CN111710948A

CN111710948A - Combiner

Info

Publication number: CN111710948A
Application number: CN202010419605.XA
Authority: CN
Inventors: 冯波涛; 陈均龙; 梁胜
Original assignee: South Star Technology Ltd
Current assignee: South Star Technology Ltd
Priority date: 2020-05-18
Filing date: 2020-05-18
Publication date: 2020-09-25
Anticipated expiration: 2040-05-18
Also published as: CN111710948B

Abstract

The invention discloses a combiner, which comprises a substrate, wherein the substrate comprises a first surface and a second surface which are oppositely arranged, the second surface is coated with copper and grounded, and the first surface is provided with a micro-strip circuit: the low-pass filter is used for filtering signals of a 5G frequency band, a 3G frequency band and an LTE frequency band, the high-pass filter is used for filtering signals of a 2G frequency band, a 3G frequency band and an LTE frequency band, and the band-pass filter is used for filtering signals of the 2G frequency band and the 5G frequency band; one end of each of the low-pass filter, the high-pass filter and the band-pass filter is connected with the first port through the same impedance adjusting part and is a closed end; and the other ends of the low-pass filter, the high-pass filter and the band-pass filter are respectively connected with the second port, the fourth port and the third port and are shunt ends. The combiner can efficiently and accurately divide the signal containing multiple frequency bands into a plurality of signals only containing a single frequency band.

Description

Combiner

Technical Field

The invention relates to the technical field of wireless communication, in particular to a combiner.

Background

With the advent of the 5G era, the frequency bands used for wireless communication have been increasing, and many designers of communication devices have only designed the latest frequency band, but now in a transitional period, the old frequency band and the latest frequency band need to be utilized to meet the communication demands of different users and different devices. Therefore, it is necessary to design a combiner capable of combining signals of 2G frequency band, 3G and LTE frequency band, and 5G frequency band commonly used for wireless communication. The combiner needs to combine signals of different frequency bands into one path at a transmitting end, uniformly transmits the signals and transmits the signals to different indoor distribution systems or cell base stations; the signals collected with different frequency bands need to be separated at the receiving end, so that the signals with different frequency bands can be radiated independently.

Disclosure of Invention

The invention provides a combiner which can efficiently and accurately divide a signal containing multiple frequency bands into a plurality of signals only containing a single frequency band.

In order to achieve the above object, the present invention provides a combiner, including a substrate, where the substrate includes a first surface and a second surface that are oppositely disposed, the second surface is copper-clad and grounded, and the first surface is provided with a microstrip line:

a low pass filter for filtering signals of 5G frequency band, 3G frequency band and LTE frequency band,

a high pass filter for filtering signals of 2G frequency band, 3G frequency band and LTE frequency band,

the band-pass filter is used for filtering signals of a 2G frequency band and a 5G frequency band;

one end of each of the low-pass filter, the high-pass filter and the band-pass filter is connected with the first port through the same impedance adjusting part and is a closed end; and the other ends of the low-pass filter, the high-pass filter and the band-pass filter are respectively connected with the second port, the fourth port and the third port and are shunt ends.

Preferably, two interdigital microstrip branches are sequentially arranged on the main channel of the low-pass filter, so that the transmission coefficient of signals in a 2G frequency band is larger than-1.5 dB, and the transmission coefficients of signals in a 5G frequency band, a 3G frequency band and an LTE frequency band are smaller than-15 dB.

Preferably, the main channel of the band-pass filter is sequentially provided with an L-shaped microstrip branch and an arc-shaped microstrip branch, so that the transmission coefficients of the signals in the 3G and LTE frequency bands are larger than-1.5 dB, and the transmission coefficients of the signals in the 2G frequency band and the 5G frequency band are smaller than-15 dB.

Preferably, two L-shaped microstrip branches are sequentially arranged on the main channel of the high-pass filter, so that the transmission coefficient of signals in a 5G frequency band is greater than-1.5 dB, and the transmission coefficients of signals in a 2G frequency band, a 3G frequency band and an LTE frequency band are less than-15 dB.

Preferably, two U-shaped microstrip lines with opposite opening directions are sequentially arranged on the main channel of the low-pass filter, so that the transmission coefficient of signals in a 2G frequency band is larger than-1.5 dB, and the transmission coefficients of signals in a 5G frequency band, a 3G frequency band and an LTE frequency band are smaller than-15 dB.

Preferably, the band-pass filter is composed of a plurality of sections of sequentially coupled microstrip lines, two ends of the microstrip lines are linear microstrip lines, the middle of the microstrip lines is at least two U-shaped microstrip lines, the U-shaped microstrip lines are distributed in an interdigital shape to form an S-shaped or continuous S-shaped structure, so that the transmission coefficients of signals in 3G and LTE frequency bands are larger than-1.5 dB, and the transmission coefficients of signals in 2G and 5G frequency bands are smaller than-15 dB.

Preferably, the high-pass filter is composed of a plurality of microstrip lines distributed in a step shape, and the adjacent microstrip lines are coupled with each other, so that the transmission coefficient of signals in a 5G frequency band is larger than-1.5 dB, and the transmission coefficients of signals in a 2G frequency band, a 3G frequency band and an LTE frequency band are smaller than-15 dB.

Preferably, the impedance adjusting part includes four mutually communicated microstrip branches, one of which is connected to the first port, and the other three of which are connected to the main channels of the low-pass filter, the high-pass filter, and the band-pass filter, respectively.

Preferably, the impedance adjusting part includes three mutually communicated microstrip branches, one of the microstrip branches is connected to the first port, the other two microstrip branches are respectively connected to the low-pass filter and the high-pass filter, and one end of the band-pass filter is connected to the middle part of the impedance adjusting part.

As can be seen from the above description and practice, the combiner according to the present invention can effectively separate and transmit signals including two or three frequency bands by arranging the low pass filter, the band pass filter, the high pass filter, and the impedance adjusting portion on the dielectric substrate, and can also implement impedance matching of each frequency band at the combining end. Each filter can ensure that the transmission coefficient of the frequency band is larger than-1.5 dB until the transmission coefficient is close to 0, and simultaneously can ensure that the transmission coefficient of signals of other frequency bands is smaller than-15 dB, thereby realizing high-efficiency filtering. In addition, the structural design and the layout method of each filter in the embodiment can effectively avoid the coupling of signals among the filters, and enhance the filtering effect of the combiner.

Drawings

Fig. 1 is a schematic structural diagram of a combiner according to a first embodiment of the present invention.

Fig. 2 is a schematic structural diagram of an impedance adjusting unit according to a first embodiment of the present invention.

Fig. 3 is a diagram illustrating reflection coefficients of signals of different frequencies in the impedance adjusting section according to the first embodiment of the present invention.

Fig. 4 is a diagram illustrating transmission coefficients of signals with different frequencies in each filter according to a first embodiment of the present invention.

Fig. 5 is a schematic structural diagram of a combiner according to a second embodiment of the present invention.

Fig. 6 is a schematic structural diagram of an impedance adjusting section according to a second embodiment of the present invention.

Fig. 7 is a diagram showing reflection coefficients of signals of different frequencies in the impedance adjusting section according to the second embodiment of the present invention.

Fig. 8 shows transmission coefficients of signals of different frequencies in the respective filters according to the second embodiment of the present invention.

In the figure:

1. a substrate; 2. a low-pass filter; 3. a band-pass filter; 4. a high-pass filter; 5. an impedance adjusting section; 6. a first port; 7. a second port; 8. a third port; 9. a fourth port.

Detailed Description

Exemplary embodiments will now be described more fully with reference to the accompanying drawings. The exemplary embodiments, however, may be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

Furthermore, the drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repetitive description will be omitted. In the present disclosure, the terms "include", "arrange", "disposed" and "disposed" are used to mean open-ended inclusion, and mean that there may be additional elements/components/etc. in addition to the listed elements/components/etc.; the terms "first," "second," and the like are used merely as labels, and are not limiting as to the number or order of their objects; the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings for convenience in describing the invention and for simplicity in description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be construed as limiting the invention.

Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example one

Fig. 1 is a schematic structural diagram of a combiner according to a first embodiment of the present invention, which shows a structure of a first surface of the combiner. Fig. 2 is a schematic structural diagram of an impedance adjusting unit according to a first embodiment of the present invention.

As shown in fig. 1, the combiner includes a substrate 1 made of an FR-4 board, the substrate 1 having a dielectric constant of 2.6 and a thickness of 1 mm. The substrate 1 includes a first surface and a second surface (not shown) opposite to each other, the second surface is copper-clad and grounded, and the first surface is provided with a combiner structure composed of microstrip lines.

Referring to fig. 1, a band-pass filter 3, a high-pass filter 4 and a low-pass filter 2 are sequentially disposed on a first surface of a substrate 1 from top to bottom. The structures of the band-pass filter 3, the high-pass filter 4 and the low-pass filter 2 are different, and the transmission coefficients of signals in different frequency bands are different. Each filter adjusts the transmission coefficient of signals of different frequency bands by adjusting the shape and the size of the filter, so that the filtering is realized. The band-pass filter 3 only allows signals with the frequency within the range of 1.71GHz-2.69GHz to pass, namely only allows signals in 3G and LTE frequency bands to pass; the high-pass filter 4 only allows signals with the frequency within the range of 3.3GHz-3.8GHz to pass, namely only allows signals in the 5G frequency band to pass; the low-pass filter 2 allows only signals with frequencies in the range of 0.81GHz-0.96GHz to pass, i.e. only signals in the 2G band.

In this embodiment, the band-pass filter 3, the high-pass filter 4, and the low-pass filter 2 are arranged in parallel, one end of the left side thereof is connected to the first port 6 through the impedance adjusting section 5, and the first port 6 is a junction end, that is, the band-pass filter 3, the high-pass filter 4, and the low-pass filter 2 input or output signals through the same feeder line and via the first port 6. The right end of the band-pass filter 3 is connected with the third port 8, the right end of the high-pass filter 4 is connected with the fourth port 9, and the right end of the low-pass filter 2 is connected with the second port 7. The second port 7, the third port 8 and the fourth port 9 are shunt ports. Needless to say, the arrangement positions of the band-pass filter 3, the high-pass filter 4 and the low-pass filter 2 can be changed according to the actual structural design requirements, for example, the three can be arranged in a radial manner, the combining end is arranged in the center, the splitting end is arranged around, and the effect of the combiner can be realized.

As shown in fig. 2, the impedance adjusting part 5 is composed of four mutually communicated microstrip branches, wherein a microstrip branch extends leftwards from the middle of the impedance adjusting part, and the tail end of the impedance adjusting part is connected with the first port 6; a micro-strip branch extends upwards, and the tail end of the micro-strip branch is connected with the left end of the band-pass filter 3; a microstrip branch extends rightwards from the middle part of the filter, and the tail end of the microstrip branch is connected with the left end of the high-pass filter 4; an L-shaped microstrip branch is further extended downwards, and the tail end of the microstrip branch is connected with the left end of the low-pass filter 2. The impedance adjusting part 5 is used for realizing impedance matching of all frequency bands (2G frequency bands, 3G and LTE frequency bands and 5G frequency bands) at the first port 6, so that the reflection coefficients of signals of the 2G frequency bands, the 3G and LTE frequency bands and the 5G frequency bands are all smaller than-15 dB, and the requirement of the combiner in industry is met. Specifically, impedance matching is realized by adjusting the lengths and widths of the four microstrip branches of the impedance adjusting section 5. The implementation of impedance matching by the length and width of the microstrip line is prior art and will not be described herein.

As shown in fig. 1, the bandpass filter 3 is formed by a microstrip line, and an L-shaped microstrip branch and an arc-shaped microstrip branch are sequentially disposed in a main channel thereof. Wherein, the L-shaped microstrip branch is close to one end of the impedance adjusting part 5, and the bent end of the microstrip branch faces the impedance adjusting part 5. The arc-shaped microstrip branch is arranged on one side close to the third port 8 and is connected with the main channel through a linear microstrip line. By arranging the two microstrip branches, the transmission coefficients of the signals in the 2G frequency band and the 5G frequency band on the band-pass filter 3 can be smaller than-15 dB, and the transmission coefficients of the signals in the 3G frequency band and the LTE frequency band on the band-pass filter 3 are larger than-1.5 dB until the transmission coefficients are close to 0. I.e. a third transmission zero for the low band (2G band) and a fourth transmission zero for the high band (5G band) compared to the 3G and LTE bands. Therefore, the band-pass filter 3 has an efficient transmission effect only for signals in the 3G and LTE bands, and signals in the 5G band and the 2G band cannot be transmitted therethrough, so that a filtering effect is achieved. The impedance matching of the band-pass filter 3 itself can be achieved by adjusting the length and width of its main channel.

As shown in fig. 1, the high-pass filter 4 is formed by a microstrip line, and two L-shaped microstrip branches are sequentially arranged on a main channel of the microstrip line. The direction of the bending portions of the two L-shaped microstrip branch circuits is opposite, specifically, the bending portion of the L-shaped microstrip branch circuit near the impedance adjusting portion 5 is toward the left side, and the bending portion of the L-shaped microstrip branch circuit near the fourth port 9 is toward the right side. By arranging the two microstrip branches, the transmission coefficients of signals in the 2G frequency band, the 3G frequency band and the LTE frequency band on the high-pass filter 4 can be smaller than-15 dB, and the transmission coefficient of signals in the 5G frequency band on the high-pass filter 4 is larger than-1.5 dB until the transmission coefficients are close to 0. I.e. a second transmission zero for the low frequency bands (2G band, 3G and LTE band) is formed, where the low frequency bands are compared to the 5G band. Therefore, the high-pass filter 4 has an efficient transmission effect only for signals in the 5G band, but signals in the 2G band, the 3G band and the LTE band cannot be transmitted therethrough, so that a filtering effect is achieved. The impedance matching of the high pass filter 4 itself can then be achieved by adjusting the length and width of its main channel.

As shown in fig. 1, the low-pass filter 2 is formed by a microstrip line, and two interdigital microstrip branches are sequentially disposed on a main channel thereof. By arranging the two branches, the transmission coefficient of the signals of the 3G and LTE frequency bands and the 5G frequency band on the low-pass filter 2 can be smaller than-15 dB, and the transmission coefficient of the signals of the 2G frequency band on the low-pass filter 2 is larger than-1.5 dB till close to 0. I.e. a first transmission zero for the high frequency band (3G and LTE bands and 5G band) is formed, where the high frequency band is compared to the 2G band. Therefore, the low-pass filter 2 has an efficient transmission effect only for signals in the 2G band, but signals in the 3G and LTE bands and the 5G band cannot be transmitted therethrough, so that a filtering effect is achieved. The impedance matching of the low-pass filter 2 itself can be achieved by adjusting the length and width of its main channel.

Fig. 3 is a diagram illustrating reflection coefficients of signals of different frequencies in the impedance adjusting section according to the first embodiment of the present invention. FIG. 4 shows the transmission coefficients of signals with different frequencies in the filters involved in the first embodiment of the present invention, where S₁₂For transmission coefficients of signals of different frequencies in a low-pass filter, S₁₃Is a band-pass filterTransmission coefficient of signals of different frequencies, S₁₄Are the transmission coefficients of the signals of different frequencies in the high-pass filter.

The combiner in this embodiment is connected to a calibrated network analyzer (model number, aglent E5071C), and then the reflection coefficient of the impedance matching section 5 and the transmission coefficient of each filter are tested, and the specific test results are shown in fig. 3 and fig. 4.

It can be seen from fig. 3 that the reflection coefficients of the signals in the 2G frequency band (0.81GHz-0.96GHz), the 3G and LTE frequency bands (1.71GHz-2.69GHz) and the 5G frequency band (3.3GHz-3.8GHz) on the impedance adjusting section 5 are all less than-15 dB, which meets the requirements of industrial design.

It can be seen from fig. 4 that the transmission coefficient of the signal in the 0.81GHz-0.96GHz band on the low-pass filter 2 is greater than-1 dB until it is close to 0, and the transmission coefficients of the signal in the 1.71GHz-2.69GHz band and the signal in the 3.3GHz-3.8GHz band are less than-15 dB, which meets the standard of industrial design and can meet the requirements of filtering the signal in the 5G band, the 3G band and the LTE band; the transmission coefficient of the signals of the 1.71GHz-2.69GHz frequency band on the band-pass filter 3 is greater than-1 dB until the signals are close to 0, and the transmission coefficients of the signals of the 0.81GHz-0.96GHz frequency band and the 3.3GHz-3.8GHz frequency band are less than-15 dB, so that the standard of industrial design is met, and the requirements of filtering the signals of the 2G frequency band and the 5G frequency band can be realized; the transmission coefficient of the signals of the 3.3GHz-3.8GHz band on the high-pass filter 4 is larger than-1.5 dB until the signals are close to 0, and the transmission coefficients of the signals of the 0.81GHz-0.96GHz band and the 1.71GHz-2.69GHz band are smaller than-15 dB, so that the standard of industrial design is met, and the requirements of filtering the signals of the 2G band, the 3G band and the LTE band can be realized.

The combiner disclosed in this embodiment is applied to a receiving end, for example, and the signals containing multiple frequency bands at the receiving end need to be separated so as to transmit the signals of the frequency bands to corresponding antennas for radiation. For example, a signal including a 2G band, a 3G band, an LTE band, and a 5G band is input to the combiner from the first port 6, and then transmitted to the low-pass filter 2, the band-pass filter 3, and the high-pass filter 4 via the impedance adjusting section 5, and each filter filters a signal including a plurality of bands, and finally, a signal of only the 2G band is output from the second port 7, a signal of only the 3G band and the LTE band is output from the third port 8, and a signal of only the 5G band is output from the fourth port 9. The second port 7 may be connected to a 2G antenna, so as to radiate signals in the 2G frequency band; the third port 8 may be connected to a 3G, LTE antenna to radiate signals in the 3G and LTE bands; the fourth port 9 may be connected to a 5G antenna for radiating signals in the 5G band.

The combiner disclosed in this embodiment can effectively separate and transmit signals including two or three frequency bands, and impedance matching of each frequency band can be realized at the combining end. Each filter can ensure that the transmission coefficient of the frequency band is larger than-1.5 dB until the transmission coefficient is close to 0, and simultaneously can ensure that the transmission coefficient of signals of other frequency bands is smaller than-15 dB, thereby realizing high-efficiency filtering. In addition, the structural design and the layout method of each filter in the embodiment can effectively avoid the coupling of signals among the filters, and enhance the filtering effect of the combiner.

Example two

Fig. 5 is a schematic structural view of a combiner according to a second embodiment of the present invention, which shows a structure of a first surface of the combiner. Fig. 6 is a schematic structural diagram of an impedance adjusting section according to a second embodiment of the present invention.

As shown in fig. 5, the combiner includes a substrate 1 made of an FR-4 board, the substrate 1 having a dielectric constant of 2.6 and a thickness of 1 mm. The substrate 1 includes a first surface and a second surface (not shown) opposite to each other, the second surface is copper-clad and grounded, and the first surface is provided with a combiner structure composed of microstrip lines.

Referring to fig. 5, a low pass filter 2, a band pass filter 3 and a high pass filter 4 are sequentially disposed on the front surface of the substrate 1 from top to bottom. The low-pass filter 2, the band-pass filter 3 and the high-pass filter 4 have different structures, and the transmission coefficients of signals in different frequency bands are different. Each filter adjusts the transmission coefficient of signals of different frequency bands by adjusting the shape and the size of the filter, so that the filtering is realized. Wherein the low-pass filter 2 only allows signals with the frequency in the range of 0.81GHz-0.96GHz to pass, namely only allows signals in the 2G frequency band to pass; the band-pass filter 3 only allows signals with the frequency within the range of 1.71GHz-2.69GHz to pass, namely only allows signals of 3G and LTE frequency bands to pass; the high-pass filter 4 allows only signals with frequencies in the range of 3.3GHz-3.8GHz, i.e. only signals in the 5G band.

In this embodiment, the low-pass filter 2, the band-pass filter 3, and the high-pass filter 4 are arranged in parallel, one end of the left side thereof is connected to the first port 6 through the impedance adjusting section 5, and the first port 6 is a junction end, that is, the low-pass filter 2, the band-pass filter 3, and the high-pass filter 4 input or output signals through the same feeder line and via the first port 6. The right end of the low-pass filter 2 is connected with the second port 7, the right end of the band-pass filter 3 is connected with the third port 8, and the right end of the high-pass filter 4 is connected with the fourth port 9. The second port 7, the third port 8 and the fourth port 9 are shunt ports. Needless to say, the arrangement positions of the band-pass filter 3, the high-pass filter 4 and the low-pass filter 2 can be changed according to the actual structural design requirements, for example, the three can be arranged in a radial manner, the combining end is arranged in the center, the splitting end is arranged around, and the effect of the combiner can be realized.

As shown in fig. 6, the impedance adjusting part 5 is composed of three mutually communicated microstrip branches, wherein the microstrip branch extending leftwards in the middle is connected with the first port 6; the upward extending microstrip branch is connected with the left end of the low-pass filter 2; the downward microstrip branch is L-shaped, and the tail end of the microstrip branch is connected with the left end of the high-pass filter 4; and the left end of the band-pass filter 3 is directly connected to the middle of the impedance adjusting section 5. The impedance adjusting part 5 is used for realizing impedance matching of all frequency bands (2G frequency bands, 3G and LTE frequency bands and 5G frequency bands) at the first port 6, so that the reflection coefficients of signals of the 2G frequency bands, the 3G and LTE frequency bands and the 5G frequency bands are all smaller than-10 dB, and the requirement of the combiner in industry is met. Specifically, impedance matching is realized by adjusting the lengths and widths of the three microstrip branches of the impedance adjusting section 5. The implementation of impedance matching by the length and width of the microstrip line is prior art and will not be described herein.

As shown in fig. 6, the low-pass filter 2 is formed by a microstrip line, and two U-shaped microstrip lines are sequentially arranged on the main channel, wherein the opening of the U-shaped microstrip line near one end of the impedance adjusting section 5 is leftward, the opening of the U-shaped microstrip line near one end of the second port 7 is rightward, and the two U-shaped microstrip lines have different lengths. The left end of the main channel of the low-pass filter 2 is directly connected with the upper microstrip branch of the impedance adjusting part 5, and the right end of the main channel of the low-pass filter 2 is directly connected with the second port 7. By arranging the two U-shaped microstrip lines on the main channel of the low-pass filter 2, the transmission coefficients of signals in 3G and LTE frequency bands and 5G frequency bands on the low-pass filter 2 can be smaller than-15 dB, and the transmission coefficient of signals in the 2G frequency band on the low-pass filter 2 is larger than-1 dB till close to 0. I.e. a first transmission zero for the high frequency band (3G and LTE bands and 5G band) is formed, where the high frequency band is compared to the 2G band. Therefore, the low-pass filter 2 has an efficient transmission effect only for signals in the 2G band, but signals in the 3G and LTE bands and the 5G band cannot be transmitted therethrough, so that a filtering effect is achieved. The impedance matching of the low-pass filter 2 itself can be achieved by adjusting the length and width of its main channel.

As shown in fig. 6, the band-pass filter 3 is composed of six sequentially coupled microstrip lines, two ends of the microstrip line are linear microstrip lines, the middle of the microstrip line is two U-shaped microstrip lines, and two adjacent microstrip lines are coupled with each other. Wherein, two U-shaped microstrip lines in the middle part are distributed in an interdigital shape and form an S-shaped structure. The number of the U-shaped microstrip lines in the middle can be increased according to actual requirements, but each U-shaped microstrip line should be arranged in an interdigital manner and form a continuous S-shaped structure. The section of microstrip line at the leftmost end of the band-pass filter 3 is directly connected with the middle part of the impedance adjusting part 5, and the microstrip line at the rightmost end of the band-pass filter 3 is directly connected with the third port 8. By arranging the six sections of sequentially coupled microstrip lines and adjusting the distance between the adjacent sections of microstrip lines, the transmission coefficients of signals in the 2G frequency band and the 5G frequency band on the band-pass filter 3 can be smaller than-15 dB, and the transmission coefficients of signals in the 3G frequency band and the LTE frequency band on the band-pass filter 3 are larger than-1 dB until the transmission coefficients are close to 0. I.e. a third transmission zero for the low band (2G band) and a fourth transmission zero for the high band (5G band) compared to the 3G and LTE bands. Therefore, the band-pass filter 3 has an efficient transmission effect only for signals in the 3G and LTE bands, and signals in the 5G band and the 2G band cannot be transmitted therethrough, so that a filtering effect is achieved. The impedance matching of the band-pass filter 3 itself can be realized by adjusting the number, length and width of the microstrip lines.

As shown in fig. 6, the high-pass filter 4 is composed of six microstrip lines distributed in a step shape, and the microstrip lines descend from left to right in sequence, and two adjacent microstrip lines are coupled with each other. The microstrip branch at the lower end of the impedance adjusting part 5 is L-shaped, and the right end of the impedance adjusting part is directly connected with a section of microstrip line at the leftmost end of the high-pass filter 4. The microstrip line at the rightmost end of the high-pass filter 4 is directly connected to the fourth port 9. By arranging the six sections of sequentially coupled microstrip branches and adjusting the distance between adjacent sections of microstrip lines, the transmission coefficients of signals in the 2G frequency band, the 3G frequency band and the LTE frequency band on the high-pass filter 4 can be smaller than-15 dB, and the transmission coefficient of signals in the 5G frequency band on the high-pass filter 4 is larger than-1 dB until the transmission coefficient is close to 0. I.e. a second transmission zero for the low frequency bands (2G band, 3G and LTE band) is formed, where the low frequency bands are compared to the 5G band. Therefore, the high-pass filter 4 has an efficient transmission effect only for signals in the 5G band, but signals in the 2G band, the 3G band and the LTE band cannot be transmitted therethrough, so that a filtering effect is achieved. The impedance matching of the high pass filter 4 itself can then be achieved by adjusting the length and width of its main channel.

Fig. 7 is a diagram showing reflection coefficients of signals of different frequencies in the impedance adjusting section according to the second embodiment of the present invention. FIG. 8 is a diagram showing transmission coefficients of signals of different frequencies in respective filters according to a second embodiment of the present invention, where S₁₂For transmission coefficients of signals of different frequencies in a low-pass filter, S₁₃For transmission coefficients of signals of different frequencies in band-pass filters, S₁₄Are the transmission coefficients of the signals of different frequencies in the high-pass filter.

The combiner in this embodiment is connected to a calibrated network analyzer (model number, aglent E5071C), and then the reflection coefficient of the impedance matching section 5 and the transmission coefficient of each filter are tested, and the specific test results are shown in fig. 7 and 8.

It can be seen from fig. 7 that the reflection coefficients of the signals in the 2G frequency band (0.81GHz-0.96GHz), the 3G and LTE frequency bands (1.71GHz-2.69GHz), and the 5G frequency band (3.3GHz-3.8GHz) on the impedance adjusting section 5 are all less than-10 dB, which meet the standard of industrial design and can meet practical application.

It can be seen from fig. 8 that the transmission coefficient of the 0.81GHz-0.96GHz band signal on the low pass filter 2 is greater than-1 dB until it is close to 0, while the transmission coefficient of the 1.71GHz-2.69GHz band signal is less than-15 dB, and the transmission coefficient of the 3.3GHz-3.8GHz band signal is less than-44 dB, which meets the standard of industrial design and can realize the requirements of filtering 5G band, 3G band and LTE band signals; the transmission coefficient of the signals of the 1.71GHz-2.69GHz frequency band on the band-pass filter 3 is greater than-1 dB until the signals are close to 0, the transmission coefficient of the signals of the 0.81GHz-0.96GHz frequency band is less than-30 dB, and the transmission coefficient of the signals of the 3.3GHz-3.8GHz frequency band is less than-21 dB, so that the requirements of filtering the signals of the 2G frequency band and the 5G frequency band can be met; the transmission coefficient of the 3.3GHz-3.8GHz frequency band signal on the high-pass filter 4 is larger than-1 dB until being close to 0, the transmission coefficient of the 0.81GHz-0.96GHz frequency band signal is smaller than-45 dB, and the transmission coefficient of the 1.71GHz-2.69GHz frequency band signal is smaller than-15 dB, so that the requirements of filtering 2G frequency band signals, 3G frequency band signals and LTE frequency band signals can be met.

The combiner disclosed in this embodiment is applied to a receiving end, for example, and the signals containing multiple frequency bands at the receiving end need to be separated so as to transmit the signals of the frequency bands to corresponding antennas for radiation. For example, a signal including a 2G band, a 5G band, and 3G and LTE bands is input to the combiner from the first port 6, and then transmitted to the low-pass filter 2, the band-pass filter 3, and the high-pass filter 4 via the impedance adjusting section 5, respectively, and each filter filters a signal including a plurality of bands, and finally outputs only a signal of the 2G band from the second port 7, only a signal of the 3G and LTE bands from the third port 8, and only a signal of the 5G band from the fourth port 9. The second port 7 may be connected to a 2G antenna, so as to radiate signals in the 2G frequency band; the third port 8 may be connected to a 3G, LTE antenna to radiate signals in the 3G and LTE bands; the fourth port 9 may be connected to a 5G antenna for radiating signals in the 5G band.

The combiner disclosed in this embodiment can effectively separate and transmit signals including two or three frequency bands, and impedance matching of each frequency band can be realized at the combining end. Each filter can ensure that the transmission coefficient of the frequency band is larger than-1 dB until the transmission coefficient is close to 0, and simultaneously can ensure that the transmission coefficient of signals of other frequency bands is smaller than-15 dB, thereby realizing high-efficiency filtering. In addition, the structural design and the layout method of each filter in the embodiment can effectively avoid the coupling of signals among the filters, and enhance the filtering effect of the combiner.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims

1. The combiner is characterized by comprising a substrate, wherein the substrate comprises a first surface and a second surface which are oppositely arranged, the second surface is covered with copper and grounded, and the first surface is provided with a microstrip line which consists of:

2. The combiner of claim 1, wherein two interdigital microstrip branches are sequentially disposed on the main channel of the low pass filter, such that the transmission coefficient of signals of the 2G band is greater than-1.5 dB thereon, and the transmission coefficients of signals of the 5G band, the 3G band, and the LTE band are less than-15 dB thereon.

3. The combiner of claim 1, wherein the main channel of the band pass filter is sequentially provided with an L-shaped microstrip branch and a circular arc-shaped microstrip branch, so that the transmission coefficients of signals in 3G and LTE bands are greater than-1.5 dB, and the transmission coefficients of signals in 2G and 5G bands are less than-15 dB.

4. The combiner of claim 1, wherein two L-shaped microstrip branches are sequentially disposed on the main channel of the high pass filter, such that a transmission coefficient of a signal of a 5G band is greater than-1.5 dB thereon, and a transmission coefficient of a signal of a 2G band, a 3G band, and an LTE band is less than-15 dB thereon.

5. The combiner of claim 1, wherein two U-shaped microstrip lines with opposite opening directions are sequentially disposed on the main channel of the low pass filter, so that the transmission coefficient of signals in the 2G band is greater than-1.5 dB, and the transmission coefficients of signals in the 5G band, the 3G band and the LTE band are less than-15 dB.

6. The combiner of claim 1, wherein the band-pass filter comprises a plurality of sequentially coupled microstrip lines, two ends of each microstrip line are linear microstrip lines, the middle of each microstrip line is at least two U-shaped microstrip lines, the U-shaped microstrip lines are distributed in an interdigital manner to form an S-shaped or continuous S-shaped structure, so that the transmission coefficients of signals in 3G and LTE frequency bands are larger than-1.5 dB, and the transmission coefficients of signals in 2G and 5G frequency bands are smaller than-15 dB.

7. The combiner of claim 1, wherein the high pass filter is composed of a plurality of microstrip lines distributed in a staircase shape, and adjacent microstrip lines are coupled to each other such that the transmission coefficient of signals in the 5G band is greater than-1.5 dB, and the transmission coefficients of signals in the 2G band, the 3G band and the LTE band are less than-15 dB.

8. The combiner according to any one of claims 1 to 7, wherein the impedance adjusting section includes four microstrip branches communicating with each other, one of which is connected to the first port, and the other three of which are connected to the main channels of the low pass filter, the high pass filter, and the band pass filter, respectively.

9. The combiner according to any of claims 1 to 7, wherein the impedance adjusting section includes three microstrip branches communicating with each other, one of the microstrip branches is connected to the first port, the other two microstrip branches are connected to the low pass filter and the high pass filter, respectively, and one end of the band pass filter is connected to a middle portion of the impedance adjusting section.