A radio frequency switching printed board

Abstract

The application discloses a radio frequency switching printed board, which comprises a printed board, radio frequency connectors arranged on both sides of the printed board, the radio frequency connectors on both sides are radio frequency connector I and radio frequency connector II respectively, the radio frequency connectors on both sides are one-to-one corresponding and are connected in communication with each other, the radio frequency connector I is used for plugging with an antenna unit, and the radio frequency connector II on the other side is used for plugging with a transceiving assembly. Compared with the prior art, the radio frequency switching printed board is installed at the rear end of the antenna unit and is located between the antenna unit and the transceiving assembly, high-density radio frequency interconnection between the antenna unit and the transceiving assembly is realized, the distance between the antenna array surface and the transceiving assembly is greatly reduced, a large number of radio frequency cables are saved, the weight is reduced, and the assembly and maintenance difficulty are reduced.

Description

Technical Field

[0001] This invention belongs to the field of antenna communication technology, and specifically relates to a radio frequency adapter printed circuit board. Background Technology

[0002] The antenna elements and transceiver components (T / R components) in the antenna array are interconnected through a large number of radio frequency cables; among them, the radio frequency connectors on the antenna surface are interconnected with the antenna modules using isolated radio frequency connectors, while the transceiver component surface uses integrated connectors to achieve blind mating.

[0003] Traditional radar antennas and transceiver components are vertically interconnected via radio frequency (RF) cables. However, as the distance between the antenna array and the transceiver components continues to shrink, RF cables cannot be installed between the radar antenna and the transceiver components, and their weight cannot meet the requirements for miniaturization of weaponry. RF cables also bring problems such as complex assembly and difficult maintenance. Summary of the Invention

[0004] To address the technical problems of miniaturization, complex assembly, and difficult maintenance associated with interconnecting antennas and transceiver components via RF cables, this invention provides an RF adapter printed circuit board.

[0005] The objective of this invention is achieved through the following technical solution. According to this invention, a radio frequency (RF) adapter printed circuit board includes a printed circuit board with RF connectors on both sides. The RF connectors on both sides are RF connector I and RF connector II, respectively. The RF connectors on both sides correspond one-to-one and are communicatively connected to each other. RF connector I is used to connect to an antenna unit, and RF connector II on the other side is used to connect to a transceiver component.

[0006] Furthermore, a fixing plate is attached to both sides of the printed circuit board. The fixing plate has through holes corresponding to the positions of the RF connectors. The tail end of the RF connector is soldered to the printed circuit board, and the plug end is located in the through hole.

[0007] Furthermore, the surface of the fixing plate that mates with the transceiver assembly is provided with guide pins for guiding the installation of the transceiver assembly, and the surface that mates with the antenna unit is provided with antenna mounting holes for installing the antenna unit.

[0008] Furthermore, the RF connectors on the printed circuit board are connected to the RF connectors on the corresponding antenna units and the RF connectors on the transceiver components via adapters.

[0009] Furthermore, the printed circuit board, from top to bottom, consists of solder mask layer I, top layer, ground layer I, RF layer, ground layer II, bottom layer, and solder mask layer II. A prepreg is disposed between the top layer and ground layer I, a core board is disposed between ground layer I and RF layer, a prepreg and a core board are disposed between RF layer and ground layer II, and a prepreg is disposed between ground layer II and bottom layer. The printed circuit board has ground vias and signal vias corresponding to RF connectors. The signal vias include signal via I connected to RF connector I and signal via II connected to RF connector II. The through-layer of signal via I is solder mask layer I, top layer, ground layer I, and RF layer, and the through-layer of signal via II is solder mask layer II, bottom layer, ground layer II, and RF layer. The RF layer has striplines for connecting corresponding signal vias I and II. The through-layer of the ground vias is solder mask layer I, top layer, ground layer I, RF layer, ground layer II, bottom layer, and solder mask layer II. Ground vias are distributed on both sides of the striplines and around the signal vias.

[0010] Furthermore, the thickness of the printed circuit board is 2-3.7mm, and 1-2 additional ground layers are added between the top layer and ground layer I, and between the bottom layer and ground layer II, with corresponding media provided between the additional ground layers.

[0011] Furthermore, the signal via I is processed as a blind via, filled with copper paste, and plated flat; the signal via II is processed as a back drill, filled with copper paste, and plated flat; and the ground via is processed as a through hole and filled with copper paste.

[0012] Furthermore, the signal via I is provided with an inner layer pad I and an inner layer anti-pad I located on the radio frequency layer, and a surface layer pad and a surface layer anti-pad I located on the top layer; the signal via II is provided with an inner layer pad II and an inner layer anti-pad II located on the radio frequency layer, and a surface layer pad II and a surface layer anti-pad II located on the bottom layer, and the signal via II also includes a short post; the ground via is provided with a ground pad on the surface of the printed circuit board.

[0013] Furthermore, the RF connector I and RF connector II are SSMP, SMA or SMP series connectors.

[0014] Furthermore, the drilling diameter of signal via I ranges from 0.25mm to 0.35mm, the diameter of inner layer pad I of signal via I ranges from 0.45mm to 0.65mm, the diameter of inner layer anti-pad I ranges from 1mm to 1.3mm, the short post is 0mm, the diameter of surface pad I is 0.8mm, and the diameter of surface layer anti-pad I ranges from 2mm to 2.4mm; the drilling diameter of signal via II ranges from 0.25mm to 0.35mm, and the diameter of inner layer pad II of signal via II ranges from 0.45mm to 0.6mm. The inner anti-pad II diameter ranges from 1 to 1.3 mm, the short post is 0.15 mm, the surface pad II diameter is 0.8 mm, and the surface anti-pad II diameter ranges from 2 mm to 2.4 mm; the ground pads on the surface of the printed circuit board have a diameter range of 4.8 mm to 5.1 mm; ground holes are distributed on both sides of the stripline, and the spacing between the centers of the corresponding ground holes on both sides of the stripline ranges from 0.65 mm to 0.75 mm; multiple ground holes are distributed around the signal vias, and the spacing between the center of the signal via and the center of the corresponding ground hole ranges from 1.1 mm to 1.45 mm.

[0015] Compared with the prior art, the advantages of the present invention are: the adapter board is installed at the rear end of the antenna unit, between the antenna unit and the transceiver assembly, realizing high-density radio frequency interconnection between the antenna unit and the transceiver assembly, greatly reducing the distance between the antenna array and the transceiver assembly, saving a lot of radio frequency cables, while reducing weight and reducing assembly and maintenance difficulty.

[0016] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0017] Figure 1 This is an overall block diagram showing the connection between the antenna unit and the transceiver assembly in an embodiment of the present invention;

[0018] Figure 2 This is an exploded view of the antenna unit and transceiver components according to an embodiment of the present invention;

[0019] Figure 3 for Figure 2 A schematic diagram of the matching surface of the transceiver components in the adapter board;

[0020] Figure 4 for Figure 2 A schematic diagram of the antenna element matching surface in the adapter board;

[0021] Figure 5 for Figure 3 or Figure 4 3D view of the RF connector;

[0022] Figure 6 This is a schematic diagram of the printed circuit board in an embodiment of the present invention;

[0023] Figure 7a This is a schematic diagram of the simulation results of standing waves and signal frequency in an embodiment of the present invention;

[0024] Figure 7b This is a schematic diagram illustrating the simulation results of insertion loss versus signal frequency in an embodiment of the present invention.

[0025] Figure 7c This is a schematic diagram illustrating the simulation results of isolation and signal frequency in an embodiment of the present invention.

[0026] [Attached image labels]

[0027] 1-Antenna unit, 2-Adapter board, 21-Guide pin, 22-Fixing plate, 23-Printed circuit board, 231-Signal via I, 2311-Inner layer pad I, 2312-Inner layer anti-pad I, 2313-Top layer pad I, 2314-Top layer anti-pad I, 232-Signal via II, 2321-Inner layer pad II, 2322-Inner layer anti-pad II, 2323-Top layer pad II, 2324-Top layer anti-pad II, 2325-Short post, 233-Ground hole, 234-Strip line, 24-RF connector I, 25-Fixing hole, 26-Antenna mounting hole, 27-RF connector II, 3-Transceiver assembly. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] This invention relates to an RF adapter printed circuit board, hereinafter referred to as adapter board 2. Embodiments of adapter board 2 include an RF connector, a printed circuit board 23, and a mounting housing, as shown below. Figures 1 to 6 As shown, the adapter board 2 enables high-density RF interconnection between antenna element 1 and transceiver assembly 3, significantly reducing the distance between the antenna array and transceiver assembly 3, eliminating the need for numerous RF cables, reducing weight, and simplifying assembly and maintenance. The adapter board 2 is installed at the rear end of antenna element 1, between antenna element 1 and transceiver assembly 3, facilitating the interconnection between them. This invention, through the printed circuit board and its matching RF connectors, enables the transmission of DC-18GHz RF signals on the stripline 234 of the printed circuit board, while also allowing blind mating of antenna element 1, transceiver assembly 3, and adapter board 2.

[0030] The printed circuit board 23 is used to realize radio frequency signal conversion. The radio frequency connectors are arranged on both sides of the printed circuit board 23 according to the orientation layout of the radio frequency connectors on the transceiver component 3 and the antenna unit 1. The surface of the printed circuit board 23 that matches the transceiver component 3 is equipped with radio frequency connector I 24, and the surface of the printed circuit board 23 that matches the antenna unit 1 is equipped with radio frequency connector II 27, so as to realize blind mating of radio frequency connector I 24 with the radio frequency connector on the transceiver component 3 and radio frequency connector II 27 with the radio frequency connector on the antenna unit 1, respectively.

[0031] To ensure the mechanical and environmental performance of the adapter board 2 and prevent the RF connector from desoldering and affecting its function and performance, a fixing housing is provided on both sides of the printed circuit board 23. The fixing housing includes two fixing plates 22, which are respectively fitted onto the two sides of the printed circuit board 23. Through holes are provided on the fixing plates 22 at positions corresponding to the RF connectors, allowing the connector's insertion end to be located within the through holes. Guide pins 21 are provided on the outer side of the fixing plate 22 that mates with the transceiver assembly 3 for guiding the installation of the transceiver assembly 3. Antenna mounting holes 26 are provided on the fixing plate 22 that mates with the antenna unit 1 for mounting the antenna unit 1. The guide pins 21 and antenna mounting holes 26 facilitate blind mating of the corresponding transceiver assembly 3 and antenna unit. Fixing holes 25 penetrate the fixing plates 22 and the printed circuit board 2 on the fixing housing for fixing the adapter board 2 to the corresponding device. Heat dissipation holes are arranged at intervals between the through holes on the fixing plates 22 for fixing the RF connectors. The fixing housing achieves the functions of fixing the RF connectors, strengthening the adapter board, guiding installation, and dissipating heat from the adapter board.

[0032] The connection methods between RF connectors and printed circuit boards include through-hole soldering, surface mount mounting, and surface mount soldering. Considering factors such as adapter board layout, transmission performance, assembly difficulty, and standardization, the RF connectors on antenna unit 1, printed circuit board 23, and transceiver assembly 3 use SSMP, SMA, or SMP series connectors, such as... Figure 1 The SSMP-J shown uses the existing RF(MF)-12JHT2 surface-mount contact from AVIC Optoelectronics. The RF connectors on antenna unit 1 and printed circuit board 23, as well as the RF connectors on transceiver assembly 3 and printed circuit board 23, require corresponding adapters for mating. For example... Figure 1 The SSMP-KK shown here has an adapter model of RF(MF)-12KK. Its interface size is similar to that of the SSMP, and the RF connector is soldered using a full surface mount soldering method.

[0033] Printed circuit board 23 is a multilayer hybrid printed circuit board used to transmit radio frequency (RF) signals, replacing cable assemblies for signal transmission. Compared to existing technologies, after the RF signal passes through the RF connector on adapter board 2, the signal transmission format changes from RF coaxial transmission to printed circuit board transmission, thus converting the transmission mode from RF coaxial structure transmission to stripline structure transmission. The performance design of the printed circuit board is mainly controlled in terms of impedance matching, insertion loss, and isolation.

[0034] Impedance matching is a key factor affecting signal transmission quality, primarily measured by the voltage standing wave ratio (VSWR). To meet the impedance matching requirements of double-sided RF adapter printed circuit boards (PCBs) with an 18GHz bandwidth, it is necessary to analyze various factors such as backplane stack-up relationships, stripline widths, process pads, and anti-pads. Through continuous optimization of parameters and structure, reliable and stable transmission of high-frequency signals between boards can be achieved. The PCB stack-up design based on impedance matching requirements is shown in Table 1.

[0035] The dielectric materials used in the microwave signal layer (between G2 and G4) in Table 1 are Tecumseh TSM-DS3 and FR28 microwave substrates. The core board uses TSM-DS3, and the prepreg uses FR-28. TSM-DS3 has a dielectric constant of 3, and FR-28 has a dielectric constant of 2.81; both have a loss of 0.0011. This material combination allows for a wider printed linewidth, which is beneficial for controlling the printed line impedance accuracy and reducing insertion loss. The dielectric materials can also be replaced with equivalent microwave materials from manufacturers such as Wuxi Ruilong RA300A and Rogers. Additionally, the prepreg materials between TOP and G2, and between G4 and BOT, use Panasonic M6 substrates, which can also be replaced with Rogers R4350B, Shengyi S6 series, etc. The printed circuit board includes at least two ground layers, namely ground layer I and ground layer II. When the thickness of the printed circuit board is greater than 2mm, one or two additional ground layers should be added between TOP and G2, and between BOT and G4. The intermediate material between the additional ground layers should be M6 board material, Rogers R4350B, Shengyi S6 series, etc.

[0036]

[0037] Table 1

[0038] The overall thickness of the printed circuit board is 2-3.7mm. Signal vias and ground vias 233 are distributed on it. Signal via I 231 is soldered to RF connector I 24, and signal via II 232 is soldered to RF connector II 27. The RF connectors on both sides of the printed circuit board correspond one-to-one and are interconnected through the signal vias. The parameters of the signal vias, ground vias 233, etc. are shown in Table 2.

[0039] From Table 2 and Figure 6It can be seen that signal via I 231 and signal via II 232 are connected by stripline 234, which is located on the RF layer S3. The through-layer of signal via I 231 is from TOP to S3, the through-layer of signal via II 232 is from BOT to S3, and the through-layer of ground via 233 is from TOP to BOT. The processing method of signal via I is blind via, filled with copper paste, and plated flat; the processing method of signal via II is back-drilled, filled with copper paste, and plated flat; the processing method of ground via is through-hole, filled with copper paste.

[0040] The drilling diameter of signal via I 231 ranges from 0.25mm to 0.35mm. The diameter of the inner pad I 2311 of signal via I 231 ranges from 0.45mm to 0.65mm, the diameter of the inner anti-pad I 2312 ranges from 1mm to 1.3mm, the short post is 0mm, the diameter of the surface pad I 2313 is 0.8mm, and the diameter of the surface anti-pad I 2314 ranges from 2mm to 2.4mm. The drilling diameter of signal via II 232 ranges from 0.25mm to 0.35mm. The diameter of the inner pad II 2321 of signal via II 2322 ranges from 0.45mm to 0.65mm, the diameter of the inner anti-pad II 2322 ranges from 1mm to 1.3mm, the short post 2325 is 0.15mm, the diameter of the surface pad II 2323 is 0.8mm, and the diameter of the surface anti-pad II 2324 ranges from 2mm to 2.4mm. The diameter range of 2324 is 2mm-2.4mm; the diameter range of the ground pad of ground hole 233 on the surface of the printed circuit board is 4.8mm-5.1mm.

[0041] Ground holes 233 are distributed on both sides of the stripline 234, and the distance between the centers of the corresponding ground holes on both sides of the stripline is 0.65-0.75mm; multiple ground holes are distributed around the signal vias, and the distance between the center of the signal vias and the center of the corresponding ground holes is 1.1-1.45mm.

[0042]

[0043]

[0044] Table 2

[0045] For isolation, the printed circuit board uses striplines, blind vias, back drilling, and copper paste filling to control isolation.

[0046] Based on the above parameters, a simulation was performed in HFSS. The simulation results are detailed below. Figures 7a to 7cSimulation results show that the VSWR is better than 1.35 in the DC to 18 GHz range, and decreases in the 18 GHz to 20 GHz range. The performance of the curved path is slightly worse, but there is still a large margin for the distance requirement (better than 2). The isolation is 84.6 dB, which is better than the required 50 dB. The insertion loss is about 0.29 dB. Considering the insertion loss of the two connectors is 0.51 dB, the total insertion loss is about 0.86 dB. The distance requirement is 1.5 dB, which still has a large margin.

[0047] The above embodiments are preferred embodiments. In other embodiments, the parameters in Tables 1 and 2 can be changed for simulation.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A radio frequency (RF) adapter printed circuit board, comprising a printed circuit board (23), characterized in that: The printed circuit board (23) is provided with radio frequency connectors on both sides. The radio frequency connectors on the two sides are radio frequency connector I (24) and radio frequency connector II (27), respectively. The radio frequency connectors on the two sides correspond one to one and communicate with each other. Radio frequency connector I (24) is used to plug into the antenna unit (1), and radio frequency connector II (27) on the other side is used to plug into the transceiver assembly (3). The printed circuit board (23) is arranged from top to bottom as solder mask layer I, top layer, ground layer I, radio frequency layer, ground layer II, bottom layer, and solder mask layer II. Ground holes (233) and signal vias corresponding to the radio frequency connectors are provided on the printed circuit board. The signal vias include signal via I (231) connected to radio frequency connector I (24) and signal via II (232) connected to radio frequency connector II (27). The through layer of signal via I (231) is solder mask layer I, top layer, ground layer I, and radio frequency layer. The through layer of signal via II (232) is solder mask layer II, bottom layer, and ground layer II. RF layer; the RF layer is provided with striplines (234) for connecting corresponding signal vias I (231) and II (232); the ground vias (233) are formed by passing through solder mask I, top layer, ground layer I, RF layer, ground layer II, bottom layer, and solder mask II; ground vias (233) are distributed on both sides of the striplines (234) and around the signal vias; the signal vias I (231) are provided with inner pads I (2311) and inner pads on the RF layer. Pad I (2312), surface pad I (2313) and surface anti-pad I (2314) are located on the top layer; the signal via II (232) is provided with inner pad II (2321) and inner anti-pad II (2322) located on the radio frequency layer, surface pad II (2323) and surface anti-pad II (2324) located on the bottom layer, and the signal via II (232) also includes a short post (2325); the ground via (233) is provided with a ground pad on the surface of the printed circuit board.

2. The radio frequency adapter printed circuit board according to claim 1, characterized in that: Fixing plates (22) are attached to both sides of the printed circuit board. The fixing plates (22) are provided with through holes corresponding to the positions of the radio frequency connectors. The tail end of the radio frequency connector is soldered to the printed circuit board (23), and the plug end is located in the through hole.

3. The radio frequency adapter printed circuit board according to claim 2, characterized in that: The fixed plate (22) has a guide pin (21) on the surface that mates with the transceiver assembly (3) for guiding the installation of the transceiver assembly (3), and an antenna mounting hole (26) on the surface that mates with the antenna unit (1) for installing the antenna unit (1).

4. The radio frequency adapter printed circuit board according to claim 1, characterized in that: The RF connector on the printed circuit board (23) is connected to the RF connector on the corresponding antenna unit (1) and the RF connector on the transceiver assembly (3) via an adapter.

5. The radio frequency adapter printed circuit board according to claim 1, characterized in that: A prepreg is placed between the top layer and ground layer I, a core board is placed between ground layer I and the radio frequency layer, a prepreg and a core board are placed sequentially between the radio frequency layer and ground layer II, and a prepreg is placed between ground layer II and the bottom layer.

6. The radio frequency adapter printed circuit board according to claim 5, characterized in that: The thickness of the printed circuit board is 2-3.7mm. One or two additional ground layers are added between the top layer and ground layer I, and between the bottom layer and ground layer II, and corresponding media are set between the added ground layers.

7. The radio frequency adapter printed circuit board according to claim 5, characterized in that: The signal via I (231) is processed as a blind hole, filled with copper paste, and plated flat; the signal via II (232) is processed as a back drill, filled with copper paste, and plated flat; the ground hole (233) is processed as a through hole and filled with copper paste.

8. The radio frequency adapter printed circuit board according to claim 1, characterized in that: The radio frequency connector I (24) and radio frequency connector II (27) are SSMP, SMA or SMP series connectors.

9. A radio frequency adapter printed circuit board according to claim 1 or 8, characterized in that: The drilling diameter of signal via I (231) ranges from 0.25mm to 0.35mm, the diameter of inner pad I (2311) of signal via I (231) ranges from 0.45mm to 0.65mm, the diameter of inner anti-pad I (2312) ranges from 1mm to 1.3mm, the short post is 0mm, the diameter of surface pad I (2313) is 0.8mm, and the diameter of surface anti-pad I (2314) ranges from 2mm to 2.4mm; the drilling diameter of signal via II (232) ranges from 0.25mm to 0.35mm, the diameter of inner pad II (2321) of signal via II (232) ranges from 0.45mm to 0.65mm, the diameter of inner anti-pad I (2312) ranges from 1mm to 1.3mm, the diameter of short post is 0mm, the diameter of surface pad I (2313) is 0.8mm, and the diameter of surface anti-pad I (2314) ranges from 2mm to 2.4mm; The inner anti-pad II (2322) has a diameter range of 1-1.3mm, the short post (2325) has a diameter of 0.15mm, the surface pad II (2323) has a diameter of 0.8mm, and the surface anti-pad II (2324) has a diameter range of 2mm-2.4mm; the ground pad (233) on the surface of the printed circuit board has a diameter range of 4.8mm-5.1mm; the ground holes (233) are distributed on both sides of the stripline (234), and the distance between the centers of the corresponding ground holes on both sides of the stripline is 0.65-0.75mm; multiple ground holes are distributed around the signal vias, and the distance between the center of the signal via and the center of the corresponding ground hole is 1.1-1.45mm.

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