to provide a double-folded 1/4 mode substrate integrated waveguide filter with better effect, the specific purpose can be found in the multiple substantive technical effects in the specific implementation part.

In order to achieve the above object, the utility model takes the following technical solutions:

A double-folded 1/4-mode substrate integrated waveguide filter is characterized in that it includes two dielectric substrates, three metal layers, input ports, and output ports, wherein two dielectric substrates and three metal layers are arranged alternately, each Each dielectric substrate is located between two adjacent metal layers, and each dielectric substrate is provided with two rows of metallized through holes arranged vertically. The input port and output port are located at both ends of the middle metal layer, and the adjacent two resonant The coupling between the cavities is realized through the long slots on the middle metal layer.

The further technical solution of the utility model is that the input port and the output port are respectively coupled with the two closest resonant cavities through microstrip lines.

The utility model adopting the above technical solution has the following beneficial effects relative to the prior art: (1) the utility model filter can reduce the plane size of the filter to that of the common SIW cavity filter due to the adoption of the DFQMSIW resonant cavity 1/16;

(2) The filter of the utility model has the advantages of simple structure, low processing difficulty, easy integration design with other circuits, and the coupling amount can be adjusted through the coupling groove, which has strong practicability.

Description of drawings

In order to further illustrate the utility model, further describe below in conjunction with accompanying drawing:

Fig. 1 is the utility model DFQMSIW resonator model diagram;

Fig. 2 is the stereogram that adopts the DFQMSIW filter structural diagram of the utility model;

Fig. 3 is the plan view that adopts the DFQMSIW filter structural diagram of the present utility model;

Fig. 4 is the S parameter simulation result of DFQMSIW filter.

Detailed ways

Embodiment of the utility model is described below in conjunction with accompanying drawing, and embodiment does not constitute restriction of the utility model:

The principle of the utility model filter is as follows:

Since the SIW works in the main mode TE ₁₀ , the maximum value of the electric field is on the vertical center plane along the propagation direction, so the center plane can be considered as an equivalent magnetic wall, along which the vertical center plane (virtual magnetic wall) can be The SIW is cut into two parts, and each part is a HMSIW. The QMSIW structure is obtained by dividing the HMSIW into two parts along the equivalent magnetic wall, and its field distribution is similar to that of the original SIW. The double-folded SIW is obtained by folding the SIW along the length and width directions at the same time. The height is twice that of the original SIW, and the middle metal layer has an "L"-shaped groove. Combining quarter-mode and double-folded SIW technology, a DFQMSIW resonator is designed, as shown in Figure 1. A plurality of DFQMSIW resonators are arranged horizontally, and adjacent resonators are coupled through slotting, which is easy to realize various forms of filters.

Take the two-cavity DFQMSIW filter as an example below to describe the utility model in detail:

As shown in Figure 3, it is a structural schematic diagram of an embodiment of the DFQMSIW filter of the present utility model. It can be seen from the figure that the filter structure includes an input port, an output port, two dielectric plates, three metal layers, a metallized through hole and a coupling groove, and the input The output ports are respectively located at both ends of the middle metal layer, coupled with the DFQMSIW resonant cavity through a 50Ω microstrip line, and the loaded Q value of the input and output resonant cavity is adjusted by adjusting the coupling position between the microstrip line and the resonant cavity.

The coupling between two adjacent resonators is realized by slotting in the middle metal layer, and the coupling amount is adjusted according to the size of the coupling slot.

Figure 3 shows the designed two-cavity bandpass DFQMSIW filter. A dielectric substrate with a dielectric constant of 2.55 and a height of 1mm is selected to optimize the design parameters. The simulation results of the two-cavity DFQMSIW filter are shown in Figure 4. It can be seen from the results that the center frequency of the filter is 2.9GHz, the relative bandwidth is 20%, the maximum insertion loss in the band is 0.07dB, and the return loss in the working bandwidth is lower than -25dB. The filter volume is 29mm x 12.2mm x 2mm. The resonant cavity is a combination of double folding technology and 1/4 mode technology. The resonant cavity is folded twice on the basis of the 1/4-mode substrate integrated waveguide resonant cavity to form a double-layer structure, and the energy coupling between the upper and lower layers is realized through the "L" gap at the edge of the middle layer. The coupling between the resonators is realized by slotting the intermediate metal layer

The basic principles, main features and advantages of the present utility model have been shown and described above. Those skilled in the art should understand that the utility model is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model There will be various changes and improvements, and these changes and improvements all fall within the scope of the claimed protection.

Claims (2)

1. A double folded 1/4 mode substrate integrated waveguide filter is characterized in that: it comprises two dielectric substrates, three metal layers, input ports, and output ports, wherein two dielectric substrates and three metal layers are alternately arranged , each dielectric substrate is located between two adjacent metal layers, and each dielectric substrate is provided with two rows of vertically arranged metallized through holes, the input port and output port are located at both ends of the middle metal layer, and the adjacent two The coupling between the two resonators is realized through the long slots on the middle metal layer. 2. A double folded 1/4 mode substrate integrated waveguide filter according to claim 1, characterized in that: the input port and the output port are respectively coupled with the two nearest resonant cavities through microstrip lines.