CN220400873U - A miniaturized quarter-mode square SIW resonant cavity and bandpass filter - Google Patents

Abstract

The utility model provides a miniaturized quarter-mode square SIW resonant cavity and a band-pass filter. The miniaturized quarter-mode square SIW resonant cavity comprises: a quarter-die square SIW cavity, wherein a metalized through hole is formed at one vertex of the quarter-die square SIW cavity to form an electric wall, a periodic metal through hole array is arranged along the edges of two adjacent sides where the other vertex which is diagonal to the vertex provided with the metal through hole is located, and a slit which is in an L shape overall is etched at one side of the periodic through hole array to form a magnetic wall; the quarter-mode square SIW cavity is obtained by cutting the square SIW resonant cavity along equivalent magnetic walls which are perpendicular to each other.

Description

A miniaturized quarter-mode square SIW resonant cavity and bandpass filter

Technical field

The utility model relates to the technical fields of electromagnetic fields and microwaves, and in particular to a miniaturized quarter-mode square SIW resonant cavity and a band-pass filter.

Background technique

With the rapid development of the communications industry, the low-frequency bands of the radio spectrum are approaching saturation. There is an increasing demand for the exploration of high-frequency bands such as microwaves and millimeter waves. A focus on satellite radar and 5G communication technologies is also on On the development and utilization of microwave and millimeter waves. The miniaturization and high integration of mobile devices have also put forward increasingly 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 technology. Microstrip has the advantages of easy integration, easy processing and design, and low cost. However, in the high frequency range, the loss of microstrip is too large due to its open structure. In line with the requirements of engineering design indicators, as early as the early 21st century, Professor Wu Ke from the University of Montreal in Canada and Professor Hong Wei from Southeast University proposed substrate integration based on studying the integration issues between microstrip planar circuits and non-planar circuits. The concept of Substrate Integrated Waveguide (SIW). SIW greatly reduces the loss of microwave devices by adding a periodic metal through hole array. However, unlike the large volume of traditional rectangular waveguides, SIW technology has a high Q value and low loss, simple structure, easy integration and miniaturization. Subsequently, the technologies of half-modeSubstrate Integrated Waveguide (HMSIW) and quarter-modeSubstrate Integrated Waveguide (QMSIW) were proposed. While retaining the original advantages, they further reduced the Reduce the size of microwave devices.

The filter is a frequency-selective device that plays an indispensable role in the entire radio frequency circuit. Currently, there are many studies on single-mode filters at home and abroad. In contrast, research on multi-mode filters is relatively unpopular, and multi-mode filters are less popular. 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 utility model provides a miniaturized quarter-mode square SIW resonant cavity and a band-pass filter.

On the one hand, the utility model provides a miniaturized quarter-mode square SIW resonant cavity, including: 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 electric wall, and a periodic array of metal through holes is provided along the two adjacent edges where the other vertex is diagonal to the vertex where the metal through hole is located. An overall "L"-shaped gap is etched on one side of the sexual through-hole array to form a magnetic wall; wherein, the quarter-mode square SIW cavity is obtained by cutting a square SIW resonant cavity along mutually perpendicular equivalent magnetic walls. .

Further, the "L"-shaped gap is located on one side of the periodic metal through hole array close to the center of the quarter-mode square SIW cavity.

On the other hand, the present invention provides a miniaturized quarter-mode square SIW bandpass filter, which includes the above-mentioned miniaturized quarter-mode square SIW resonant cavity, with the square SIW resonant cavity having The center is the center of the circle, and a first periodic metal through hole array is provided along the circumferential direction; four second periodic metal through hole arrays are provided outside the first periodic metal through hole array and along the two diagonal directions of the square SIW resonant cavity. Periodic metal through hole array; microstrip feed lines are provided on two adjacent sides of the vertex where the metal through hole is located.

Beneficial effects of this utility model:

(1) This utility model provides a miniaturized quarter-mode square SIW resonant cavity and a new miniaturized quarter-mode square SIW three-mode bandpass filter. Compared with the traditional filter designed based on SIW , this utility model 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, achieving simplification and miniaturization of the filter design. .

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

Description of the drawings

Figure 1 is a schematic structural diagram of a miniaturized quarter-mode square SIW resonant cavity provided by an embodiment of the present invention;

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

Figure 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 utility model more clear, the technical solutions in the embodiments of the present utility model will be clearly described below in conjunction with the accompanying drawings in the embodiments of the utility model. Obviously, the described embodiments are Some embodiments of the present invention are not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present utility model.

Example 1

As shown in Figure 1, an embodiment of the present invention provides a quarter-mode square SIW resonant cavity, including a quarter-mode square SIW cavity, in which the quarter-mode square SIW cavity A metal through hole is provided at one vertex to form an electric wall, and periodic metal through hole arrays are provided along two adjacent edges where the other vertex is diagonal to the vertex 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 resonance cut along mutually perpendicular equivalent magnetic walls. Cavity is obtained.

The "L"-shaped gap is located on one side of the periodic metal via array close to the center of the quarter-mode square SIW cavity.

Among them, metal through holes 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 resonant cavity along the vertical and horizontal equivalent magnetic walls, its area is reduced by 75% compared to the traditional square SIW resonant cavity, and the structure is more compact. Suitable for research and design of miniaturized filters.

Example 2

As shown in Figure 2, an embodiment of the present invention provides a miniaturized quarter-mode square SIW bandpass filter, including a miniaturized quarter-mode square SIW resonant cavity in the above embodiment, so 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; outside the first periodic metal through hole array and along the two diagonal directions of the square SIW resonant cavity Four second periodic metal through-hole arrays are provided; microstrip feed lines are provided on each of the two adjacent sides where the vertex where the metal through-hole is located is located.

A single-cavity three-mode filter is realized by arranging a first periodic metal through-hole array and a second periodic metal through-hole array in a quarter-mode square SIW resonant cavity to excite three modes in the resonant cavity. A single-cavity multi-mode filter excites multiple modes of resonance on a resonator, which can greatly reduce the size of the filter. It is of great significance to the research of miniaturized filters. On the basis of QMSIW technology, a 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 achieved. The relative bandwidth of 25% improves the signal transmission capability of the filter.

Example 3

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

The full-mode square SIW resonant cavity is cut along the vertical and horizontal equivalent magnetic walls, so that the volume of the full-mode square SIW resonant cavity is reduced by 75%, forming a quarter-mode square SIW cavity, etched along the four quarters of the surrounding A rectangular gap 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 there are periodic metal through holes arranged on the diagonal of the square SIW resonant cavity. To achieve three modes of excitation control.

Among them, as shown in Figure 2, L is the overall length of the second periodic metal through-hole array (also the distance from the metal through-holes arranged on the diagonal line in the cavity to the edge intersection), Le represents the microstrip feeder and the setting The distance between the vertices with metal through holes, W ₀ is the width of the microstrip feeder, W ₁ is the width of the quarter rectangular gap etched along the perimeter, r ₀ is each metal through hole in the metal via array The radius of r ₁ represents the radius of the metal through hole located at the vertex, and r ₂ represents the radius of the circle formed by the first periodic metal through hole array. By adjusting the size of L and r ₂ , the frequencies of the three modes can be controlled and the three modes can be excited. The width W ₀ of the microstrip feeder can be roughly obtained from the thickness, dielectric constant and resonance frequency of the dielectric substrate. By adjusting the parameter W ₀ Allows for better 50Ω impedance matching.

As an implementation method, the single-cavity three-mode bandpass filter uses a single-layer Taconic RF-5 dielectric substrate with a thickness h=0.787mm, a relative dielectric constant ε _r =2.2, and a loss tangent tanδ=0.0009.

Figure 3 is the S-parameter diagram of the three-mode bandpass filter. The implementation indicators of this three-mode bandpass filter are: the 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 . Among them, the size parameters of the three-mode bandpass filter are shown in Table 1:

Table 1 Three-mode QMSIW bandpass filter size parameters (unit: mm)

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

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

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit it; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some of the technical features can be equivalently replaced; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the spirit of the technical solutions of the various embodiments of the present invention. and scope.

Claims (3)

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