CN209948009U - Reflection-free band-pass filter and radio frequency communication equipment - Google Patents

Abstract

The utility model discloses a non-reflection band-pass filter and radio frequency communication equipment. The filter comprises a dielectric plate, the lower layer of the dielectric plate is provided with a floor, and the upper layer of the dielectric plate is provided with a first feeder, a second feeder, a first a band-rejection path, a second band-rejection path and a band-pass path; the first feeder is connected to the second feeder through the band-pass path, and the first feeder and the first band-rejection path are respectively mirror-symmetrical with the second feeder and the second band-rejection path; The first band-stop path is connected to the first feeder, and the end of the first band-stop path is loaded with a first resistor, the second band-stop path is connected to the second feeder, and the end of the second band-stop path is loaded with a second resistor, The first band-stop via, the second band-stop via, the first resistor and the second resistor are all connected to the ground through metal through holes. The utility model has the advantages of simple structure, low insertion loss, convenient manufacturing, low cost, etc., and good absorption of out-of-band reflected signals, which greatly improves the linearity of the circuit and simplifies the complexity of the circuit.

Description

Non-reflection bandpass filter and radio frequency communication equipment

technical field

The utility model relates to a filter, in particular to a non-reflection bandpass filter and radio frequency communication equipment, belonging to the technical field of communication.

Background technique

A filter is a frequency selection device, and any device capable of signal processing can be called a filter. In modern telecommunications equipment and various control systems, filters are widely used; among all electronic components, as the electronic components with the most use and the most complex technology, the quality of the filter directly determines the quality of the product. The research and production of equipment has always been attached great importance by various countries.

With the continuous development of communication technology, the performance requirements for passive devices continue to increase, and high performance, low cost, and miniaturization have become the focus of passive device design. The circuit designed by the traditional filter is to reflect the undesired signal back to the signal source through the stop band, which will have a huge impact on the communication performance of the system. Therefore, how to realize the non-reflection of the stopband signal of the filter has gradually become a research hotspot.

According to investigation and understanding, the existing technologies that have been disclosed are as follows:

1) In 2011, Morgan and Boyd first proposed the concept of reflectionless filter, which made the industry refreshing. They gave the circuit topologies and design methods of four reflection-free filters of low-pass, high-pass, band-pass, and band-stop through the formulas, and based on the printed circuit board technology, they used discrete components to process 4th-order 325MHz A reflection-free low-pass filter and a band-pass filter with a center frequency of 210MHz.

2) In 2015, Morgan and Boyd also published a paper in the IEEE-TMTT journal here to promote the lumped component circuit to the filter of the transmission line. This is achieved here by introducing a new approach in which the sub-networks used by the left-hand and right-hand stopband terminations are coupled to each other. The sub-network increases the stop-band attenuation of each filter element and steepens the cut-off response without destroying the reflection-free characteristic. In this paper, a reflection-free circuit topology based on transmission line is also proposed, and a series of MMIC reflection-free low-pass and band-pass reflection-free filters are made.

3) In 2016, Korean scholars such as Lee began to study first-order non-reflection bandpass filters. They used lumped surface mount devices (SMD), and designed and processed a center frequency of 95MHz and a bandwidth of less than 30MHz. Reflectionless bandpass filter.

4) In 2017, Amirhosseini and Taskhiri of Iran University of Science and Technology, on the basis of the above, designed a circuit prototype of a reflection-free low-pass filter with arbitrary odd order and arbitrary stopband attenuation, and processed a third-order center frequency. It is a reflection-free low-pass filter with a stopband attenuation of 20dB at 40MHz.

5) In 2017, Dimitra Psychogiou and Roberto Gómez-García proposed a new single-ended reflection-free filter with no reflection at the input based on the complementary duplex channel structure and coupling routing principle. In addition, based on the principle of coupling routing, the paper analyzes the design conditions of multi-order input without reflection filter and multi-frequency input without reflection filter. Then the first-order tunable non-reflection band-pass filter, tunable band-stop filter and second-order tunable non-reflection band-pass filter and tunable band-stop filter based on centralized components are processed respectively. In addition, first-order and second-order tunable non-reflection bandpass filters based on microstrip lines are also processed.

Utility model content

The purpose of this utility model is to solve the above-mentioned defects of the prior art, and provide a non-reflection bandpass filter, which has the advantages of simple structure, low insertion loss, convenient manufacturing and low cost, and has the advantages of out-of-band reflection. The signal absorption is good, which greatly improves the linearity of the circuit and simplifies the complexity of the circuit.

Another object of the present invention is to provide a radio frequency communication device.

The purpose of the present utility model can be achieved by adopting the following technical solutions:

A non-reflection bandpass filter, comprising a dielectric plate, the lower layer of the dielectric plate is provided with a floor, and the upper layer of the dielectric plate is provided with a first feeder line, a second feeder line, a first band-rejection path, and a second band-rejection path and bandpass paths;

The first feeder is connected to the second feeder through a bandpass path, and the first feeder and the first bandstop path are mirror-symmetrical to the second feeder and the second bandstop path, respectively;

The first band-stop path is connected to the first feeder, and the end of the first band-stop path is loaded with a first resistor, the second band-stop path is connected to the second feeder, and the end of the second band-stop path is loaded with a first resistor. The second resistor, the first band-stop path, the second band-stop path, the first resistor and the second resistor are all connected to the ground through metal through holes.

Further, the first band-stop channel and the second band-stop channel each include a first band-stop branch, a second band-stop branch and a third band-stop branch, and the first band-stop branch of the first band-stop branch is end, the first end of the second band-stop branch and the first end of the third band-stop branch are connected together as the ends of the first band-stop channel and the second band-stop channel, in the first band-stop channel The second end of the first band-stop branch is connected to the first feed line, and the second end of the first band-stop branch in the second band-stop path is connected to the second feed line.

Further, the first band-stop branch is a first bent microstrip line, the first bent microstrip line includes a first horizontal section and a first vertical section, and the first vertical section of the first One end is connected with the first end of the second band resistance branch and the first end of the third band resistance branch, the second end of the second vertical section is connected with the first end of the first horizontal section, and the The second end of the first horizontal segment in the first band-stop path is connected to the first feed line, and the second end of the first horizontal segment in the second band-stop path is connected to the second feed line.

Further, the second band-stop branch is a second bent microstrip line, the second bent microstrip line includes a second horizontal section, a third horizontal section and a second vertical section, the second The first end of the horizontal section is connected with the first end of the first band resistance branch and the first end of the third band resistance branch, and the second end of the second horizontal section is connected to the third horizontal section through the second vertical section. The first ends of the segments are connected.

Further, the third band-stop branch is a third bent microstrip line, the third bent microstrip line includes a fourth horizontal section, a fifth horizontal section and a third vertical section, the fourth The first end of the horizontal section is connected with the first end of the first band resistance branch and the first end of the second band resistance branch, and the second end of the fourth horizontal section is connected to the fifth horizontal section through the third vertical section. The first ends of the segments are connected.

Further, the width of the first band-stop branch is greater than the width of the second band-stop branch, and the width of the second band-stop branch is greater than the width of the third band-stop branch.

Further, the second end of the second band-rejection branch in the first band-rejection path is connected to the floor through the first metal through hole, and the second end of the second band-rejection branch in the second band-rejection path passes through. The second metal through hole is connected to the floor; the first resistor is connected to the floor through the third metal through hole, and the second resistor is connected to the floor through the fourth metal through hole.

Further, the bandpass path is a fourth bent microstrip line, the fourth bent microstrip line includes a sixth horizontal section, a fourth vertical section and a fifth vertical section, the fourth vertical section The first end of the segment is connected to the first feeder, the second end of the fourth vertical segment is connected to the first end of the fifth vertical segment through the sixth horizontal segment, and the second end of the fifth vertical segment is connected to the second feeder connected.

Further, the dielectric plate is a Rogers 5880 plate with a dielectric constant of 2.2 and a loss tangent of 0.0009.

Another object of the present utility model can be achieved by adopting the following technical solutions:

A radio frequency communication device includes the above-mentioned non-reflection bandpass filter.

Compared with the prior art, the utility model has the following beneficial effects:

1. The filter of the present utility model is analyzed and designed in principle. A band-pass path and two mirror-symmetrical band-stop paths are set on the upper layer of the dielectric plate. The ends of the two band-stop paths are loaded with resistors. The spectrum signal passes through the bandpass path from one feed port to another feed port smoothly, while the out-of-band reflected signal passes through the band-rejection path and is absorbed by the grounded resistor, achieving a good out-of-band absorption effect, making the two feeders. All electrical ports can achieve non-reflection characteristics, that is, the filter can well handle the problem of out-of-band reflected waves, so that the reflected waves will not interfere with other components in the radio frequency communication equipment, and will not affect the nonlinearity of the equipment. , reduces the design complexity of the filter, and achieves better non-reflection performance with a simple topology.

2. The filter of the present invention can complete the frequency selection work in the 1.8-2.2GHz frequency band, has good performance, simple structure, easy processing, and can also reduce the number of components in the radio frequency communication equipment, which is equivalent to the original radio frequency communication equipment. The functions of the components for reflected wave processing are integrated to realize the miniaturization of the system.

3. The filter of the present invention is realized by a single-layer dielectric plate, which adopts Rogers 5880 plate with a dielectric constant of 2.2 and a loss tangent of 0.0009, so that the insertion loss of the filter is small.

Description of drawings

FIG. 1 is a schematic diagram of an upper layer structure of a reflection-free bandpass filter according to Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram of the lower layer structure of the reflection-free bandpass filter according to Embodiment 1 of the present invention.

3 is a structural diagram of a first band-stop path in the reflection-free band-pass filter according to Embodiment 1 of the present invention.

FIG. 4 is a structural diagram of a bandpass path in the reflection-free bandpass filter according to Embodiment 1 of the present invention.

FIG. 5 is a transmission efficiency curve diagram of the frequency response of the non-reflection bandpass filter according to Embodiment 1 of the present invention.

Among them, 1-dielectric board, 2-floor, 3-first feeder, 4-second feeder, 5-bandpass, 501-sixth horizontal section, 502-fourth vertical section, 503-fifth vertical Segment, 6-first resistor, 7-second resistor, 8-first band-stop branch, 801-first horizontal segment, 802-first vertical segment, 9-second band-stop branch, 901-th 2nd horizontal section, 902 - third horizontal section, 903 - second vertical section, 10 - third band blocking branch, 1001 - fourth horizontal section, 1002 - fifth horizontal section, 1003 - third vertical section, 11-first metal through hole, 12-second metal through hole, 13-third metal through hole, 14-fourth metal through hole.

Detailed ways

The present utility model will be described in further detail below with reference to the embodiments and the accompanying drawings, but the embodiments of the present utility model are not limited thereto.

Example 1:

As shown in FIG. 1 and FIG. 2 , the reflection-free bandpass filter of this embodiment includes a dielectric board 1 , a floor 2 is provided on the lower layer of the dielectric board 1 , and a first feeder 3 and a second feeder 4 are provided on the upper layer of the dielectric board 1 , the first band-rejection path, the second band-rejection path and the band-pass path 5; the first feeder 3 is connected with the second feeder 4 through the band-pass path, and the first feeder 3 and the first band-rejection path are respectively connected with the second feeder 4, The second band-stop channel is mirror-symmetrical on the left and right; the first band-stop channel is connected to the first feeder 3, and the end of the first band-stop channel is loaded with a first resistor 6 with a resistance value of 50 ohms, and the second band-stop channel is connected to the second The feed line 4 is connected, and the end of the second band-stop path is loaded with a second resistor 7 with a resistance value of 50 ohms. The hole is connected to the floor 2.

Further, the dielectric plate 1 adopts a Rogers 5880 plate with a dielectric constant of 2.2 and a loss tangent of 0.0009, so that the insertion loss of the reflection-free bandpass filter is small; the first feeder 3 serves as a reflection-free bandpass filter The first feed port is located at the left edge of the dielectric board 1 , and the second feed line 4 is used as the second feed port of the non-reflection bandpass filter and is located at the right edge of the dielectric board 1 .

Since the first band-stop channel and the second band-stop channel are mirror symmetrical on the left and right, the first band-stop channel and the second band-stop channel have the same structure. Taking the first band-stop channel as an example, as shown in FIG. The blocking branch 8 , the second blocking branch 9 and the third blocking branch 10 , the first blocking branch 8 , the second blocking branch 9 and the third blocking branch 10 all have a first end and The second end opposite to the first end, the first end of the first band-stop branch 8, the first end of the second band-stop branch 9 and the first end of the third band-stop branch 10 are connected together as At the end of the first band-rejection path, the second end of the first band-rejection branch 8 is connected to the first feeder 3; similarly, in the second band-rejection path, the first end of the first band-rejection branch 8, the first The first end of the second band-stop branch 9 and the first end of the third band-stop branch 10 are connected together, and as the end of the second band-stop path, the second end of the first band-stop branch 8 is connected to the second feeder 4 are connected.

Specifically, the width of the first band-stop branch 8 is greater than the width of the second band-stop branch 9, and the width of the second band-stop branch 9 is greater than the width of the third band-stop branch 10; , the second end of the second band-stop branch 9 is connected to the floor 2 through the first metal through hole 11, and in the second band-stop channel, the second end of the second band-stop branch 9 passes through the second metal through hole 12 is connected to the floor 2 ; the first resistor 6 is connected to the floor 2 through the third metal through hole 13 , and the second resistor 7 is connected to the floor 2 through the fourth metal through hole 14 .

Further, the first band-stop branch 8 is a first bent microstrip line, and the total electrical length of the first bent microstrip line is 90°, which includes a first horizontal section 801 and a first vertical section 802, the first The second band-stop branch 9 is a second bent microstrip line, and the total electrical length of the second bent microstrip line is 90°, which includes a second horizontal section 901 , a third horizontal section 902 and a second vertical section 903 , the third band-stop branch 10 is a third bent microstrip line, and the total electrical length of the third bent microstrip line is 90°, which includes a fourth horizontal section 1001, a fifth horizontal section 1002 and a third vertical section Section 1003; first horizontal section 801, first vertical section 802, second horizontal section 901, third horizontal section 902, second vertical section 903, fourth horizontal section 1001, fifth horizontal section 1002 and third vertical section The straight sections 1003 each have a first end and a second end opposite to the first end, the first end of the first vertical section 802 serves as the first end of the first band-stop branch 8 , the first The end is used as the first end of the second band resistance branch 9, the first end of the fourth horizontal section 1001 is used as the first end of the third band resistance branch 10, that is, the first end of the first vertical section 802, the second end The first end of the horizontal section 901 is connected with the first end of the fourth horizontal section 1001, the second end of the first vertical section 802 is connected with the first end of the first horizontal section 801, and the first end of the first horizontal section 801 is connected to the first end of the first horizontal section 801. The two ends serve as the second ends of the first band-stop branch 8. In the first band-stop channel, the second end of the first horizontal section 801 is connected to the first feeder 3. In the second band-stop channel, the first horizontal section 801 is connected to the first feeder line 3. The second end of the segment 801 is connected to the second feeder 4; the second end of the second horizontal segment 901 is connected to the first end of the third horizontal segment 902 through the second vertical segment 903, and the second end of the third horizontal segment 902 As the second end of the second band-stop branch 9, in the first band-stop channel, the second end of the third horizontal segment 902 extends to the left of the first vertical segment 802 and passes through the first metal through hole 11 Connected to the floor 2, in the second band resistance path, the second end of the third horizontal section 902 extends to the right of the first vertical section 802, and is connected to the floor 2 through the second metal through hole 12; the fourth horizontal section 902 is connected to the floor 2. The second end of the segment 1001 is connected to the first end of the fifth horizontal segment 1002 through the third vertical segment 1003, and the second end of the fifth horizontal segment 1002 serves as the second end of the third band-stop branch 10. In the band-stop path, the second end of the fifth horizontal segment 1002 extends to the left side of the dielectric board 1 , and in the second band-stop path, the second end of the fifth horizontal segment 1002 extends to the right side of the dielectric board 1 .

The bandpass path 5 in this embodiment is a fourth bent microstrip line. As shown in FIG. 4 , the total electrical length of the fourth bent microstrip line is 180°, which includes a sixth horizontal section 501 , a fourth vertical section Section 502 and fifth vertical section 503, the first end of the fourth vertical section 502 is connected to the first feeder 3, and the second end of the fourth vertical section 502 is connected to the fifth vertical section 503 through the sixth horizontal section 501 The first end of the fifth vertical segment is connected to the second feeder line 4 .

The working principle of the non-reflection bandpass filter in this embodiment is: the spectral signal in the passband passes through the bandpass path 5 smoothly from the first feeding port to the second feeding port; for the first bandstop path, the out-of-band reflection The signal passes through the first band-stop path and is absorbed by the grounded first resistor 6. Similarly, for the second band-stop path, the out-of-band reflected signal passes through the second band-stop path and is absorbed by the grounded second resistor 7. A good out-of-band absorption effect is achieved, so that both the first feeding port and the second feeding port can achieve non-reflection characteristics.

The transmission efficiency curve diagram of the frequency response of the non-reflection bandpass filter of this embodiment is shown in FIG. 5 , in which |S ₁₁ | represents the return loss of the first feeding port, and |S ₂₁ | represents the first feeding From the forward transmission coefficient from the port to the second feed port, it can be seen that the center frequency of the non-reflection bandpass filter in this embodiment is about 2.0GHz, which can complete the frequency selection work in the 1.8-2.2GHz frequency band, and the out-of-band is certain. Reflected signals in the frequency range are absorbed, enabling good out-of-band reflection-free characteristics.

Example 2:

This embodiment provides a radio frequency communication device, which may be a mobile phone, a tablet computer, or the like, which includes the reflection-free bandpass filter of the above-mentioned Embodiment 1.

To sum up, the filter of the present invention is analyzed and designed in principle, a band-pass path and two mirror-symmetrical band-stop paths are set on the upper layer of the dielectric plate, and the ends of the two band-stop paths are loaded with resistors. The spectral signal of the passband passes through the bandpass path from one feed port to another feed port smoothly, while the out-of-band reflected signal passes through the band-rejection path and is absorbed by the grounding resistance, so that both feed ports can achieve no noise. The characteristics of reflection, that is, the filter can handle the problem of out-of-band reflected waves well, so that the reflected waves will not interfere with other components in the radio frequency communication equipment, and will not affect the nonlinearity of the equipment, reducing the filter The design complexity is low, and the better non-reflection performance can be achieved with a simple topology.

The above is only a preferred embodiment of the patent for this utility model, but the protection scope of the patent for this utility model is not limited to this. The technical solution of the utility model patent and its utility model concept are equivalently replaced or changed, which all belong to the protection scope of the utility model patent.

Claims (10)

1. A non-reflection bandpass filter, comprising a dielectric plate, the lower layer of the dielectric plate is provided with a floor, and it is characterized in that: the upper layer of the dielectric plate is provided with a first feeder, a second feeder, and a first band-stop path , the second band-stop path and the band-pass path; The first feeder is connected to the second feeder through a bandpass path, and the first feeder and the first bandstop path are mirror-symmetrical to the second feeder and the second bandstop path, respectively; The first band-stop path is connected to the first feeder, and the end of the first band-stop path is loaded with a first resistor, the second band-stop path is connected to the second feeder, and the end of the second band-stop path is loaded with a first resistor. The second resistor, the first band-stop path, the second band-stop path, the first resistor and the second resistor are all connected to the ground through metal through holes. 2 . The reflection-free bandpass filter according to claim 1 , wherein the first band-stop path and the second band-stop path both comprise a first band-stop branch, a second band-stop branch and a first band-stop branch. 3 . Three band-stop branches, the first end of the first band-stop branch, the first end of the second band-stop branch and the first end of the third band-stop branch are connected together to form a first band-stop path and the end of the second band-stop channel, the second end of the first band-stop branch in the first band-stop channel is connected to the first feeder, and the second band-stop branch of the second band-stop channel The end is connected to the second feeder. 3 . The reflection-free bandpass filter according to claim 2 , wherein the first band-stop branch is a first bent microstrip line, and the first bent microstrip line comprises a first horizontal line. 4 . section and a first vertical section, the first end of the first vertical section is connected with the first end of the second band resistance branch and the first end of the third band resistance branch, and the second vertical section The second end of the first horizontal section is connected to the first end of the first horizontal section, the second end of the first horizontal section in the first band resistance path is connected to the first feeder, and the second end of the first horizontal section in the second band resistance path The second end is connected to the second feeder. 4 . The non-reflection bandpass filter according to claim 2 , wherein the second band-stop branch is a second meandering microstrip line, and the second meandering microstrip line comprises a second horizontal line. 5 . section, a third horizontal section and a second vertical section, the first end of the second horizontal section is connected with the first end of the first band resistance branch and the first end of the third band resistance branch, the first The second ends of the two horizontal sections are connected to the first end of the third horizontal section through the second vertical section. 5 . The reflection-free bandpass filter according to claim 2 , wherein the third band-stop branch is a third folded microstrip line, and the third folded microstrip line comprises a fourth horizontal line. 6 . section, a fifth horizontal section and a third vertical section, the first end of the fourth horizontal section is connected with the first end of the first band resistance branch and the first end of the second band resistance branch, the first The second ends of the four horizontal segments are connected to the first ends of the fifth horizontal segment through the third vertical segment. 6. The reflection-free bandpass filter according to any one of claims 2-5, wherein the width of the first band-stop branch is greater than the width of the second band-stop branch, and the second band-stop branch has a width greater than that of the second band-stop branch. The width of the branch is greater than the width of the third band-stop branch. 7. The non-reflective bandpass filter according to any one of claims 2-5, wherein the second end of the second bandstop branch in the first bandstop path is connected to the first metal through hole through the first metal through hole. connected to the floor, the second end of the second band-resistance branch in the second band-resistance path is connected to the floor through a second metal through hole; the first resistor is connected to the floor through a third metal through hole, and the second The resistor is connected to the floor through the fourth metal through hole. 8. The non-reflective bandpass filter according to any one of claims 1-5, wherein the bandpass path is a fourth bent microstrip line, and the fourth bent microstrip line comprises a Six horizontal sections, a fourth vertical section and a fifth vertical section, the first end of the fourth vertical section is connected to the first feeder, and the second end of the fourth vertical section is connected to the fifth vertical section through the sixth horizontal section The first end of the vertical section is connected to the second end of the fifth vertical section is connected to the second feeder. 9 . The non-reflection bandpass filter according to claim 1 , wherein the dielectric plate is a Rogers 5880 plate with a dielectric constant of 2.2 and a loss tangent of 0.0009. 10 . 10. A radio frequency communication device, characterized in that it comprises the reflection-free bandpass filter according to any one of claims 1-9.

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