CN116315531A - A Miniaturized Quarter-mode Square SIW Resonator and Bandpass Filter - Google Patents

Abstract

The invention provides a miniaturized quarter-mode square SIW resonant cavity and a band-pass filter. The miniaturized quarter-mode square SIW resonant cavity includes: a quarter-mode square SIW cavity, and a metal through hole is arranged at one of the vertices of the quarter-mode square SIW cavity to form The electric wall is provided with a periodic metal through hole array along the two adjacent edges where the other vertex that is diagonal to the vertex provided with the metal through hole is located, and is etched on one side of the periodic through hole array There is an overall "L"-shaped gap to form a magnetic wall; wherein, the quarter-mode square SIW cavity is obtained by cutting a square SIW resonant cavity along equivalent magnetic walls that are perpendicular to each other.

Description

A Miniaturized Quarter-mode Square SIW Resonator and Bandpass Filter

technical field

The invention relates to the technical fields of electromagnetic field and microwave, in particular to a miniaturized quarter-mode square SIW resonant cavity and a bandpass filter.

Background technique

With the rapid development of the communication industry, the low-frequency band of the radio spectrum is approaching saturation, and there is an increasing demand for the exploration of high-frequency bands such as microwave and millimeter waves, and a focus on satellite radar and 5G communication technology is also placed on the Development and utilization of microwave and millimeter waves. The miniaturization and high integration of mobile devices also put forward higher and higher requirements for the size of RF and microwave devices. The miniaturization and high power capacity of RF and microwave devices are also crucial to various engineering design indicators.

At present, the design and application of most circuit systems use microstrip line technology. Microstrip line has the advantages of easy integration, easy processing design, and low cost. However, in the high frequency range, the loss of microstrip line is too large due to the open structure. In line with the requirements of engineering design indicators, as early as the early 21st century, Professor Wu Ke of the University of Montreal in Canada and Professor Hong Wei of Southeast University and others proposed the substrate integration based on the integration of microstrip planar circuits and non-planar circuits. The concept of Substrate Integrated Waveguide (SIW), SIW greatly reduces the loss of microwave devices by adding periodic metal through-hole arrays, but unlike the large volume of traditional rectangular waveguides, SIW technology has high Q value and low loss, simple structure, easy integration and miniaturization. Later, the Half-mode Substrate Integrated Waveguide (HMSIW) and Quarter-mode Substrate Integrated Waveguide (QMSIW) technologies were proposed, which further reduced the The size of the microwave device is reduced.

The filter is a frequency selection device, which plays an indispensable role in the entire radio frequency circuit. At present, there are many studies on single-mode filters at home and abroad. In contrast, the research on multi-mode filters is relatively unpopular, and multi-mode Filters are of great significance in the fields of filter miniaturization, ultra-wideband and multi-band design.

Contents of the invention

In order to further realize the miniaturization of the filter, the invention provides a miniaturized quarter-mode square SIW resonant cavity and a band-pass filter.

In one aspect, the present invention provides a miniaturized quarter-mode square SIW resonant cavity, comprising: a quarter-mode square SIW cavity, at one of the vertices of the quarter-mode square SIW cavity A metal through hole is provided to form an electrical wall, and a periodic array of metal through holes is provided along the two adjacent edges where the other vertex that is diagonal to the vertex provided with the metal through hole is located. One side of the through-hole array is etched with an overall "L"-shaped gap to form a magnetic wall; wherein, the quarter-mode square SIW cavity is obtained by cutting a square SIW resonant cavity along equivalent magnetic walls that are perpendicular to each other.

Further, the "L"-shaped slit is located on a side of the periodic metal via array close to the center of the quarter mold square SIW cavity.

On the other hand, the present invention provides a miniaturized quarter-mode square SIW bandpass filter, including a miniaturized quarter-mode square SIW resonator as described above, with the center of the square SIW resonator is the center of the circle, and a first periodic array of metal vias is provided along the circumferential direction; four second periods are provided outside the first periodic array of metal vias and along the two diagonals of the square SIW resonant cavity An array of permanent metal through holes; microstrip feeders are respectively arranged on the two adjacent sides where the vertex with the metal through holes is located.

Beneficial effects of the present invention:

(1) The present invention provides a miniaturized quarter-mode square SIW resonant cavity and a novel miniaturized quarter-mode square SIW three-mode bandpass filter, compared to traditional filters designed based on SIW, The invention uses a quarter-mode square SIW resonant cavity to reduce the volume of the filter, and can excite three modes by arranging different periodic metal through holes in the center of the cavity, thereby realizing simplification and miniaturization of the filter design.

(2) the miniaturized quarter-mode square SIW three-mode bandpass filter of the present invention can realize the relative bandwidth of 25%, and realize the return loss better than-20dB under the relative bandwidth of 25%, harmonic The frequency is at 4.4GHz.

Description of drawings

FIG. 1 is a schematic structural diagram of a miniaturized quarter-mode square SIW resonator provided by an embodiment of the present invention;

Fig. 2 is a schematic structural view of a third-order quarter-mode square SIW three-mode bandpass filter provided by an embodiment of the present invention;

FIG. 3 is an S-parameter diagram of a third-order quarter-mode square SIW three-mode bandpass filter provided by an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the present invention Examples, not all examples. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

As shown in Figure 1, the embodiment of the present invention provides a quarter-mode square SIW resonant cavity, including a quarter-mode square SIW cavity, and one of the quarter-mode square SIW cavities A metal through hole is provided at the vertex to form an electric wall, and a periodic metal through hole array is provided along the two adjacent edges where the other vertex is diagonal to the vertex provided with the metal through hole. One side of the periodic through-hole array is etched with an overall "L"-shaped gap to form a magnetic wall; wherein, the quarter-mode square SIW cavity is a square SIW resonant cavity cut along equivalent magnetic walls that are perpendicular to each other get.

The "L"-shaped slit is located on a side of the periodic metal via array close to the center of the quarter-mold square SIW cavity.

Among them, metal vias can not only prevent electromagnetic leakage, but also improve the quality factor of the resonant cavity. Since the quarter-mode square SIW cavity is formed by cutting the square SIW resonator along the vertical and horizontal equivalent magnetic walls, its area is reduced by 75% compared with the traditional square SIW resonator, and the structure is relatively compact. Suitable for research design of miniaturized filters.

Example 2

As shown in FIG. 2, an embodiment of the present invention provides a miniaturized quarter-mode square SIW bandpass filter, including a miniaturized quarter-mode square SIW resonator in the above-mentioned embodiment, with the The center of the square SIW resonant cavity is the center of the circle, and a first periodic metal through hole array is arranged along the circumferential direction; it is arranged outside the first periodic metal through hole array and along the two diagonal directions of the square SIW resonant cavity There are four second periodic metal through-hole arrays; microstrip feeders are respectively arranged on two adjacent sides where the vertex with the metal through-hole is located.

By arranging the first periodic metal through hole array and the second periodic metal through hole array in the quarter-mode square SIW resonant cavity to excite three modes in the resonant cavity, a single-cavity three-mode filter is realized. The single-cavity multi-mode filter excites multiple modes of resonance on one resonator, which can greatly reduce the size of the filter, which is of great significance for the research of miniaturized filters. On the basis of QMSIW technology, the single-cavity multi-mode structure is realized. The size of the filter can be further reduced. Due to the instability of multiple mode frequencies, three-mode resonance is realized, and the relative bandwidth of 25% improves the transmission capability of the filter for signals.

Example 3

On the basis of the above-mentioned embodiments, the single-cavity three-mode filter provided by the embodiment of the present invention includes three layers in total, the top layer and the bottom layer are metal plates made of copper, and the middle layer is a dielectric layer made of Taconic RF-5.

Cut the full-mode square SIW resonator along the vertical and horizontal equivalent magnetic walls, so that the volume of the full-mode square SIW resonator is reduced by 75%, forming a quarter-mode square SIW cavity, and etching a quarter of the surrounding area A rectangular slit is equivalent to the magnetic wall of the resonant cavity. Periodically arranged metal through holes are arranged in the cavity. The periodic metal through holes are arranged in a circle and the periodic metal through holes are arranged on the diagonal of the square SIW resonant cavity. To achieve three modes of excitation regulation.

Wherein, as shown in FIG. 2, L is the overall length of the second periodic metal via array (also the distance from the metal vias arranged on the diagonal in the cavity to the intersection point of the adjacent edge), and Le represents the microstrip feeder and the setting The distance between vertices with metal vias, W ₀ is the width of the microstrip feeder line, W ₁ is the width of the quarter-rectangular slot etched along the surrounding, r ₀ is each metal via in the metal via array , r ₁ represents the radius of the metal via located at the apex, and r ₂ represents the radius of the circle formed by the first periodic metal via array. By adjusting the size of L and _r2 , the frequencies of the three modes can be regulated, and the three modes can be excited; the width W ₀ of the microstrip feeder can be roughly obtained from the thickness of the dielectric substrate, the dielectric constant and the resonant frequency. By adjusting the parameter W ₀ Better 50Ω impedance matching is possible.

As a possible implementation, the single-cavity triple-mode bandpass filter adopts a single-layer Taconic RF-5 dielectric substrate with thickness h=0.787mm, relative permittivity ε _r =2.2, and loss tangent tanδ=0.0009.

Fig. 3 is the S parameter diagram of the three-mode bandpass filter. The realization index of this three-mode bandpass filter is: the working frequency is at 4.4GHz, the 3dB relative bandwidth is 25%, the in-band insertion loss of the filter is -1.5dB, and the return loss in the passband is better than -20dB. Among them, the size parameters of the three-mode bandpass filter are shown in Table 1:

Table 1 Dimensional parameters of the three-mode QMSIW bandpass filter (unit: mm)

parameter name L Le W ₀ W ₁ r ₀ value 10 17 0.8 0.35 0.35 parameter name r ₁ r ₂ \ \ \ value 0.4 4 \ \ \

Due to the quarter-mode structure, the miniaturization of the filter is realized, and the plane size of the band-pass filter without the microstrip feeder is 30mm*30mm. According to the S-parameter results, the filter operating frequency is at 4.4GHz, the relative bandwidth at -3dB is 25%, the in-band insertion loss of the filter is -1.5dB, and the return loss in the passband is better than -20dB. Therefore, the three-mode QMSIW band-pass filter proposed by the embodiment of the present invention realizes a single-cavity three-mode structure and meets corresponding design indicators, and has a good application prospect in wireless communication systems.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (3)

1. A miniaturized quarter-mode square SIW cavity, characterized in that it comprises: a quarter-mode square SIW cavity, at one of the vertices of the quarter-mode square SIW cavity A metal through hole is provided to form an electrical wall, and a periodic array of metal through holes is provided along the two adjacent edges where the other vertex that is diagonal to the vertex provided with the metal through hole is located. One side of the through-hole array is etched with an overall "L"-shaped gap to form a magnetic wall; wherein, the quarter-mode square SIW cavity is obtained by cutting a square SIW resonant cavity along equivalent magnetic walls that are perpendicular to each other. 2. A miniaturized quarter-mode square SIW resonator according to claim 1, wherein the "L"-shaped slit is located near the quarter of the periodic metal via array. One side of the center of the square SIW cavity. 3. A miniaturized quarter-mode square SIW bandpass filter is characterized in that it comprises a miniaturized quarter-mode square SIW resonator as claimed in claim 1 or 2, with the square The center of the SIW resonator is the center of the circle, and a first periodic array of metal through holes is arranged along the circumferential direction; outside the first periodic array of metal through holes and along the two diagonal directions of the square SIW resonator, there are Four second periodic metal through hole arrays; microstrip feeders are respectively arranged on two adjacent sides where the vertices provided with the metal through holes are located.

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