WO2018171231A1

WO2018171231A1 - Dual-band band-pass filter based on open loads and short-circuit loads

Info

Publication number: WO2018171231A1
Application number: PCT/CN2017/111487
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: CN206673067U

Abstract

The present utility model provides a dual-band band-pass filter based on open loads and short-circuit loads, comprising two first microstrip lines, an input end, an output end, and a second microstrip line which are formed on the upper surface of a dielectric slab by means of etching. Two ends of each first microstrip line are respectively provided with an open load and a short-circuit load; the middle parts of the two first microstrip lines are connected by means of the second microstrip line; the input end is connected to one of the first microstrip lines, and the output end is connected to the other one; two ends of the second microstrip lines are respectively communicated with the input end and the output end, and are located at a same horizontal line, which serves as a first central axis; a second central axis is vertical to the first central axis; the end of the short-circuit load is provided with a short-circuit metal post, which is connected to a ground metal layer provided on the lower surface of the dielectric slab. The dual-band band-pass filter in the present utility model applies a good inhibitory effect on out-of-band signals, achieves high selectivity, introduces less noise, and avoids interference to a radio frequency front end.

Description

Dual band pass filter based on open circuit load and short circuit load

[0001] The present invention relates to the field of radio frequency microwave communication technologies, and in particular, to a dual band pass filter based on a circuit load and a short circuit 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 dual band pass filter based on a crotch load and a short circuit load, which aims to solve the technical problem of low selectivity of the band pass filter in the prior art.

Problem solution

Technical solution

[0004] In order to achieve the above object, the present invention provides a dual band pass filter based on a circuit load and a short circuit load, including a dielectric plate, two first microstrip lines etched on the surface of the dielectric plate, and an input. a terminal, an output end and a second microstrip line, and a ground metal layer disposed on a lower surface of the dielectric plate, the dual band pass filter being vertically symmetrical about the first central axis and bilaterally symmetric about the second central axis, wherein:

[0005] The two ends of each of the first microstrip lines are respectively provided with a circuit load and a short circuit load, and the middle portions of the two first microstrip lines are connected by the second microstrip line;

[0006] one end of the bypass load and one end of the short-circuit load are disposed at opposite ends of the first microstrip line at mutually orthogonal angles and are connected to each other;

[0007] one end of the input end is disposed in a middle of one of the first microstrip lines and the other end of the input end extends to a long edge of the dielectric plate; [0008] one end of the output end is disposed in the middle of the other first microstrip line and the other end of the output end extends to the other long edge of the dielectric plate;

[0009] Both ends of the second microstrip line are respectively connected to the input end and the output end and are located on the same horizontal line, the horizontal line is a first central axis, and the second central axis is perpendicular to the first central axis;

[0010] The end of the short-circuit load is provided with a short-circuited metal post that penetrates from the upper surface of the dielectric plate to the lower surface of the dielectric plate and is connected to the ground metal layer disposed on the lower surface of the dielectric plate.

[0011] Preferably, the ground metal layer is a copper-clad metal layer laid on a lower surface of the dielectric plate.

[0012] Preferably, the two first microstrip lines are disposed parallel to each other on the upper surface of the dielectric plate and are bilaterally symmetric with respect to the second central axis, and the two ends of the second microstrip line are vertically connected to the two A microstrip between the lines.

[0013] Preferably, the number of one end of the bypass load and the number of short-circuit loads are four, and one end load and one short-circuit load are respectively disposed at two ends of each first microstrip line.

[0014] Preferably, the first microstrip line, the second microstrip line, the crotch load, the short-circuit load, the input end, and the output end are all metal strips of a strip structure.

[0015] Preferably, the length of the first microstrip line is 46.66 mm, the width is W, and 1.221^^ the length of the second microstrip line is L. =9.78mm, width W. =1.35mm, the length of the input end and the output end are both L=14.4mm and the width is W=1.66mm.

[0016] Preferably, the length of the short-circuit load is! ^二^!^!!, the width is W ₂ = 3mm, the length of the bypass load is 1^ ₃ = 111^^ The width is W ₃ = 1.7mm.

[0017] Preferably, the short-circuited metal pillar has a column shape.

Advantageous effects of the invention

Beneficial effect

[0018] Compared with the prior art, the dual-band pass filter based on the open circuit load and the short circuit load of the present invention loads four open circuit loads and four short circuit loads on two microstrip lines, and is adjusted by The length and width of the circuit load and the short-circuit load can form a transmission zero point in a specific frequency band, so that the original microstrip line has filtering performance, thereby having high band-pass selectivity, and can have a good suppression effect on the out-of-band signal. It has high selectivity and introduces less noise to avoid interference with the RF front end. The dual band pass filter of the present invention is connected to the conventional microstrip line through two first microstrip lines with respect to the existing band pass filter, and four microcircuit loads are connected, and the microstrip is changed by The length and width of the line can make The dual-band pass filter achieves a good matching effect in the operating frequency band.

Brief description of the drawing

DRAWINGS

1 is a schematic diagram of an upper surface structure of a dual band pass filter based on a bypass load and a short circuit load according to the present invention;

2 is a schematic view showing a lower surface structure of a dual band pass filter based on a bypass load and a short circuit load according to the present invention;

3 is a schematic diagram of S-parameter results of the simulation of the electromagnetic simulation software of the dual-band pass filter based on the open-circuit load and the short-circuit load of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

BEST MODE FOR CARRYING OUT THE INVENTION

[0022] 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 schematic diagram showing the upper surface structure of a dual-band pass filter based on a bypass load and a short-circuit load according to the present invention. In this embodiment, the dual-band pass filter based on the circuit load and the short-circuit load includes a dielectric plate 1, two first microstrip lines 10 etched on the upper surface of the dielectric plate 1, an input end P1, and an output end. P2 and a second microstrip line 11, and a ground metal layer 14 disposed on the lower surface of the dielectric plate (refer to FIG. 2). The two ends of each of the first microstrip lines 10 are respectively provided with a bypass load 12 and a short-circuit load 13. The middle portions of the two first microstrip lines 10 are connected by the second microstrip line 11, and one end of the input end P1 is disposed at One of the first microstrip lines 10 and the other end of the input end P1 extends to one long edge of the dielectric plate 1, and one end of the output end P2 is disposed at the middle of the other first microstrip line 10 and the output end The other end of P2 extends to the other long edge of the PC B board 2. A short-circuited metal post 130 is disposed at the end of each of the short-circuit loads 13, and the short-circuit metal post 130 may have a columnar shape such as a cylindrical shape or a long cylindrical shape. The dielectric plate 1 is a P CB plate, 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.

[0024] The two ends of the second microstrip line 11 are respectively connected to the input end PI and the output end P2 and are located on the same horizontal line ab. In this embodiment, the horizontal line ab is used as the first central axis ab. The dual-band pass filter based on the ramp load and the short-circuit load of the present invention is vertically symmetrical about the first central axis ab, and about the second central axis The cd is bilaterally symmetrical, and the first central axis ab and the second central axis cd are perpendicular to each other. The two first microstrip lines 10 are disposed in parallel with each other on the upper surface of the dielectric plate 1 and are symmetric with respect to the second central axis cd, and the second microstrip line 11 and the two first microstrip lines 10 are perpendicularly connected to each other. One end of the bypass load 12 and one end of the short-circuit load 13 are disposed at both ends of each of the first microstrip lines 10 at an arbitrary angle of intersection and communicate with each other. In the present embodiment, one end of the bypass load 12 and one end of the short-circuit load 13 are disposed at opposite ends of each of the first microstrip lines 10 at mutually orthogonal angles and communicate with each other.

[0025] It should be noted that the long edge of the dielectric plate 1 defined by the present embodiment refers to the two edges of the dielectric plate 1 parallel to the second central axis cd. The two first microstrip lines 10 are spaced apart by a distance equal to the length of the second microstrip line 11. When one end of the bypass load 12 and one end of the short-circuit load 13 are connected to each other at both ends of the first microstrip line 10 in a mutually orthogonal manner, the distance between the bypass load 12 and the short-circuit load 13 is smaller than the two first microstrips. The separation distance between the lines 10. Since both ends of the two first microstrip lines 10 are provided with a bypass load 12 and a short-circuit load 13, the dual-band pass filter of the present invention has four open circuit loads 12 and four short-circuit loads. 13. The four-way load 12 and the four short-circuit loads 13 enable the dual-band pass filter of the present invention to have two stop bands in any working frequency band, so that the dual-band pass filter of the present invention has dual frequency characteristics. , with high band pass selectivity.

In the present embodiment, the first microstrip line 10, the second microstrip line 11, the open circuit load 12, the short-circuit load 13, the input end P1, and the output end P2 are all metal strips of a strip structure. The dual band pass filter based on the ramp load and the short circuit load of the present invention is connected to the four band load 12 and the four short circuit loads 13 through the two first microstrip lines 12 with respect to the existing band pass filter. On the second microstrip line 11, and by changing the length and width of the microstrip line, the dual band pass filter based on the open circuit load and the short circuit load of the present invention can achieve a good matching effect in the working frequency band.

[0027] The present invention takes the dual frequency characteristic of the operating frequency band in the range of 2.61 GHz to 3.23 GHz and in the range of 4.75 GHz to 5.02 GHz as an example, and the first microstrip disposed on the upper surface of the dielectric board 1 by way of a specific embodiment. The length and width of the line 10, the second microstrip line 11, the bypass load 12, the short-circuit load 13, the input terminal P1, and the output terminal P2. In the present embodiment, the length of the first microstrip line 10 is 22.5 mm + 1.66 mm = 46.66 mm, and the width of the first microstrip line 10 is W, = 1.221 ^ ^ The length of the second microstrip line 11 is! ^.

= 9.78 mm, the width of the second microstrip line 11 is W. =1.35mm. The lengths of the input terminal PI and the output terminal P2 are both L=14.4 mm, and the widths of the input terminal PI and the output terminal P2 are both W=1.66 mm. The road load 1 The length of 2 is 1^ ₃ =111^^ The width of the load 12 is \¥ ₃ =1.71^ _3⁄4 The length of the short-circuit load 13 is 1^ ₂ = l lmm, and the width of the short-circuit load 13 is \¥ ₂ =31^ ^ It should be noted that the thickness of the metal copper plate disposed on the PCB board is generally um level, so the present invention does not apply to the first microstrip line 10, the second microstrip line 11, the winding load 12, the short-circuit load 13, The thickness of the metal copper of the input terminal P1 and the output terminal P2 is limited, and does not affect the characteristics of the dual-band pass filter based on the bypass load and the short-circuit load of the present invention.

Referring to FIG. 2, FIG. 2 is a schematic diagram showing the structure of the lower surface of the dual band pass filter based on the open circuit load and the short circuit load of the present invention. In the present embodiment, the short-circuited metal post 130 at the end of each short-circuit load 13 penetrates from the upper surface of the dielectric plate 1 to the lower surface of the dielectric plate 1, and is connected to the ground metal layer 14 of the lower surface of the dielectric plate 1, the ground The metal layer 14 is a copper-clad metal layer laid on the lower surface of the dielectric plate 1.

[0029] The dual-band pass filter based on the ramp load and the short-circuit load according to the present invention is designed by the above structure, by loading four open circuit loads 12 and four short-circuit loads 13 on the conventional microstrip line, Adjusting the length and width of the circuit load 12 and the short-circuit load 13 can form a transmission zero point in a specific operating frequency band, so that the original microstrip line has filtering performance, can have a good suppression effect on the out-of-band signal, and has a high passband signal. Selectivity, introduce less noise, and avoid interference with the RF front end.

Referring to FIG. 3, FIG. 3 is a schematic diagram of S-parameter results simulated by the electromagnetic simulation software of the dual-band pass filter based on the open-circuit load and the short-circuit load of the present invention. In general, in general, bandpass filters allow different frequency band signals to enter the system, filtering out of the out-of-band signals or noise. As can be seen from FIG. 3, the reflection coefficient (IS11I) of the dual-band pass filter based on the ramp load and the short-circuit load of the present invention is in the range of 2.61 GHz to 3.23 GHz and in the range of 4.75 GHz to 5.02 GHz. Below 10 dB, the dual-band pass filter can operate in the range of 2.61 GHz to 3.23 GHz and in the range of 4.75 GHz to 5.02 GHz, so that the dual frequency characteristic can be realized. At 2.13GHz, the transmission characteristics (IS21I) of the dual-band pass filter of the present invention can reach -35.8dB, at 4.13GHz, IS21I can reach SJ-50.6dB, and at 5.27GHz, IS21I can reach SJ- 34dB, so the dual band pass filter of the present invention has high selectivity. It can be seen that the dual-band pass filter based on the ramp load and the short-circuit load of the present invention can have a good suppression effect on the out-of-band signal, has high selectivity to the passband signal, introduces less noise, and avoids the RF front end. This causes interference and therefore greatly improves the performance of the microwave circuit.

[0031] The dual-band pass filter based on the coast load and the short-circuit load of the present invention loads four turn-on loads 12 and four short-circuit loads 13 on two microstrip lines, by adjusting the turn-on load 12 and Short-circuit load 13 The length and width can form a transmission zero in a specific frequency band, so that the original microstrip line has filtering performance, thereby having a higher band pass selectivity. The dual band pass filter of the present invention connects four turnkey loads 12 and four short circuit loads 13 to the conventional microstrip line through two first microstrip lines 12 with respect to the existing band pass filter, and By changing the length and width of the microstrip line, the dual band pass filter of the present invention can achieve a good matching effect in the working frequency band.

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.

Industrial applicability

[0033] Compared with the prior art, the dual-band pass filter based on the coast load and the short-circuit load of the present invention loads four turn-on loads and four short-circuit loads on two microstrip lines, and adjusts The length and width of the circuit load and the short-circuit load can form a transmission zero point in a specific frequency band, so that the original microstrip line has filtering performance, thereby having high band-pass selectivity, and can have a good suppression effect on the out-of-band signal. It has high selectivity and introduces less noise to avoid interference with the RF front end. The dual band pass filter of the present invention is connected to the conventional microstrip line through two first microstrip lines with respect to the existing band pass filter, and four microcircuit loads are connected, and the microstrip is changed by The length and width of the line enable the dual band pass filter to achieve a good match in the operating band.

Claims

Claim

[Claim 1] A dual band pass filter based on a crowbar load and a short circuit load, comprising a dielectric plate, two first microstrip lines etched on a surface of the dielectric plate, an input end, an output end, and a second micro a strip line and a ground metal layer disposed on a lower surface of the dielectric sheet, wherein the dual band pass filter is vertically symmetrical about a first central axis and symmetrical about a second central axis, wherein: each of the first microstrips The two ends of the line are respectively provided with a circuit load and a short circuit load, and the middle portions of the two first microstrip lines are connected by the second microstrip line; one end of the circuit load and one end of the short circuit load are arranged at mutually orthogonal angles And communicating with each other at both ends of the first microstrip line; one end of the input end is disposed at a middle portion of one of the first microstrip lines and the other end of the input end extends to a long edge of the dielectric plate; the output One end of the end is disposed in the middle of the other first microstrip line and the other end of the output end extends to the other long edge of the dielectric plate; the two ends of the second microstrip line are respectively connected to the input end The output ends are connected to each other and are on the same horizontal line, the horizontal line is a first central axis, and the second central axis is perpendicular to the first central axis; the short-circuited metal is provided with a short-circuited metal post, and the short-circuited metal post is from the dielectric plate The upper surface penetrates to the lower surface of the dielectric plate and is connected to the ground metal layer disposed on the lower surface of the dielectric plate.

[Claim 2] The dual-band pass filter based on the load and short circuit load according to claim 1, wherein the ground metal layer is a copper-clad metal layer laid on a lower surface of the dielectric plate

[Claim 3] The dual-band pass filter based on the load-carrying load and the short-circuit load according to claim 1, wherein the two first microstrip lines are disposed in parallel with each other on an upper surface of the dielectric plate and Regarding the second central axis, the two ends of the second microstrip line are vertically connected between the two first microstrip lines.

[Claim 4] The dual-band pass filter based on the open-circuit load and the short-circuit load according to claim 1, wherein the number of one end of the open circuit load and the short-circuit load are four, each A two-way load and a short-circuit load are respectively disposed at both ends of the first microstrip line.

[Claim 5] The dual-band pass filter based on the load and short circuit load according to claim 1, wherein the first microstrip line, the second microstrip line, the off-line load, and the short-circuit load , The input end and the output end are metal copper sheets of a strip structure.

The dual-band pass filter based on the load and short circuit load according to claim 5, wherein the first microstrip line has a length of 46.66 mm and a width of W, = 1.22 mm, and the second The length of the microstrip line is L. =9.78mm, width is \¥.

=1.35mm, the length of the input end and the output end are both L=14.4mm and the width is \¥= 1.66mm.

The dual-band pass filter based on the open-circuit load and the short-circuit load according to claim 6, wherein the short-circuit load has a length of ₂ = 111^^ and a width of W ₂ = 3 mm, and the load of the open circuit The length is 1^ ₃ = 111^^ and the width is W ₃ = 1.7 mm.

The dual-band pass filter based on a crotch load and a short-circuit load according to claim 1, wherein the short-circuited metal post has a columnar shape.