CN110994095B - Low-pass filter, millimeter wave AAU system and communication device - Google Patents
Low-pass filter, millimeter wave AAU system and communication device Download PDFInfo
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- CN110994095B CN110994095B CN201911265548.8A CN201911265548A CN110994095B CN 110994095 B CN110994095 B CN 110994095B CN 201911265548 A CN201911265548 A CN 201911265548A CN 110994095 B CN110994095 B CN 110994095B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/201—Filters for transverse electromagnetic waves
- H01P1/203—Strip line filters
- H01P1/20327—Electromagnetic interstage coupling
- H01P1/20354—Non-comb or non-interdigital filters
- H01P1/20381—Special shape resonators
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/02—Transmitters
- H04B1/04—Circuits
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
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- H04B2001/0408—Circuits with power amplifiers
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Abstract
The invention relates to a low-pass filter, a millimeter wave AAU system and a communication device. The low-pass filter comprises a high-low impedance microstrip line low-pass filter structure and coupler branches. The high-low impedance microstrip low-pass filtering structure comprises a plurality of microstrip lines which are folded and are electrically connected in sequence. One end of the coupler branch is used for being electrically connected with the signal detection module, and the other end of the coupler branch is used for being grounded through a matched load. After being connected to the input port of the millimeter wave AIP antenna module, on one hand, the standing wave detection, the power detection, the DPD function and the harmonic wave and out-of-band spurious suppression of the input port signal of the millimeter wave AIP antenna module can be realized; on the other hand, as the microstrip lines of the high-low impedance microstrip line low-pass filter structure are folded, the high-low impedance microstrip line low-pass filter structure is of a miniaturized design, the size of the device is reduced to the greatest extent, the occupied space is small, and the miniaturized design can be realized while the planar circuit interconnection design is facilitated.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a low-pass filter, a millimeter wave AAU system, and a communications device.
Background
Conventionally, a millimeter wave AAU (ACTIVE ANTENNA Unit ) system includes a transmitting end for transmitting an intermediate frequency signal, a local oscillator module, a mixer, a power amplifier, a low pass filter, and a millimeter wave AIP antenna module. The transmitting end transmits the intermediate frequency signal to the mixer, the mixer carries out mixed up-conversion on the intermediate frequency signal and the local oscillation signal transmitted by the local oscillation module, then the mixed up-conversion is transmitted to the power amplifier, the power amplifier amplifies the signal and transmits the amplified signal to the low-pass filter, and the low-pass filter carries out signal harmonic and spurious suppression processing on the signal transmitted by the power amplifier and transmits the signal to the millimeter wave AIP antenna module. In conventional designs, the low pass filter and coupler are often two separate devices, the link size length being the sum of the two. In order to save space and reduce loss, a conventional high-power low-loss coupling filter generally adopts a cascade connection mode of a dual directional coupler and a band-pass filter, and the design of the filter with the coupler is mainly realized through a cavity structure. However, a miniaturized design cannot be achieved.
Disclosure of Invention
Based on this, it is necessary to overcome the defects of the prior art, and to provide a low-pass filter, a millimeter wave AAU system and a communication device, which can realize a miniaturized design.
The technical scheme is as follows: a low pass filter, comprising: the high-low impedance microstrip low-pass filter structure comprises a plurality of microstrip lines which are folded and are electrically connected in sequence, wherein the head end microstrip line at the head end part of the microstrip lines is used for being connected with the output end of the power amplifier, and the tail end microstrip line at the tail end part of the microstrip lines is used for being electrically connected with the millimeter wave AIP antenna module; and the coupler branch comprises a plurality of transmission lines which are electrically connected in sequence, the coupler branch and the high-low impedance microstrip line low-pass filtering structure are arranged at intervals and are mutually coupled and matched, the coupler branch is matched with a head end microstrip line at the head end part and a tail end microstrip line at the tail end part to form a directional coupler, one end of the coupler branch is electrically connected with the signal detection module, and the other end of the coupler branch is grounded through a matched load.
After the low-pass filter is connected to the input port of the millimeter wave AIP (ANTENNA IN PACKAGE, packaged antenna) antenna module, on one hand, standing wave detection, power detection, DPD (digital predistortion) function and harmonic and out-of-band spurious suppression of input port signals of the millimeter wave AIP antenna module can be realized, and on the other hand, as a plurality of microstrip lines of the high-low impedance microstrip line low-pass filter structure are folded, the high-low impedance microstrip line low-pass filter structure is in a miniaturized design, the size of a device is reduced to the greatest extent, the occupied space is small, and the miniaturized design can be realized while the planar circuit interconnection design is facilitated.
In one embodiment, the microstrip line includes a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a head-end microstrip line, and a tail-end microstrip line; the first microstrip line, the second microstrip line, the third microstrip line, the fourth microstrip line and the fifth microstrip line are electrically connected in sequence; the arrangement directions of the first microstrip line and the second microstrip line are the same, and the arrangement directions of the fourth microstrip line and the fifth microstrip line are the same; the first microstrip line and the fourth microstrip line are arranged at parallel intervals, and the second microstrip line and the fifth microstrip line are arranged at parallel intervals; the first microstrip line is electrically connected with the signal input module through the head end microstrip line, and the fifth microstrip line is electrically connected with the millimeter wave AIP antenna module through the tail end microstrip line.
In one embodiment, the setting direction of the first microstrip line is perpendicular to the setting direction of the first microstrip line and the setting direction of the second microstrip line, the setting direction of the first microstrip line is perpendicular to the setting direction of the third microstrip line, and the setting direction of the first microstrip line is parallel to the setting direction of the fourth microstrip line.
In one embodiment, the length L6 of the head-end microstrip line is the same as the length L7 of the tail-end microstrip line; the width W6 of the head-end microstrip line is the same as the width W7 of the tail-end microstrip line.
In one embodiment, a straight line passing through a center point of the third microstrip line and perpendicular to the third microstrip line is defined as a symmetry axis P, and the high-low impedance microstrip line low-pass filter structure is axisymmetrically disposed about the symmetry axis P.
In one embodiment, the length L1 of the first microstrip line is 3.4 mm-4.2 mm, and the width W1 is 2 mm-2.8 mm; the length L2 of the second microstrip line is 2.5-3.3 mm, and the width W2 is 0.1-0.3 mm; the length L3 of the third microstrip line is 6.4-7.2 mm, and the width W3 is 2-2.8 mm; the length L4 of the fourth microstrip line is 2.5 mm-3.3 mm, and the width W4 is 0.1 mm-0.3 mm; the length L5 of the fifth microstrip line is 3.4-4.2 mm, and the width W5 is 2-2.8 mm; the length L6 of the head-end microstrip line is 1.5 mm-2.5 mm, and the width W6 is 0.9 mm-1.3 mm; the length L7 of the tail end microstrip line is 1.5 mm-2.5 mm, and the width W7 is 0.9 mm-1.3 mm.
In one embodiment, one end of the head-end microstrip line connected with the first microstrip line is a tapered section with a width gradually decreasing towards a direction close to the first microstrip line; and one end of the tail end microstrip line connected with the fifth microstrip line is a tapered section with the width gradually becoming smaller towards the direction close to the fifth microstrip line.
In one embodiment, the coupler knuckle includes a first transmission line and two second transmission lines; the first transmission line and the high-low impedance microstrip line low-pass filtering structure are arranged at intervals, and a plurality of teeth at intervals are arranged on one side of the first transmission line facing the high-low impedance microstrip line low-pass filtering structure; the two second transmission lines are respectively connected with two ends of the first transmission line.
In one embodiment, the second transmission line includes a first split section and a second split section; one end of the first split section is connected with the first transmission line, the other end of the first split section is connected with the second split section, the width of the first split section is smaller than that of the second split section, and one end of the second split section connected with the first split section is a gradual change section with the width gradually becoming smaller towards the direction close to the first split section.
In one embodiment, the teeth are triangular, square or semicircular in shape; the interval S between adjacent tooth parts is 0.12 mm-0.18 mm, the height h of the tooth parts is 0.4 mm-0.8 mm, and the width a of the tooth parts is 0.4 mm-1.2 mm.
The millimeter wave AAU system comprises the low-pass filter, a transmitting end for transmitting intermediate frequency signals, a local oscillator module, a mixer, a power amplifier, a signal detection module and a millimeter wave AIP antenna module; the transmitting end and the local oscillator module are both connected with the input end of the mixer, the output end of the mixer is connected with the input end of the power amplifier, the output end of the power amplifier is connected with the head-end microstrip line, and the input port of the millimeter wave AIP antenna module is connected with the tail-end microstrip line; one end of the coupler branch is electrically connected with the signal detection module, and the other end of the coupler branch is grounded through a matched load.
After the millimeter wave AAU system is connected to the input port of the millimeter wave AIP (ANTENNA IN PACKAGE, package antenna) antenna module, on one hand, standing wave detection, power detection, DPD (digital predistortion) function and harmonic and out-of-band spurious suppression of input port signals of the millimeter wave AIP antenna module can be realized, and on the other hand, as a plurality of microstrip lines of the high-low impedance microstrip line low-pass filter structure are folded, the high-low impedance microstrip line low-pass filter structure is in a miniaturized design, the size of a device is reduced to the greatest extent, the occupied space is small, and the miniaturized design can be realized while the planar circuit interconnection design is facilitated.
A communication device comprising said low pass filter.
After the communication device is connected to the input port of the millimeter wave AIP (ANTENNA IN PACKAGE, packaged antenna) antenna module, on one hand, the standing wave detection, the power detection, the DPD (digital predistortion) function and the harmonic and out-of-band spurious suppression of input port signals of the millimeter wave AIP antenna module can be realized, and on the other hand, as a plurality of microstrip lines of the high-low impedance microstrip line low-pass filter structure are folded, the high-low impedance microstrip line low-pass filter structure is of a miniaturized design, the size of a device is reduced to the greatest extent, the occupied space is small, and the miniaturized design can be realized while the planar circuit interconnection design is facilitated.
Drawings
Fig. 1 is a schematic diagram of a low-pass filter according to an embodiment of the invention;
Fig. 2 is a schematic structural diagram of a low-pass filter according to another embodiment of the present invention;
fig. 3 is a schematic structural diagram of a millimeter wave AAU system according to an embodiment of the present invention;
FIG. 4 is a simulation plot of insertion loss, return loss, and out-of-band rejection of a low pass filter in accordance with an embodiment of the present invention;
Fig. 5 is a simulation plot of coupling and isolation of coupler stubs in a low pass filter in accordance with an embodiment of the present invention.
Reference numerals:
100. A low pass filter; 110. a high-low impedance microstrip line low-pass filtering structure; 111. a first microstrip line; 112. a second microstrip line; 113. a third microstrip line; 114. a fourth microstrip line; 115. a fifth microstrip line; 116. a head end microstrip line; 1161. a first oblique side; 117. a terminal microstrip line; 1171. a second oblique side; 120. coupler knuckles; 121. a first transmission line; 1211. a tooth portion; 122. a second transmission line; 1221. a first split section; 1222. a second segment; 1223. a third oblique side; 200. a transmitting end; 300. a local oscillation module; 400. a mixer; 500. a power amplifier; 600. a signal detection module; 610. a digital-to-analog conversion module; 620. a digital signal processing module; 700. a millimeter wave AIP antenna module; 800. and a circuit control module.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.
In the description of the present invention, it should be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the description of the present invention, it will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly connected" to another element, there are no intervening elements present.
In one embodiment, referring to fig. 1 to 3, a low-pass filter 100 includes a high-low impedance microstrip low-pass filter structure 110 and a coupler stub 120. The high-low impedance microstrip low-pass filter structure 110 includes a plurality of microstrip lines which are folded and electrically connected in sequence. The head-end microstrip line 116 at the head-end part of the microstrip lines is used for being connected with the output end of the power amplifier 500, and the tail-end microstrip line 117 at the tail-end part of the microstrip lines is used for being electrically connected with the millimeter wave AIP antenna module 700. The coupler branch 120 comprises a plurality of transmission lines electrically connected in sequence, the coupler branch 120 and the high-low impedance microstrip low-pass filter structure 110 are arranged at intervals and are mutually coupled and matched, the coupler branch 120 is matched with the head-end microstrip line 116 at the head-end part and the tail-end microstrip line 117 at the tail-end part to form a directional coupler, one end of the coupler branch 120 is electrically connected with the signal detection module 600, and the other end of the coupler branch 120 is grounded through a matched load.
After the low-pass filter 100 is connected to the input port of the millimeter wave AIP (ANTENNA IN PACKAGE, package antenna) antenna module, on one hand, the standing wave detection, the power detection, the DPD (DIGITAL PRE-Distortion) function, and the harmonic and out-of-band spurious suppression of the input port signal of the millimeter wave AIP antenna module 700 can be realized, and on the other hand, since the multiple microstrip lines of the high-low impedance microstrip line low-pass filter structure 110 are folded, the high-low impedance microstrip line low-pass filter structure 110 is designed in a miniaturized manner, the size of the device is reduced to the greatest extent, the occupied space is small, and the miniaturization design can be realized while the planar circuit interconnection design is facilitated.
Further, the microstrip lines include a first microstrip line 111, a second microstrip line 112, a third microstrip line 113, a fourth microstrip line 114, a fifth microstrip line 115, a head-end microstrip line 116, and an end microstrip line 117. The first microstrip line 111, the second microstrip line 112, the third microstrip line 113, the fourth microstrip line 114, and the fifth microstrip line 115 are electrically connected in sequence. The first microstrip line 111 and the second microstrip line 112 are arranged in the same direction, and the fourth microstrip line 114 and the fifth microstrip line 115 are arranged in the same direction. The first microstrip line 111 and the fourth microstrip line 114 are arranged at a parallel interval, and the second microstrip line 112 and the fifth microstrip line 115 are arranged at a parallel interval. The first microstrip line 111 is electrically connected to the signal input module through the head-end microstrip line 116, and the fifth microstrip line 115 is electrically connected to the millimeter wave AIP antenna module 700 through the tail-end microstrip line 117. The first microstrip line 111, the second microstrip line 112, the third microstrip line 113, the fourth microstrip line 114 and the fifth microstrip line 115 are equivalent to a five-order low-pass filter, and can pass below a preset cut-off frequency, so as to inhibit and filter signals above the cut-off frequency. For the fifth-order low-pass filter, the first-end microstrip line 116 and the tail-end microstrip line 117 are both equivalent to function as electrical connection, and the first-end microstrip line 116 is electrically connected to the output end of the power amplifier 500 to introduce a transmission signal into the fifth-order low-pass filter; the terminal microstrip line 117 is electrically connected to the input port of the millimeter wave AIP antenna module 700, and transmits a clean, stable, high-quality transmission signal to the millimeter wave AIP antenna module 700. Of course, the high-low impedance microstrip low-pass filter structure 110 is not limited to be designed as a five-order low-pass filter, and may be designed as a low-pass filter of other orders.
Referring to fig. 1 or fig. 2, the folding manner of the low-pass filter structure 110 of the high-low impedance microstrip line may specifically be: the arrangement direction of the first microstrip line 111 is perpendicular to the arrangement direction of the head-end microstrip line 116 and the arrangement direction of the tail-end microstrip line 117, the arrangement direction of the first microstrip line 111 is perpendicular to the arrangement direction of the third microstrip line 113, and the arrangement direction of the first microstrip line 111 is parallel to the arrangement direction of the fourth microstrip line 114. Thus, on one hand, the performance of the high-low impedance microstrip line low-pass filter structure 110 can be ensured, and on the other hand, the miniaturization design of the device can be realized, and the volume size and the occupied space can be reduced.
As an alternative, the included angle between the arrangement direction of the first microstrip line 111 and the arrangement direction of the head-end microstrip line 116 and the arrangement direction of the tail-end microstrip line 117 is, for example, in the range of 60 degrees to 120 degrees.
As an alternative, the angle between the arrangement direction of the first microstrip line 111 and the arrangement direction of the third microstrip line 113 is, for example, in the range of 0 degrees to 30 degrees.
In one embodiment, the length L6 of the head-end microstrip line 116 is the same as the length L7 of the tail-end microstrip line 117. The width W6 of the head microstrip line 116 is the same as the width W7 of the tail microstrip line 117.
In one embodiment, a straight line passing through the center point of the third microstrip line 113 and perpendicular to the third microstrip line 113 is defined as a symmetry axis P, and the high-low impedance microstrip line low-pass filter structure 110 is axisymmetrically disposed about the symmetry axis P.
In one embodiment, the length L1 of the first microstrip line 111 is 3.4mm to 4.2mm, and the width W1 is 2mm to 2.8mm; the length L2 of the second microstrip line 112 is 2.5 mm-3.3 mm, and the width W2 is 0.1 mm-0.3 mm; the length L3 of the third microstrip line 113 is 6.4 mm-7.2 mm, and the width W3 is 2 mm-2.8 mm; the length L4 of the fourth microstrip line 114 is 2.5 mm-3.3 mm, and the width W4 is 0.1 mm-0.3 mm; the length L5 of the fifth microstrip line 115 is 3.4 mm-4.2 mm, and the width W5 is 2 mm-2.8 mm; the length L6 of the head-end microstrip line 116 is 1.5 mm-2.5 mm, and the width W6 is 0.9 mm-1.3 mm; the length L7 of the terminal microstrip line 117 is 1.5mm to 2.5mm, and the width W7 is 0.9mm to 1.3mm.
Specifically, the head microstrip line 116 and the tail microstrip line 117 are, for example, 50Ω impedance microstrip lines.
Specifically, the length L1 of the first microstrip line 111 is 3.8mm, and the width W1 is 2.4mm; the length L2 of the second microstrip line 112 is 2.9mm, and the width W2 is 0.2mm; the length L3 of the third microstrip line 113 is 6.8mm, and the width W3 is 2.4mm; the length L4 of the fourth microstrip line 114 is 2.9mm, and the width W4 is 0.2mm; the length L5 of the fifth microstrip line 115 is 3.8mm, and the width W5 is 2.4mm; the length L6 of the head-end microstrip line 116 is 2mm, and the width W6 is 1.1mm; the length L7 of the end microstrip line 117 is 2mm, and the width W7 is 1.1mm.
In one embodiment, referring to fig. 1 and 2, an end of the head microstrip line 116 connected to the first microstrip line 111 is a tapered section with a width gradually decreasing toward a direction approaching the first microstrip line 111. Specifically, a side portion of one end of the head-end microstrip line 116 connected to the first microstrip line 111 is provided with a first oblique side 1161. In this way, a better feeding of the signal on the head-end microstrip line 116 to the first microstrip line 111 can be achieved.
Further, as such, the end of the end microstrip line 117 connected to the fifth microstrip line 115 is a tapered section whose width gradually becomes smaller toward the direction closer to the fifth microstrip line 115. Specifically, the side portion of the end microstrip line 117 connected to the fifth microstrip line 115 is provided with a second oblique side 1171. In this way, a better feed transmission of the signal on the fifth microstrip line 115 to the end microstrip line 117 can be achieved.
In one embodiment, the coupler knuckle 120 includes a first transmission line 121 and two second transmission lines 122. The first transmission line 121 is spaced from the low-pass filter structure 110, and a plurality of spaced teeth 1211 are disposed on a side of the first transmission line 121 facing the low-pass filter structure 110. Two second transmission lines 122 are connected to both ends of the first transmission line 121, respectively. In this way, under the action of the plurality of teeth 1211 of the first transmission line 121, the difference of the phase velocities of the odd coupling modes of the microstrip coupling transmission line can be effectively reduced, and the directivity of the directional coupler can be greatly improved.
Specifically, the first transmission line 121 and the third microstrip line 113 are arranged in parallel at an interval. In this way, when the low-pass filter 100 needs to have both the power detection function and the standing wave detection function, it is advantageous to realize that the shape and size of the head-end microstrip line 116 are the same as the shape and size of the tail-end microstrip line 117. Of course, as an alternative, the first transmission line 121 may be disposed at a parallel interval with the end microstrip line 117, and in this case, in order to implement the low-pass filter 100 with both the power detection function and the standing wave detection function, the length of the end microstrip line 117 is generally greater than that of the head microstrip line 116, so that the overall size is greater than that of the first transmission line 121 and the third microstrip line 113 disposed at a parallel interval.
In one embodiment, the second transmission line 122 includes a first split section 1221 and a second split section 1222. One end of the first split section 1221 is connected to the first transmission line 121, the other end of the first split section 1221 is connected to the second split section 1222, the width of the first split section 1221 is smaller than that of the second split section 1222, and the end of the second split section 1222 connected to the first split section 1221 is a gradual change section with a width gradually decreasing toward a direction close to the first split section 1221. Specifically, a side portion of one end of the second split section 1222 connected to the first split section 1221 is provided with a third slope 1223. Thus, on the one hand, the first split section 1221 can be matched to the impedance of the second split section 1222, and on the other hand, the transmission signal on the first split section 1221 can be smoothly transmitted to the second split section 1222.
In one embodiment, the teeth 1211 are triangular, square, or semi-circular in shape.
In one embodiment, the spacing S between adjacent teeth 1211 is 0.12mm to 0.18mm, the height h of the teeth 1211 is 0.4mm to 0.8mm, and the width a of the teeth 1211 is 0.4mm to 1.2mm.
Specifically, the space S between adjacent teeth 1211 is 0.15mm, the height h of the teeth 1211 is 0.6mm, and the width a of the teeth 1211 is 0.8mm.
In one embodiment, referring to fig. 1 to 3, a millimeter wave AAU system includes the low-pass filter 100 according to any one of the above embodiments, and further includes a transmitting end 200 for transmitting an intermediate frequency signal, a local oscillation module 300, a mixer 400, a power amplifier 500, a signal detection module 600, and a millimeter wave AIP antenna module 700. The transmitting end 200 and the local oscillator module 300 are both connected with the input end of the mixer 400, the output end of the mixer 400 is connected with the input end of the power amplifier 500, the output end of the power amplifier 500 is connected with the head-end microstrip line 116, and the input port of the millimeter wave AIP antenna module 700 is connected with the tail-end microstrip line 117. One end of the coupler knuckle 120 is electrically connected to the signal detection module 600, and the other end of the coupler knuckle 120 is grounded through a matching load.
After the millimeter wave AAU system is connected to the input port of the millimeter wave AIP (ANTENNA IN PACKAGE, package antenna) antenna module, on one hand, the standing wave detection, the power detection, the DPD (DIGITAL PRE-Distortion) function, and the harmonic and out-of-band spurious suppression of the input port signal of the millimeter wave AIP antenna module 700 can be realized, and on the other hand, since the multiple microstrip lines of the high-low impedance microstrip line low-pass filter structure 110 are folded, the high-low impedance microstrip line low-pass filter structure 110 is in a miniaturized design, the size of the device is reduced to the greatest extent, the occupied space is small, and the miniaturized design can be realized while the planar circuit interconnection design is facilitated. In addition, the low-pass filter 100 of the above embodiment performs the functions of signal harmonic and spurious suppression, power detection, standing wave detection and DPD, and can provide clean, stable and high-quality input signals for the rear millimeter wave AIP module.
Further, the signal detection module 600 includes a digital-to-analog conversion module 610 and a digital signal processing module 620. One end of the coupler knuckle 120 is connected to a digital-to-analog conversion processing module, which is connected to a digital signal processing module 620.
Further, the millimeter wave AAU system also includes a circuit control module 800. The coupler knuckle 120 is connected to the digital-to-analog conversion processing module through the circuit control module 800.
When the power detection state needs to be adjusted, the circuit control module 800 switches to the first working state, so as to control the second transmission line 122 close to the head-end microstrip line 116 to be connected with the digital-to-analog conversion processing module, and the other second transmission line 122 is connected with a resistor of, for example, 50Ω and then grounded, at this time, the second transmission line 122 close to the head-end microstrip line 116 is coupled with the head-end microstrip line 116, the head-end microstrip line 116 not only filters the transmission signal through the five-order low-pass filter and then transmits the filtered transmission signal to the millimeter wave AIP antenna module 700, the head-end microstrip line 116 also transmits the transmission signal to the second transmission line 122 close to the head-end microstrip line 116 in a coupling manner, and then the second transmission line 122 close to the head-end microstrip line 116 transmits the transmission signal to the signal detection module 600, and the signal detection module 600 can correspondingly realize the function of power detection. At this time, the other second transmission line 122 is grounded after being connected to a matching resistor of, for example, 50Ω, so that the impedance of the second transmission line 122 can be matched, and the interference effect of the idle second transmission line 122 on the other three ports is avoided.
When the standing wave detection state needs to be adjusted, the circuit control module 800 switches to the second working state, so as to control the second transmission line 122 close to the end microstrip line 117 to be connected with the digital-to-analog conversion processing module, and the other second transmission line 122 is connected with a resistor of, for example, 50Ω and then grounded, at this time, the second transmission line 122 close to the end microstrip line 117 and the head-end microstrip line 116 are coupled with each other, the end microstrip line 117 can transmit the standing wave signal of the millimeter wave AIP antenna module 700 to the second transmission line 122 close to the end microstrip line 117, and then the second transmission line 122 close to the end microstrip line 117 sends the standing wave signal to the signal detection module 600, and the signal detection module 600 can correspondingly realize the function of standing wave detection. Similarly, since the other second transmission line 122 is grounded after being connected to a resistor of 50Ω, the impedance of the second transmission line 122 can be matched, so as to avoid the interference effect of the idle second transmission line 122 on the other three ports.
In one embodiment, a communication device includes the low pass filter 100 of any of the embodiments described above.
After the communication device is connected to the input port of the millimeter wave AIP (ANTENNA IN PACKAGE, package antenna) antenna module, on one hand, the standing wave detection, the power detection, the DPD (DIGITAL PRE-Distortion) function and the harmonic and out-of-band spurious suppression of the input port signal of the millimeter wave AIP antenna module 700 can be realized, and on the other hand, since the microstrip lines of the high-low impedance microstrip line low-pass filter structure 110 are folded, the high-low impedance microstrip line low-pass filter structure 110 is in a miniaturized design, the size of the device is reduced to the greatest extent, the occupied space is small, and the miniaturized design can be realized while the planar circuit interconnection design is facilitated.
Referring to fig. 4 and 5, fig. 4 is a simulation curve of insertion loss, return loss and out-of-band rejection of the low pass filter 100 according to the present embodiment. As can be seen from fig. 4, when the frequency point of the signal is 3.6GHz, the insertion loss is about 0.25dB, and the second harmonic suppression is greater than 19dB, thereby satisfying the design expectation. Fig. 5 is a coupling degree and isolation degree simulation curve of the coupler knuckle 120 in the low-pass filter 100 of the present embodiment. As can be seen from fig. 5, the interpolation loss is about 1.4dB in the 800MHz bandwidth (2.8 GHz-3.6 GHz), and the directivity is greater than 23dB (directivity=isolation-coupling degree), satisfying the design expectations.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (11)
1. A low pass filter, comprising:
The high-low impedance microstrip low-pass filtering structure comprises a plurality of microstrip lines which are folded and electrically connected in sequence, wherein each microstrip line comprises a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a head-end microstrip line and a tail-end microstrip line; the first microstrip line, the second microstrip line, the third microstrip line, the fourth microstrip line and the fifth microstrip line are electrically connected in sequence; the first microstrip line and the fourth microstrip line are arranged at parallel intervals, and the second microstrip line and the fifth microstrip line are arranged at parallel intervals; the first microstrip line is electrically connected with the output end of the power amplifier through the head end microstrip line, and the fifth microstrip line is electrically connected with the millimeter wave AIP antenna module through the tail end microstrip line; and
The coupler branch comprises a plurality of transmission lines which are electrically connected in sequence, the coupler branch and the high-low impedance microstrip line low-pass filtering structure are arranged at intervals and are mutually coupled and matched, the coupler branch is matched with a head-end microstrip line at a head-end part and a tail-end microstrip line at a tail-end part to form a directional coupler, one end of the coupler branch is used for being electrically connected with the signal detection module, and the other end of the coupler branch is used for being grounded through a matched load; the coupler knuckle comprises a first transmission line and two second transmission lines; the first transmission line and the high-low impedance microstrip line low-pass filtering structure are arranged at intervals, and a plurality of teeth at intervals are arranged on one side of the first transmission line facing the high-low impedance microstrip line low-pass filtering structure; the two second transmission lines are respectively connected with two ends of the first transmission line.
2. The low-pass filter according to claim 1, wherein the first microstrip line and the second microstrip line are arranged in the same direction, and the fourth microstrip line and the fifth microstrip line are arranged in the same direction.
3. The low-pass filter according to claim 2, wherein the arrangement direction of the first microstrip line is perpendicular to the arrangement direction of the head-end microstrip line and the arrangement direction of the tail-end microstrip line, respectively, the arrangement direction of the first microstrip line is perpendicular to the arrangement direction of the third microstrip line, and the arrangement direction of the first microstrip line is parallel to the arrangement direction of the fourth microstrip line.
4. The low-pass filter according to claim 2, wherein the length L6 of the head-end microstrip line is the same as the length L7 of the tail-end microstrip line; the width W6 of the head-end microstrip line is the same as the width W7 of the tail-end microstrip line.
5. The low-pass filter according to claim 2, characterized in that a straight line passing through a center point of the third microstrip line and perpendicular to the third microstrip line is defined as a symmetry axis P, and the high-low impedance microstrip line low-pass filter structure is axisymmetrically disposed about the symmetry axis P.
6. The low-pass filter according to claim 2, wherein the length L1 of the first microstrip line is 3.4mm to 4.2mm, and the width W1 is 2mm to 2.8mm; the length L2 of the second microstrip line is 2.5 mm-3.3 mm, and the width W2 is 0.1 mm-0.3 mm; the length L3 of the third microstrip line is 6.4 mm-7.2 mm, and the width W3 is 2-2.8 mm; the length L4 of the fourth microstrip line is 2.5 mm-3.3 mm, and the width W4 is 0.1 mm-0.3 mm; the length L5 of the fifth microstrip line is 3.4-4.2 mm, and the width W5 is 2-2.8 mm; the length L6 of the head-end microstrip line is 1.5 mm-2.5 mm, and the width W6 is 0.9 mm-1.3 mm; the length L7 of the tail end microstrip line is 1.5 mm-2.5 mm, and the width W7 is 0.9 mm-1.3 mm.
7. The low-pass filter according to claim 2, wherein an end of the head-end microstrip line connected to the first microstrip line is a tapered section having a width gradually decreasing toward a direction approaching the first microstrip line; and one end of the tail end microstrip line connected with the fifth microstrip line is a tapered section with the width gradually becoming smaller towards the direction close to the fifth microstrip line.
8. The low pass filter of claim 1, wherein the second transmission line comprises a first split section and a second split section; one end of the first split section is connected with the first transmission line, the other end of the first split section is connected with the second split section, the width of the first split section is smaller than that of the second split section, and one end of the second split section connected with the first split section is a gradual change section with the width gradually becoming smaller towards the direction close to the first split section.
9. The low pass filter of claim 1, wherein the teeth are triangular, square or semi-circular in shape; the interval S between adjacent teeth is 0.12 mm-0.18 mm, the height h of the teeth is 0.4-0.8 mm, and the width a of the teeth is 0.4-mm-1.2 mm.
10. A millimeter wave AAU system, comprising the low-pass filter of any one of claims 1 to 9, further comprising a transmitting end for transmitting an intermediate frequency signal, a local oscillator module, a mixer, a power amplifier, a signal detection module, and a millimeter wave AIP antenna module; the transmitting end and the local oscillator module are both connected with the input end of the mixer, the output end of the mixer is connected with the input end of the power amplifier, the output end of the power amplifier is connected with the head-end microstrip line, and the input port of the millimeter wave AIP antenna module is connected with the tail-end microstrip line; one end of the coupler branch is electrically connected with the signal detection module, and the other end of the coupler branch is grounded through a matched load.
11. A communication device comprising a low pass filter according to any of claims 1 to 9.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102394385A (en) * | 2011-06-30 | 2012-03-28 | 陕西黄河集团有限公司 | Large-wide-angle low-standing-wave microstrip frequency sweep antenna based on suspended strip slow-wave line |
| CN104953225A (en) * | 2015-05-29 | 2015-09-30 | 南通大学 | Balance-type branch line coupler with filter function |
| CN104993205A (en) * | 2015-07-06 | 2015-10-21 | 电子科技大学 | Microstrip fold line directional coupler |
| CN105098303A (en) * | 2015-08-25 | 2015-11-25 | 华南理工大学 | Power divider with double-band filter function |
| CN110444840A (en) * | 2019-08-06 | 2019-11-12 | 西安电子科技大学 | Double frequency differential bandpass filter based on minor matters Load resonators |
| CN211125950U (en) * | 2019-12-11 | 2020-07-28 | 京信通信技术(广州)有限公司 | Low pass filter, millimeter wave AAU system and communication device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3474443B1 (en) * | 2017-10-18 | 2021-03-10 | NXP USA, Inc. | Amplifier power combiner with slotline impedance transformer |
-
2019
- 2019-12-11 CN CN201911265548.8A patent/CN110994095B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102394385A (en) * | 2011-06-30 | 2012-03-28 | 陕西黄河集团有限公司 | Large-wide-angle low-standing-wave microstrip frequency sweep antenna based on suspended strip slow-wave line |
| CN104953225A (en) * | 2015-05-29 | 2015-09-30 | 南通大学 | Balance-type branch line coupler with filter function |
| CN104993205A (en) * | 2015-07-06 | 2015-10-21 | 电子科技大学 | Microstrip fold line directional coupler |
| CN105098303A (en) * | 2015-08-25 | 2015-11-25 | 华南理工大学 | Power divider with double-band filter function |
| CN110444840A (en) * | 2019-08-06 | 2019-11-12 | 西安电子科技大学 | Double frequency differential bandpass filter based on minor matters Load resonators |
| CN211125950U (en) * | 2019-12-11 | 2020-07-28 | 京信通信技术(广州)有限公司 | Low pass filter, millimeter wave AAU system and communication device |
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