WO2018171230A1

WO2018171230A1 - Band-pass filter based on ring resonator and double-stub open loads

Info

Publication number: WO2018171230A1
Application number: PCT/CN2017/111486
Authority: WO
Inventors: 曲美君; 邓力; 李书芳; 张贯京; 葛新科; 高伟明; 张红治
Original assignee: 深圳市景程信息科技有限公司
Priority date: 2017-03-18
Filing date: 2017-11-17
Publication date: 2018-09-27
Also published as: CN206602160U

Abstract

The present utility model provides a band-pass filter based on a ring resonator and double-stub open loads, comprising a dielectric slab, and a ground metal layer provided on the lower surface of the dielectric slab, as well as an input end, an output end, an input microstrip line, an output microstrip line, a first coupling line, a second coupling line, a ring resonator, a first double-stub open load, a second double-stub open load, a first double-stub impedance matcher, and a second double-stub impedance matcher which are formed on the upper surface of the dielectric slab by means of etching. The band-pass filter is symmetrical about a central axis of the dielectric slab. According to the present utility model, the band-pass filter is symmetrical about a central axis; the ring resonator is built by the middlemost four microstrip lines, and a double-stub open load is separately loaded at the input end and the output end, to bring a good band-pass matching effect for the band-pass filter within a working band, apply a good inhibitory effect on out-of-band signals, achieve high selectivity on band-pass signals, introduce less noise, and avoid interference to a radio frequency front end.

Description

Band-pass filter based on ring resonator and double-branch node load

[0001] The present invention relates to the field of radio frequency microwave communication technologies, and in particular, to a band pass filter based on a ring resonator and a double branch node load.

Background technique

[0002] As a very important device in the RF front-end, the filter can filter out-of-band noise and improve the sensitivity of the circuit system. A microstrip filter is a device used to separate microwave signals of different frequencies. Its main function is to suppress unwanted signals so that they cannot pass through the filter and only pass the desired signal. In microwave circuit systems, the performance of the filter has a large impact on the performance of the circuit system. Due to the diversity of communication bands in modern communication systems, the selectivity of prior art bandpass filters is often insufficient to meet the diversity of communication bands and affect the performance of the entire communication system.

technical problem

[0003] It is an object of the present invention to provide a band pass filter based on a ring resonator and a double-branch node load, which aims to solve the technical problem of low selectivity of the conventional band pass filter.

Problem solution

Technical solution

[0004] In order to achieve the above object, the present invention provides a band pass filter based on a ring resonator and a double branch load, including a dielectric plate, a ground metal layer disposed on a lower surface of the dielectric plate, and an etched medium. Input, output, input microstrip, output microstrip, first coupled line, second coupled line, ring resonator, first double branch load, second double branch load, a first double branch impedance matcher and a second double branch impedance matcher, wherein:

[0005] one end of the input microstrip line is connected to the input end, and the other end of the input microstrip line is connected to the first double branch impedance matching device;

[0006] one end of the output microstrip line is connected to the output end, and the other end of the output microstrip line is connected to a second double-branch section impedance matcher;

[0007] The first coupling line includes a first coupled microstrip line and a second coupled microstrip line, and one of the first coupled microstrip lines The end is orthogonally connected to one end of the second coupled microstrip line;

[0008] the second coupling line includes a third coupled microstrip line and a fourth coupled microstrip line, and one end of the third coupled microstrip line is orthogonally connected to one end of the fourth coupled microstrip line;

[0009] The ring resonator is a rectangular resonator composed of four resonant microstrip lines, and the ring resonator is disposed between the second coupled microstrip line and the fourth coupled microstrip line;

[0010] the first dual branch node load includes a first load microstrip line and a second load microstrip line, and the second double branch node load includes a third load microstrip line and a fourth load microstrip line, One end of a load microstrip line is connected to the input end, the other end of the first load microstrip line is connected to one end of the second load microstrip line, one end of the third load microstrip line is connected to the output end, and the third load microstrip The other end of the line is connected to one end of the fourth load microstrip line;

[0011] the first coupled microstrip line is spaced apart from the first load microstrip line, and the third coupled microstrip line is spaced apart from the third load microstrip line, and the first coupled microstrip line is The spacing between the first load microstrip lines is equal to the spacing between the third coupled microstrip line and the third loaded microstrip line.

[0012] Preferably, the ring resonator comprises a first resonant microstrip line, a second resonant microstrip line, a third resonant microstrip line and a fourth resonant microstrip line, the first resonant microstrip line and the second coupling The spacing between the microstrip lines is equal to the spacing between the third resonant microstrip line and the fourth coupled microstrip line.

[0013] Preferably, a spacing between the input microstrip line and the first coupled microstrip line is equal to a spacing between the output microstrip line and the third coupled microstrip line.

[0014] Preferably, the first double-branch impedance matching device includes a first impedance matching line and a second impedance matching line, and the second double-branch impedance matching device includes a third impedance matching line and a fourth impedance matching line. Wherein: [0015] one end of the first impedance matching line is orthogonally connected to one end of the input microstrip line, and the other end of the first impedance matching line is connected to one end of the second impedance matching line;

[0016] One end of the third impedance matching line is orthogonally connected to one end of the output microstrip line, and the other end of the third impedance matching line is connected to one end of the fourth impedance matching line.

[0017] Preferably, the length of the first line and the third impedance matching lines are 1 ^ ₂ = 23.41 ^^ width are ₂ = 0.27mm W, the second impedance matching line and the fourth line The length is L _{1 =} 21.64 ηιιη. The width is W, = 2.830^1.

[0018] Preferably, the lengths of the first resonant microstrip line and the third resonant microstrip line are both C _u = 23.48 mm, The lengths of the second resonant microstrip line and the fourth resonant microstrip line are both 1^=23.081^^ the first resonant microstrip line, the second resonant microstrip line, the third resonant microstrip line, and the fourth resonant microstrip line The width is W ₅ = 0.25 mm.

[0019] Preferably, the length of the input end and the output end are both L. =15mm, width is W. =1.66mm, the lengths of the input microstrip line and the output microstrip line are both Cl ₂ =23.8 mm and the width is Cw ₂ =0.14 mm; the lengths of the first coupled microstrip line and the third coupled microstrip line Both are CI ₂ = 23.8 mm, and the lengths of the second coupled microstrip line and the fourth coupled microstrip line are both C1, = 23.481^^ the first coupled microstrip line, the second coupled microstrip line, and the third The width of the coupled microstrip line and the fourth coupled microstrip line is Cw ^Ο. Πη η^

[0020] Preferably, the lengths of the first load microstrip line and the third load microstrip line are L ₄ = 22.3 mm, and the width is \¥ ₄ =1.421^^ the second load microstrip line and the fourth load The length of the microstrip line is 1^=22.671^^ and the width is W ₃ =0.915 mm.

[0021] Preferably, the spacing between the first resonant microstrip line and the second coupled microstrip line, and the spacing between the third resonant microstrip line and the fourth coupled microstrip line are both Cs _{1 =} 0.48ιηιη The spacing between the input microstrip line and the first coupled microstrip line, and the spacing between the output microstrip line and the third coupled microstrip line are both Cs ₂ =0.465 mm

Advantageous effects of the invention

Beneficial effect

[0022] Compared with the prior art, the band pass filter based on the ring resonator and the double branch node load is symmetric about the central axis ab of the dielectric plate, wherein the middlemost four microstrip lines can be configured. A ring resonator, and a double branch node load is respectively loaded at the input terminal P1 and the output terminal P2, which can provide a good band pass matching effect in the working frequency band of the band pass filter of the present invention. In addition, the bandpass filter based on the ring resonator and the double-branch node load can have a good suppression effect on the out-of-band signal, high selectivity to the passband signal, and introduce less noise, avoiding The RF front end causes interference.

Brief description of the drawing

DRAWINGS

1 is a schematic plan view showing a preferred embodiment of a band pass filter based on a ring resonator and a double branch node load according to the present invention.

2 is a preferred embodiment of a bandpass filter based on a ring resonator and a double-branch node load in accordance with the present invention [0024] Schematic diagram of the structure size.

3 is a schematic diagram of S-parameter results of a band-pass filter based on a ring resonator and a double-branched load on the electromagnetic simulation software of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are illustrative of the present invention, and the present invention is not limited to the following embodiments.

Referring to FIG. 1, FIG. 1 is a plan view showing a preferred embodiment of a preferred embodiment of a band pass filter based on a ring resonator and a double-branch load. In this embodiment, the band pass filter includes a dielectric plate 1, an input terminal P1 etched on the upper surface of the dielectric plate 1, an output terminal P2, an input microstrip line 11, an output microstrip line 12, and a first coupling line. 13. A second coupling line 14, a ring resonator 15, a first double branch circuit load 16, a second double branch circuit load 17, a first double branch impedance matcher 18, a second double link impedance matcher 19, and A ground metal layer (not shown in Fig. 1) provided on the lower surface of the dielectric plate 1. The dielectric plate 1 is a PCB board, and the specific plate type is Roger.

RO4350B, which has a relative dielectric constant of 3.66 and a plate thickness of 0.762 mm. The ground metal layer is a copper-clad metal layer laid on the lower surface of the dielectric plate 1.

[0028] One end of the input microstrip line 11 is connected to the input end P1, and the other end of the input microstrip line 11 is connected to the first double branch impedance matching device 18; one end of the output microstrip line 12 is connected to the output end P2, The other end of the output microstrip line 12 is connected to the second double branch impedance matcher 19. The first dual branch impedance matcher 18 includes a first impedance matching line 181 and a second impedance matching line 182, and the second double branch impedance matching unit 18 includes a third impedance matching line 191 and a fourth impedance matching line 192. One end of the first impedance matching line 181 is orthogonally connected to one end of the input microstrip line 11 to form an L shape, that is, the first impedance matching line 181 and the input microstrip line 11 are perpendicularly connected to each other, and the other end of the first impedance matching line 181 is connected. To one end of the second impedance matching line 182. One end of the third impedance matching line 1 91 is orthogonally connected to one end of the output microstrip line 12 to form an L shape, that is, the third impedance matching line 191 and the output microstrip line 12 are perpendicularly connected to each other, and the other end of the third impedance matching line 191 is connected. Connected to one end of the fourth impedance matching line 192.

[0029] The first coupling line 13 includes a first coupled microstrip line 131 and a second coupled microstrip line 132. One end of the first coupled microstrip line 131 is orthogonally connected to one end of the second coupled microstrip line 132. L-shaped, ie, the first coupled microstrip The line 131 and the second coupled microstrip line 132 are perpendicularly connected to each other. The second coupling line 14 includes a third coupled microstrip line 141 and a fourth coupled microstrip line 142. One end of the third coupled microstrip line 141 is orthogonally connected to one end of the fourth coupled microstrip line 142 to form an L shape. The third coupled microstrip line 141 and the fourth coupled microstrip line 142 are perpendicularly connected to each other. The input microstrip line 11 is spaced apart from the first coupled microstrip line 131, and the output microstrip line 12 is spaced apart from the third coupled microstrip line 141. The input microstrip line 11 and the first coupled microstrip line are spaced apart. The spacing between 131 is equal to the spacing between the output microstrip line 12 and the third coupled microstrip line 141.

[0030] The ring resonator 15 is disposed between the second coupled microstrip line 132 and the fourth coupled microstrip line 142, and the ring resonator 15 is formed by a rectangle of four resonant microstrip lines, that is, the first resonant microstrip line 151. A rectangular resonator composed of a second resonant microstrip line 152, a third resonant microstrip line 153, and a fourth resonant microstrip line 154. The first resonant microstrip line 151 of the ring resonator 15 is spaced apart from the second coupled microstrip line 132, and the third resonant microstrip line 153 of the ring resonator 15 is spaced apart from the fourth coupled microstrip line 142. The spacing between the first resonant microstrip line 151 and the second coupled microstrip line 132 is equal to the spacing between the third resonant microstrip line 153 and the fourth coupled microstrip line 142.

[0031] The first dual branch circuit load 16 includes a first load microstrip line 161 and a second load microstrip line 162, and the second double branch circuit load 17 includes a third load microstrip line 171 and a fourth load microstrip Line 172. One end of the first load microstrip line 161 is connected to the input terminal P1, and the other end of the first load microstrip line 161 is connected to one end of the second load microstrip line 162. One end of the third load microstrip line 171 is connected to the output terminal P2, and the other end of the third load microstrip line 171 is connected to one end of the fourth load microstrip line 172. The connection of the first load microstrip line 161 to the input terminal P1 does not overlap with the connection of the input microstrip line 11 to the input terminal P1, such that the first coupled microstrip line 131 is spaced from the first load microstrip line 161 There is a gap to prevent mutual interference of signal energy between the two. The junction of the third load microstrip line 171 connected to the output terminal P2 and the output microstrip line 12 connected to the output terminal P1 do not overlap, such that the third coupled microstrip line 141 is spaced from the third load microstrip line 171 There is a gap to prevent mutual interference of signal energy between the two. In this embodiment, a spacing between the first coupled microstrip line 131 and the first load microstrip line 161 is equal to a spacing between the third coupled microstrip line 141 and the third loaded microstrip line 171, the spacing Preferably, it is 2 mm to 5 mm to avoid mutual interference of signal energy between the two.

[0032] It should be noted that the band pass filter based on the ring resonator and the double-branched load of the present invention is bilaterally symmetric with respect to the central axis ab of the band pass filter. The present invention is based on a ring resonator and The bandpass filter of the double-branch section is compared with the existing bandpass filter, wherein the middlemost four microstrip lines can form a ring resonator, and a double-branch node is loaded at the input terminal P1 and the output terminal P2, respectively. The road load can provide a good band pass matching effect in the operating frequency band of the band pass filter of the present invention. In addition, the band pass filter designed by the above structure can have a good suppression effect on the out-of-band signal, has high selectivity to the passband signal, introduces less noise, and avoids interference to the RF front end.

Referring to FIG. 2, FIG. 2 is a schematic diagram showing the structure of a preferred embodiment of a bandpass filter based on a ring resonator and a double-branched load. The utility model etches the input end P1 on the upper surface of the dielectric plate 1, the output terminal P2, the input microstrip line 11, the output microstrip line 12, the first coupling line 13, the second coupling line 14, the ring resonator 15, the first A pair of branching road load 16, a second double branch circuit load 17, a first double branch impedance matching device 18 and a second double branch impedance matching device 19 are all metal copper pieces, and the input microstrip line, The output microstrip line, the load microstrip line, the coupled microstrip line, and the resonant microstrip line are all metal strip microstrip lines with a strip structure, just to distinguish each microstrip line by a different name. The utility model takes the working frequency band in the range of 1.82 GHz to 2.19 GHz as an example, and illustrates the length of the structural size of the preferred embodiment of the band-pass filter based on the ring resonator and the double-branched-bridge load of the present invention by way of a specific embodiment. And width.

[0034] In this embodiment, the lengths of the input terminal P1 and the output terminal P2 are both L. =15mm, width is \¥.

= 1.66mm. The lengths of the input microstrip line 11 and the output microstrip line 12 are both CI ₂ = 23.8 mm, and the width is Cw.

[0035] The lengths of the first coupled microstrip line 131 and the third coupled microstrip line 141 are both CI ₂ = 23.8 mm, and the lengths of the second coupled microstrip line 132 and the fourth coupled microstrip line 142 are both C1, = 23.481 The width of the first coupled microstrip line 131, the second coupled microstrip line 132, the third coupled microstrip line 141, and the fourth coupled microstrip line 142 is Cw, =0.17 mm.

[0036] The lengths of the first resonant microstrip line 151 and the third resonant microstrip line 153 of the ring resonator 15 are both CI,

= 23.48 mm, the lengths of the second resonant microstrip line 152 and the fourth resonant microstrip line 154 are both L ₅ = 23.08 mm. A first microstrip line resonator 151, a second resonant microstrip line 152, the third resonator microstrip line, microstrip line and a fourth resonator 154 are a width W ₅ = 0.25mm.

[0037] The lengths of the first load microstrip line 161 and the third load microstrip line 171 are 1^ ₄ =22.31^^, and the width is W ₄ = 1.42 mm; the lengths of the second load microstrip line 162 and the fourth load microstrip line 172 are both L ₃ = 22.67 mm and the width is W ₃ = 0.915 mm.

[0038] The lengths of the first impedance matching line 181 and the third impedance matching line 191 are 1^ ₂ = 23.41^^, and the width is \¥ ₂

=0.27 mm; the lengths of the second impedance matching line 182 and the fourth impedance matching line 192 are both L _{1 =} 21.64 ηιιη. The width is W, = 2.830^1.

a spacing between the first resonant microstrip line 151 and the second coupled microstrip line 132, a spacing Cs between the third resonant microstrip line 153 and the fourth coupled microstrip line 142,

=0.48mm. The spacing between the input microstrip line 11 and the first coupled microstrip line 131, and the spacing between the output microstrip line 12 and the third coupled microstrip line 141 are both Cs ₂ =0.465 mm.

[0040] It should be noted that the thickness of the metal copper plate disposed on the PCB board is generally um, so the present invention does not apply to the input terminal P1, the output terminal P2, the input microstrip line 11, the output microstrip line 12, and the first a coupling line 13, a second coupling line 14, a ring resonator 15, a first double branch circuit load 16, a second double branch circuit load 17, a first double branch impedance matcher 18, and a second double branch impedance matching The thickness of the metal copper of the device 19 is limited, and does not affect the characteristics of the bandpass filter based on the ring resonator and the double-branched load of the present invention.

Referring to FIG. 3, FIG. 3 is a schematic diagram of S-parameter results of the bandpass filter of the present invention based on the ring resonator and the double-branched-bridge load through the electromagnetic simulation software. In general, bandpass filters allow different band signals to enter the system, filtering out-of-band signals or noise. As can be seen from FIG. 3, it can be seen that the reflection coefficient (IS11I) of the band pass filter of the present invention is below -10 dB in the range of 1.82 GHz to 2.19 GHz, indicating that the band pass filter can operate at 1.82 GHz. Within 2.19 GHz, a relative bandwidth of 18.5% can be achieved. At 1.1 GHz, the transmission characteristic (IS21I) of the band pass filter of the present invention can reach -33dB, and at 2.7G Hz, the IS21I can reach -72dB, so the band pass filter of the present invention has a high Selectivity. It can be seen that the band-pass filter based on the ring resonator and the double-branch node load can have a good suppression effect on the out-of-band signal, has high selectivity to the pass band signal, introduces less noise, and avoids the radio frequency. The front end causes interference, which can greatly improve the performance of the microwave circuit.

The above is only a preferred embodiment of the present invention, and thus does not limit the scope of the patent of the present invention, and the equivalent structure or equivalent process transformation using the specification and the drawings of the present invention, or directly or indirectly In other related technical fields, the same is included in the scope of patent protection of the present invention. Inside.

Industrial applicability

Compared with the prior art, the band-pass filter based on the ring resonator and the double-branch node load is symmetric about the central axis ab of the dielectric plate, wherein the four middlemost microstrip lines can form a ring resonance. And a double-branch node load is loaded on the input terminal P1 and the output terminal P2 respectively, which can provide a good band pass matching effect in the working frequency band of the band pass filter of the present invention. In addition, the bandpass filter based on the ring resonator and the double-branch node load can have a good suppression effect on the out-of-band signal, high selectivity to the passband signal, and introduce less noise, avoiding The RF front end causes interference.

Claims

Claim

[Claim 1] A band pass filter based on a ring resonator and a double-branch node load, comprising a dielectric plate and a ground metal layer disposed on a lower surface of the dielectric plate, wherein the band pass filter further includes an engraved The input end of the surface of the dielectric plate, the output end, the input microstrip line, the output microstrip line, the first coupling line, the second coupling line, the ring resonator, the first double branch node load, and the second double branch node a road load, a first double branch impedance matcher, and a second double branch impedance matcher, wherein: one end of the input microstrip line is connected to the input end, and the other end of the input microstrip line is connected to the first double link An impedance matching device; one end of the output microstrip line is connected to the output end, and the other end of the output microstrip line is connected to a second double branch impedance matching device; the first coupling line includes a first coupled microstrip line And a second coupled microstrip line, one end of the first coupled microstrip line is orthogonally connected to one end of the second coupled microstrip line; the second coupled line includes a third coupled microstrip line and a fourth coupled microstrip line, One end of the third coupled microstrip line is orthogonally connected to one end of the fourth coupled microstrip line; the ring resonator is a rectangular resonator composed of four resonant microstrip lines, and the ring resonator is disposed in the second coupled micro Between the strip line and the fourth coupled microstrip line; the first dual branch node load comprises a first load microstrip line and a second load microstrip line, and the second double branch node load comprises a third load microstrip line And a fourth load microstrip line, one end of the first load microstrip line is connected to the input end, the other end of the first load microstrip line is connected to one end of the second load microstrip line, and one end of the third load microstrip line is connected To the output end, the other end of the third load microstrip line is connected to one end of the fourth load microstrip line; the first coupled microstrip line is spaced apart from the first load microstrip line, and the third coupled microstrip line The spacing between the third coupled microstrip line and the first loaded microstrip line is equal to the spacing between the third coupled microstrip line and the third loaded microstrip line.

[Claim 2] The ring resonator based on a ring resonator and a double branch node load according to claim 1, wherein the ring resonator includes a first resonant microstrip line and a second resonant microstrip a line, a third resonant microstrip line, and a fourth resonant microstrip line, wherein a spacing between the first resonant microstrip line and the second coupled microstrip line is equal to between the third resonant microstrip line and the fourth coupled microstrip line spacing.

[Claim 3] Band-pass filtering based on ring resonator and double-branch node load according to claim 2. The spacing between the input microstrip line and the first coupled microstrip line is equal to the spacing between the output microstrip line and the third coupled microstrip line.

[Claim 4] The ring resonator based on the ring resonator and the double branch node load according to claim 3, wherein the first double branch impedance matcher comprises a first impedance matching line and a second An impedance matching line, the second double-branch impedance matching device includes a third impedance matching line and a fourth impedance matching line, wherein: one end of the first impedance matching line is orthogonally connected to one end of the input microstrip line, first The other end of the impedance matching line is connected to one end of the second impedance matching line; one end of the third impedance matching line is orthogonally connected to one end of the output microstrip line, and the other end of the third impedance matching line is connected to the fourth impedance matching One end of the line.

[Claim 5] The band-pass filter based on the ring resonator and the double-branched-bridge load according to claim 4, wherein the length of the first impedance matching line and the third impedance matching line is L 2 =23.4mm, width is \¥ ₂ =0.27mm, the length of the second impedance matching line and the fourth impedance matching line are both L ₁₌ 21.64mm and the width is W ₁₌ 2.83! ^^

[Claim 6] The ring resonator based on the ring resonator and the double branch node load according to claim 5, wherein the lengths of the first resonant microstrip line and the third resonant microstrip line are both For CI, = 2 A^mm, the lengths of the second resonant microstrip line and the fourth resonant microstrip line are both L ₅ = 23.08 mm, the first resonant microstrip line, the second resonant microstrip line, and the third resonant micro Both the strip line and the fourth resonant microstrip line have a width of W ₅ = 0.25 mm.

[Claim 7] The band-pass filter based on the ring resonator and the double-branch node load according to claim 6, wherein the length of the input end and the output end are both L. =15mm, width is W. =1.66mm, the lengths of the input microstrip line and the output microstrip line are both CI ₂ = 23.8 mm and the width are Cw ₂ = 0.14 mm; the first coupled microstrip line and the third coupled microstrip line length are ₂ = 23.8mm CI, coupled to said second microstrip line and the fourth length are coupled microstrip lines C1, = 23.481 ^^ said first coupling microstrip lines, coupled to the second microstrip line, a first The widths of the three coupled microstrip lines and the fourth coupled microstrip line are both Cw fO. nmn^

[Claim 8] The band-pass filter based on a ring resonator and a double-branch node load according to claim 7, wherein the lengths of the first load microstrip line and the third load microstrip line are both L ₄ = 22.3mm, width is \¥ ₄ = 1.42mm, second load microstrip line and fourth load micro The length of the strip line is L ₃ = 22.67 mm and the width is W ₃ = 0.915 mm.

[Claim 9] The ring resonator based on the ring resonator and the double branch node load according to claim 8, wherein the first resonant microstrip line and the second coupled microstrip line are between The pitch, the spacing between the third resonant microstrip line and the fourth coupled microstrip line are both Cs _{1 =} 0.48 η η, the spacing between the input microstrip line and the first coupled microstrip line, and the output microstrip line The spacing between the third coupled microstrip line and the third coupled microstrip line is Cs ₂ =0.465 mm.