CN203895577U - Band pass filter based on one third equilateral triangle substrate integration waveguide - Google Patents

Abstract

The utility model discloses a band-pass filter based on one-third equilateral triangular substrate integrated waveguide, which comprises six resonant units and two microstrip lines, and the six resonant units are cross-coupled into a hexagonal resonant cavity, two The microstrip lines are respectively connected to the hexagonal resonant cavity as the input end and output end of the bandpass filter. The utility model only adopts one-third of the equilateral triangular cavity, greatly reduces the size of the filter, improves the bandwidth of the passband, and better meets the miniaturization requirements of the modern wireless communication system.

Description

Band-pass filter based on one-third equilateral triangular substrate integrated waveguide

technical field

The utility model belongs to the field of microwave technology, in particular to a band-pass filter based on an integrated waveguide of a one-third equilateral triangle substrate.

Background technique

In modern wireless communication, microwave and millimeter wave communication systems have more and more services, and frequency resources are more tense. Wireless communication technology urgently needs to be developed in the direction of miniaturization, high performance, and low cost. Microwave filters are used to separate signals and are one of the key parts in today's wireless communication systems.

In recent years, substrate-integrated waveguide technology has been proposed. Due to the characteristics of high-quality factors, low insertion loss, high integration, and high-power capacity of substrate-integrated waveguide technology, microwave components have been developed more broadly. Among substrate integrated waveguide filters, rectangular and circular cavity filters have been greatly developed, while triangular filters have been less studied. How to reduce the size of the triangular filter, increase the passband bandwidth of the filter, and better meet the miniaturization requirements of modern wireless communication systems has become an increasingly problem to be solved in this field.

Utility model content

In order to solve the problems of the above-mentioned background technology, the utility model aims to be based on one-third equilateral triangle

A waveguide-integrated band-pass filter with a shaped substrate reduces the size of the filter and improves the pass-band bandwidth of the filter.

In order to realize above-mentioned technical purpose, the technical scheme of the utility model is:

A band-pass filter based on one-third equilateral triangular substrate integrated waveguide, the band-pass filter includes six resonant units and two microstrip lines, and each resonant unit includes the top metal layer, The dielectric substrate and the underlying metal layer, the shape of the top metal layer, the dielectric substrate and the underlying metal layer are mutually congruent planar quadrilaterals, and the planar quadrangle includes a first side, a second side, a third side and a fourth side. side, the angle between the first side and the second side is 60°, the third side is perpendicular to the second side, the fourth side is perpendicular to the first side, the angle between the third side and the fourth side is 120°, and in Metallized through holes are uniformly arranged along the first side and the second side of the dielectric substrate. Among the four sides of the resonance unit, two sides of the metallized through holes are used as electric walls, and the other two sides are used as magnetic walls. Two resonant units are cross-coupled into a hexagonal resonant cavity, and the electric walls of adjacent resonant units are coupled together through inductive windows to form the aforementioned hexagonal resonant cavity, and the two microstrip lines are respectively connected to the hexagonal resonant cavity, As the input and output of the bandpass filter.

Wherein, adjacent magnetic walls of adjacent resonant units in the above-mentioned hexagonal resonant cavity are all on the same plane.

Wherein, the above-mentioned hexagonal resonant cavity is symmetrical about the central horizontal axis and the central vertical axis of the bandpass filter.

Wherein, the impedances of the above two microstrip lines are both 50 ohms. The two microstrip lines are symmetrical about the central horizontal axis and the central vertical axis of the bandpass filter.

Wherein, two groups of defect structures are etched on the underlying metal layer of the hexagonal resonant cavity. Each set of defective ground structures includes two parallel slotting lines, and each slotting line is in the shape of a dumbbell. The structures of the two groups of defects are symmetrical about the central horizontal axis and the central vertical axis of the bandpass filter.

The beneficial effect brought by adopting the above-mentioned technical scheme:

(1) Compared with the traditional equilateral triangular cavity filter, the utility model only uses one-third of the equilateral triangular cavity, which greatly reduces the size of the filter and improves the passband bandwidth to better meet the needs of modern wireless communications. System miniaturization requirements. The utility model adopts the substrate integrated waveguide technology, has a very compact structure, reduces processing difficulty and processing cost, and has wide application prospects in modern wireless communication systems;

(2) The input and output of the utility model adopts a 50-ohm microstrip line structure, and no matching structure is needed. The underlying metal layer is slotted using a defect-based structure technology to achieve the purpose of suppressing the generation of parasitic bands.

Description of drawings

Fig. 1 is a schematic diagram of a method for cutting an equilateral triangular cavity into one third of an equilateral triangular cavity.

Fig. 2 is a schematic diagram of one third of an equilateral triangular cavity.

Fig. 3 is a schematic three-dimensional dissection diagram of one third of an equilateral triangular cavity.

Fig. 4 is a structural schematic diagram of a bandpass filter based on one-third equilateral triangular substrate integrated waveguide of the present invention.

FIG. 5 is a schematic diagram of an equivalent structure of the bandpass filter shown in FIG. 4 in simulation or in processing.

FIG. 6 is a schematic three-dimensional dissection diagram of the equivalent structure of the filter shown in FIG. 5 .

FIG. 7 is a schematic diagram of a defective ground structure.

Fig. 8 is an S-parameter simulation waveform diagram of the present invention.

Explanation of the reference numerals in the drawings: 1 is the top metal layer, 2 is the dielectric substrate, 3 is the metallized through hole, 4 is the bottom metal layer, and 5 is the defect structure.

Detailed ways

The technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings.

In the above technical solution, the resonant unit is substantially divided into equilateral triangular resonant cavities. As shown in Figure 1, the schematic diagram of the method for cutting an equilateral triangular cavity into one third of an equilateral triangular cavity, the equilateral triangular resonator consists of a top metal layer 1 and a dielectric substrate 2 (using Rogers 5880 dielectric) from top to bottom. plate, with a dielectric constant of 2.2 and a thickness of 0.8mm) and the underlying metal layer 4, and metallized through holes 3 are evenly distributed along its three sides on the dielectric substrate. The equilateral triangular resonant cavity is divided into three identical resonant units along the vertical line segments from the center to the three sides. The shape of the resulting resonance unit is shown in Figure 2, and the structure of the resonance unit is shown in Figure 3.

As shown in Figure 4, the structure diagram of a bandpass filter based on one-third equilateral triangular substrate integrated waveguide, the bandpass filter contains six resonant units and two microstrip lines, and each resonant unit contains a top metal layer, a bottom metal layer, and four sides, in which two sides with metallized through holes 3 are used as electric walls, and the other two sides are used as magnetic walls. Six resonant units are cross-coupled into a hexagonal resonant cavity, and adjacent The electric walls of the unit are coupled together through the inductive window to form a hexagonal resonant cavity, and the two microstrip lines are respectively connected to the hexagonal resonant cavity as the input end and output end of the bandpass filter.

In simulation and actual processing, for convenience, the filter structure shown in Figure 4 can be equivalent to the structure shown in Figure 5 .

In this embodiment, the adjacent magnetic walls of the adjacent resonant units in the hexagonal resonant cavity are all on the same plane, so as to achieve the maximum magnetic coupling. The hexagonal resonant cavity is symmetrical about the central horizontal axis and the central vertical axis of the bandpass filter. The impedance of both microstrip lines is 50 ohms. The two microstrip lines are symmetrical about the central horizontal axis and the central vertical axis of the bandpass filter.

As shown in FIG. 6 , a three-dimensional schematic diagram of an equivalent structure of a filter, a structure 5 with two groups of defects is etched on the underlying metal layer of the hexagonal resonant cavity. Each group of defective ground structures 5 includes two parallel slotting lines, and each slotting line is in the shape of a dumbbell, as shown in FIG. 7 . The two groups of defective ground structures 5 are symmetrical about the central horizontal axis and the central vertical axis of the bandpass filter.

As shown in Figure 8, the S-parameter simulation waveform diagram of the utility model, the abscissa is frequency (unit: gigahertz), and the ordinate is S-parameter (unit: decibel), wherein, the solid line represents the relationship between the electromagnetic wave reflection coefficient and frequency, The dotted line represents the relationship between the electromagnetic wave transmission coefficient and the frequency. It can be seen from the figure that the center frequency is 7.53GHz, the 3dB bandwidth is 5.64GHz~10.06GHz, the in-band insertion loss is about 2dB, and the return loss is greater than 15dB, indicating that the filter has good passband performance.

The above embodiments are only to illustrate the technical ideas of the present invention, and can not limit the protection scope of the present invention with this. All technical ideas proposed in accordance with the present invention, any changes made on the basis of technical solutions, all fall within the protection scope of the present invention. Inside.

Claims (8)

1. the band pass filter based on 1/3rd equilateral triangle substrate integral waveguides, it is characterized in that: described band pass filter comprises six resonant elements and two microstrip lines, each resonant element comprises top layer metallic layer from top to bottom successively, dielectric substrate and bottom metal layer, described top layer metallic layer, the plane quadrilateral that is shaped as mutual congruence of dielectric substrate and bottom metal layer, described plane quadrilateral comprises first side, Second Edge, the 3rd limit and the 4th limit, the angle of first side and Second Edge is 60 °, the 3rd limit is perpendicular to Second Edge, the 4th limit is perpendicular to first side, the angle on the 3rd limit and the 4th limit is 120 °, and on dielectric substrate along its first side and the Second Edge plated-through hole of evenly arranging, in four sides of resonant element, there are two sides of plated-through hole as electric wall, another two sides are as magnetic wall, six resonant element cross-couplings are a hexagon resonant cavity, the electric wall of adjacent resonant element is coupled by perceptual window, form aforementioned hexagonal shape resonant cavity, described two microstrip lines connect respectively hexagon resonant cavity, input and output as this band pass filter.

2. the band pass filter based on 1/3rd equilateral triangle substrate integral waveguides according to claim 1, is characterized in that: in described hexagon resonant cavity, the adjacent magnetic wall of adjacent resonant element all at grade.

3. according to the band pass filter based on 1/3rd equilateral triangle substrate integral waveguides described in claim 1 or 2, it is characterized in that: described hexagon resonant cavity is symmetrical about central, transverse axis and the center longitudinal axis of described band pass filter.

4. the band pass filter based on 1/3rd equilateral triangle substrate integral waveguides according to claim 1, is characterized in that: the impedance of described two microstrip lines is 50 ohm.

5. according to the band pass filter based on 1/3rd equilateral triangle substrate integral waveguides described in claim 1 or 2 or 4, it is characterized in that: described two microstrip lines are symmetrical about central, transverse axis and the center longitudinal axis of described band pass filter.

6. the band pass filter based on 1/3rd equilateral triangle substrate integral waveguides according to claim 1, is characterized in that: on the bottom metal layer of described hexagon resonant cavity, be etched with two groups of defect ground structures.

7. the band pass filter based on 1/3rd equilateral triangle substrate integral waveguides according to claim 6, is characterized in that: described every group of defect ground structure comprises two parallel slotted lines, every slotted line be shaped as dumbbell shape.

8. according to the band pass filter based on 1/3rd equilateral triangle substrate integral waveguides described in claim 6 or 7, it is characterized in that: described two groups of defect ground structures are symmetrical about central, transverse axis and the center longitudinal axis of described band pass filter.