A miniaturized multi-beam feed network

Abstract

This invention discloses a miniaturized multi-beam feed network, comprising a phase shifter, input ports P1-P4, output ports A1-A4, and four identical directional couplers. The phase shifter is connected to each of the four directional couplers. The first directional coupler is connected to ports A1 and A3, the second to ports P1 and P3, the third to ports A2 and A4, and the fourth to ports P2 and P4. Based on traditional microstrip lines and serpentine lines, this invention utilizes a double-layer bent microstrip transmission line structure to form the directional couplers and phase shifters, significantly reducing the size of the multi-beam feed network.

Description

Technical Field

[0001] This invention relates to power feed networks, and more particularly to a miniaturized multi-beam power feed network. Background Technology

[0002] The smooth operation of an RFID system largely depends on the connection established between the reader antenna and the tag antenna. For RFID readers, compared to the traditional time-division single-antenna operating mode (where only one antenna is activated and active at any given time), the simultaneous operation of a multi-beam antenna array offers higher gain and stronger anti-interference capabilities, effectively improving the reading efficiency and correct identification rate of the RFID system. Beamforming feed networks are one of the effective ways to generate multiple beams. By activating different network input ports each time, each antenna element receives different power and phase allocations, thus enabling the overall antenna array to generate beams in different directions.

[0003] However, the operating frequency range of UHF RFID is approximately 840MHz to 960MHz, which results in a relatively large physical size of the power supply network, making it difficult to meet the practical application requirements of portable RFID terminals. Therefore, research on miniaturization of multi-beam power supply networks operating in the 840MHz to 960MHz frequency range is of great importance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a miniaturized multi-beam feed network. Based on traditional microstrip lines and serpentine lines, a directional coupler and phase shifter are formed by a double-layer bent microstrip transmission line structure, which significantly reduces the size of the multi-beam feed network.

[0005] The objective of this invention is achieved through the following technical solution: a miniaturized multi-beam feed network, comprising a phase shifter, input ports P1~P4, output ports A1~A4, and four directional couplers with identical structures. The phase shifter is connected to the four directional couplers respectively. The first directional coupler is connected to ports A1 and A3 respectively, the second directional coupler is connected to ports P1 and P3 respectively, the third directional coupler is connected to ports A2 and A4 respectively, and the fourth directional coupler is connected to ports P2 and P4 respectively.

[0006] Furthermore, each of the aforementioned directional couplers includes a first metal ground plane, an upper dielectric substrate for the coupler, a lower dielectric substrate for the coupler, and four coupler ports; The lower surface of the upper dielectric substrate of the coupler is fixed to the upper surface of the first metal ground plane, and the upper surface of the lower dielectric substrate of the coupler is fixed to the lower surface of the first metal ground plane. Four bent metal strips are provided on the upper surface of the upper dielectric substrate of the coupler and the lower surface of the lower dielectric substrate of the coupler. The end of the first bent metal strip on the upper dielectric substrate of the coupler is connected to the first metal strip on the lower dielectric substrate of the coupler through a first conductive via penetrating the upper dielectric substrate, the first metal ground plane, and the lower dielectric substrate of the coupler, forming a whole as the first transmission line of the coupler; the starting end of the first bent metal strip on the upper dielectric substrate of the coupler is connected to the first coupler port, and the starting end of the first metal strip on the lower dielectric substrate of the coupler is connected to the second coupler port. The end of the second bent metal strip on the upper dielectric substrate of the coupler is connected to the second metal strip on the lower dielectric substrate of the coupler through a second conductive via penetrating the upper dielectric substrate, the first metal ground plane, and the lower dielectric substrate of the coupler, forming a whole as the second transmission line of the coupler; the starting end of the second bent metal strip on the upper dielectric substrate of the coupler is connected to the third coupler port, and the starting end of the second metal strip on the lower dielectric substrate of the coupler is connected to the second coupler port; The end of the third bent metal strip on the upper dielectric substrate of the coupler is connected to the third metal strip on the lower dielectric substrate of the coupler through a third conductive via penetrating the upper dielectric substrate, the first metal ground plane, and the lower dielectric substrate of the coupler, forming a whole as the third transmission line of the coupler; the starting end of the third bent metal strip on the upper dielectric substrate of the coupler is connected to the third coupler port, and the starting end of the third metal strip on the lower dielectric substrate of the coupler is connected to the fourth coupler port. The end of the fourth bent metal strip on the upper dielectric substrate of the coupler is connected to the fourth metal strip on the lower dielectric substrate of the coupler through a fourth conductive via penetrating the upper dielectric substrate, the first metal ground plane, and the lower dielectric substrate of the coupler, forming a whole as the fourth transmission line of the coupler; the starting end of the fourth bent metal strip on the upper dielectric substrate of the coupler is connected to the first coupler port, and the starting end of the fourth metal strip on the lower dielectric substrate of the coupler is connected to the fourth coupler port. In the directional coupler, the first coupler port is the input port, the second coupler port is the through port, the third coupler port is the coupling port, and the fourth coupler port is the isolation port.

[0007] Furthermore, the phase shifter includes a second metal ground plane, an upper dielectric substrate for the phase shifter, and a lower dielectric substrate for the phase shifter; The lower surface of the upper dielectric substrate of the phase shifter is fixed to the upper surface of the second metal ground plane, and the upper surface of the lower dielectric substrate of the phase shifter is fixed to the lower surface of the second metal ground plane. Four bent metal strips are provided on the upper surface of the upper dielectric substrate of the phase shifter and the lower surface of the lower dielectric substrate of the phase shifter. The starting end of the first bent metal strip on the upper dielectric substrate of the phase shifter and the starting end of the first bent metal strip on the lower dielectric substrate of the phase shifter are connected through a fifth conductive via penetrating the upper dielectric substrate, the second metal ground, and the lower dielectric substrate of the phase shifter, thus forming a whole as the first transmission line of the phase shifter. The end of the first bent metal strip on the lower dielectric substrate of the phase shifter serves as the first port of the phase shifter, and the end of the first bent metal strip on the upper dielectric substrate of the phase shifter serves as the second port of the phase shifter. The starting end of the second bent metal strip on the upper dielectric substrate of the phase shifter and the starting end of the second bent metal strip on the lower dielectric substrate of the phase shifter are connected through a sixth conductive via penetrating the upper dielectric substrate, the second metal ground plane, and the lower dielectric substrate of the phase shifter, thus forming a whole as the second transmission line of the phase shifter. The end of the second bent metal strip on the lower dielectric substrate of the phase shifter serves as the seventh port of the phase shifter, and the end of the second bent metal strip on the upper dielectric substrate of the phase shifter serves as the eighth port of the phase shifter. The starting end of the third bent metal strip on the upper dielectric substrate of the phase shifter and the starting end of the third bent metal strip on the lower dielectric substrate of the phase shifter are connected through the seventh conductive via penetrating the upper dielectric substrate, the second metal ground plane, and the lower dielectric substrate of the phase shifter, thus forming a whole as the third transmission line of the phase shifter. The end of the third bent metal strip on the lower dielectric substrate of the phase shifter serves as the fourth port of the phase shifter, and the end of the third bent metal strip on the upper dielectric substrate of the phase shifter serves as the third port of the phase shifter. The starting end of the fourth bent metal strip on the upper dielectric substrate of the phase shifter and the starting end of the fourth bent metal strip on the lower dielectric substrate of the phase shifter are connected through the eighth conductive via penetrating the upper dielectric substrate, the second metal ground plane, and the lower dielectric substrate of the phase shifter, thus forming a whole as the fourth transmission line of the phase shifter. The end of the fourth bent metal strip on the lower dielectric substrate of the phase shifter serves as the sixth port of the phase shifter, and the end of the fourth bent metal strip on the upper dielectric substrate of the phase shifter serves as the fifth port of the phase shifter.

[0008] Preferably, the length difference between the second transmission line and the first transmission line of the phase shifter is one-eighth of a wavelength. The length difference between the third transmission line and the fourth transmission line of the phase shifter is one-eighth of a wavelength. The second and third transmission lines of the phase shifter are of equal length, and the first and fourth transmission lines of the phase shifter are of equal length.

[0009] Preferably, the four transmission lines of the coupler are of equal length and each is a quarter wavelength.

[0010] Preferably, the first port of the phase shifter is connected to the second port of the third coupler, the second port of the phase shifter is connected to the third port of the fourth coupler, the third port of the phase shifter is connected to the third port of the third coupler, the fourth port of the phase shifter is connected to the second port of the second coupler, the fifth port of the phase shifter is connected to the third port of the second coupler, the sixth port of the phase shifter is connected to the second port of the first coupler, the seventh port of the phase shifter is connected to the second port of the fourth coupler, and the eighth port of the phase shifter is connected to the third port of the first coupler. The first port of the first coupler is connected to port A1, and the fourth port of the first coupler is connected to port A3; the first port of the second coupler is connected to port P1, and the fourth port of the second coupler is connected to port P3; the first port of the third coupler is connected to port A4, and the fourth port of the third coupler is connected to port A2; the fourth port of the fourth coupler is connected to port P2, and the first port of the fourth coupler is connected to port P4.

[0011] The beneficial effects of this invention are: based on traditional microstrip lines and serpentine lines, this invention forms directional couplers and phase shifters through a double-layer bent microstrip transmission line structure, which significantly reduces the volume of multi-beam feed networks. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating the network principle of the present invention; Figure 2 This is a schematic diagram of a directional coupler. Figure 3 This is a schematic diagram of the simulation test results of the miniaturized directional coupler in the embodiment; Figure 4 This is a schematic diagram of the phase shifter. Figure 5 A graph showing the phase shift amount of a miniaturized phase shifter as a function of frequency. Figure 6 The curves showing the S-parameters of the phase shifter as a function of frequency are shown. Detailed Implementation

[0013] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0014] like Figure 1As shown, a miniaturized multi-beam feed network includes a phase shifter, input ports P1~P4, output ports A1~A4, and four identical directional couplers. The phase shifter is connected to the four directional couplers respectively. The first directional coupler is connected to ports A1 and A3 respectively, the second directional coupler is connected to ports P1 and P3 respectively, the third directional coupler is connected to ports A2 and A4 respectively, and the fourth directional coupler is connected to ports P2 and P4 respectively.

[0015] In the embodiments of this application, each of the directional couplers includes a first metal ground plane, an upper dielectric substrate for the coupler, a lower dielectric substrate for the coupler, and four coupler ports; The lower surface of the upper dielectric substrate of the coupler is fixed to the upper surface of the first metal ground plane, and the upper surface of the lower dielectric substrate of the coupler is fixed to the lower surface of the first metal ground plane. like Figure 2 As shown, four bent metal strips are provided on the upper surface of the upper dielectric substrate of the coupler and the lower surface of the lower dielectric substrate of the coupler. The end of the first bent metal strip 1.1 on the upper dielectric substrate of the coupler is connected to the first metal strip 1.2 on the lower dielectric substrate of the coupler through a first conductive via 1.3 penetrating the upper dielectric substrate, the first metal ground plane, and the lower dielectric substrate, forming a whole as the first transmission line of the coupler. Figure 2 ①); The starting end of the first bent metal strip on the upper dielectric substrate of the coupler is connected to the first coupler port ( Figure 2 In K1), the starting end of the first metal strip on the lower dielectric substrate of the coupler is connected to the second coupler port. Figure 2 (K2 in the middle) The end of the second bent metal strip 2.1 on the upper dielectric substrate of the coupler is connected to the second metal strip 2.2 on the lower dielectric substrate of the coupler through a second conductive via 2.3 penetrating the upper dielectric substrate, the first metal ground plane, and the lower dielectric substrate, forming a whole as the second transmission line of the coupler. Figure 2 (②); The starting end of the second bent metal strip on the upper dielectric substrate of the coupler is connected to the third coupler port ( Figure 2 K3 in the coupler), the starting end of the second metal strip on the lower dielectric substrate of the coupler is connected to the second coupler port; The end of the third bent metal strip 3.1 on the upper dielectric substrate of the coupler is connected to the third metal strip 3.2 on the lower dielectric substrate of the coupler through a third conductive via 3.3 penetrating the upper dielectric substrate, the first metal ground plane, and the lower dielectric substrate of the coupler, forming a whole as the third transmission line of the coupler. Figure 2(③); The starting end of the third bent metal strip on the upper dielectric substrate of the coupler is connected to the third coupler port, and the starting end of the third metal strip on the lower dielectric substrate of the coupler is connected to the fourth coupler port. Figure 2 (K4 in the middle) The end of the fourth bent metal strip 4.1 on the upper dielectric substrate of the coupler is connected to the fourth metal strip 4.2 on the lower dielectric substrate of the coupler through a fourth conductive via 4.3 that passes through the upper dielectric substrate, the first metal ground plane, and the lower dielectric substrate of the coupler, forming a whole as the fourth transmission line of the coupler. Figure 2 (④ in the text) The starting end of the fourth bent metal strip on the upper dielectric substrate of the coupler is connected to the first coupler port, and the starting end of the fourth metal strip on the lower dielectric substrate of the coupler is connected to the fourth coupler port. In the directional coupler, the first coupler port is the input port, the second coupler port is the through port, the third coupler port is the coupling port, and the fourth coupler port is the isolation port.

[0016] The four transmission lines of the coupler are theoretically of equal length, each being a quarter wavelength.

[0017] like Figure 2 As shown, the plane containing the microstrip line on the upper dielectric substrate of the coupler is considered plane a, and the plane containing the microstrip line on the lower dielectric substrate of the coupler is considered plane b. The double-layer bent microstrip transmission line transmits signals in plane a and then reaches plane b through conductive vias to continue transmitting signals. To ensure smooth connection of the four double-layer bent microstrip transmission lines, the positions of each trace and port need to be carefully arranged. The input port K1 and coupling port K3 of the directional coupler are located in plane a, while the through port K2 and isolation port K4 are located in plane b. Therefore, the double-layer bent microstrip transmission lines ① and ④ between ports K1 and K2, and between ports K1 and K4, are first installed and routed from port K1 in plane a, and then reach plane b through conductive vias. Similarly, the double-layer bent microstrip transmission lines ② and ③ between ports K3 and K2, and between ports K3 and K4, are also first installed and routed from port K3 in plane a, and then reach plane b through conductive vias. Double-layer bent microstrip transmission lines ① and ② are connected at port K2, and ③ and ④ are connected at port K4. By gradually shortening the lateral length of the double-layer bent microstrip transmission lines, the resulting four triangular regions are placed inside the directional coupler, effectively utilizing the space inside the coupler and improving space utilization.

[0018] In the embodiments of this application, a novel directional branch coupler with a center frequency of 900MHz was designed and verified on an FR4 dielectric substrate with a layer thickness of 0.25mm (total thickness of 0.5mm), a relative permittivity of 4.4, and a loss tangent of 0.02. The metal traces and metal ground plane are made of copper with a thickness of 0.018mm. After optimization, the overall size of the miniaturized directional coupler is 12.92mm × 12.92mm, which is 91.94% smaller than the size of a conventional transmission line structure directional branch coupler (46.15mm × 44.85mm).

[0019] Simulation test results of miniaturized directional couplers are as follows: Figure 3 As shown, (a) are the S-parameters; (b) are the output phase difference between the through port and the coupled port. At the center frequency of 900MHz, the transmission coefficient S21 from the input port to the through port is -3.49dB, with the through port receiving 44.77% of the input power; the transmission coefficient S31 from the input port to the coupled port is -3.66dB, with the coupled port receiving 43.05% of the input power, and the power distribution ratio of the directional coupler is 1.04. In the full frequency range of 840MHz to 960MHz, the difference between S21 and S31 is no greater than 0.18dB, and the power distribution ratio is approximately 1; S11 is less than -15.8dB, and S41 is less than -17.4dB, indicating good port reflection and isolation; the phase difference between the output signals of the through port and the coupled port is -90.29° to -91.10°. These results demonstrate that miniaturized directional couplers can achieve miniaturization.

[0020] like Figure 4 As shown, the phase shifter includes a second metal ground plane, an upper dielectric substrate for the phase shifter, and a lower dielectric substrate for the phase shifter; The lower surface of the upper dielectric substrate of the phase shifter is fixed to the upper surface of the second metal ground plane, and the upper surface of the lower dielectric substrate of the phase shifter is fixed to the lower surface of the second metal ground plane. Four bent metal strips are provided on the upper surface of the upper dielectric substrate of the phase shifter and the lower surface of the lower dielectric substrate of the phase shifter. The starting end of the first bent metal strip 5.1 on the upper dielectric substrate of the phase shifter and the starting end of the first bent metal strip 5.2 on the lower dielectric substrate of the phase shifter are connected through a fifth conductive via 5.3 that passes through the upper dielectric substrate, the second metal ground plane, and the lower dielectric substrate of the phase shifter, thus forming a whole as the first transmission line of the phase shifter. Figure 4 (⑤) The end of the first bent metal strip 5.2 on the lower dielectric substrate of the phase shifter serves as the first port (Y1) of the phase shifter, and the end of the first bent metal strip 5.1 on the upper dielectric substrate of the phase shifter serves as the second port (Y2) of the phase shifter. The starting end of the second bent metal strip 6.1 on the upper dielectric substrate of the phase shifter and the starting end of the second bent metal strip 6.2 on the lower dielectric substrate of the phase shifter are connected through the sixth conductive via 6.3 penetrating the upper dielectric substrate, the second metal ground plane, and the lower dielectric substrate of the phase shifter, thereby forming a whole as the second transmission line of the phase shifter. Figure 4 (⑥) The end of the second bent metal strip 6.2 on the lower dielectric substrate of the phase shifter serves as the seventh port (Y7) of the phase shifter, and the end of the second bent metal strip 6.1 on the upper dielectric substrate of the phase shifter serves as the eighth port (Y8) of the phase shifter. The starting end of the third bent metal strip 7.1 on the upper dielectric substrate of the phase shifter and the starting end of the third bent metal strip 7.2 on the lower dielectric substrate of the phase shifter are connected through the seventh conductive via 7.3 penetrating the upper dielectric substrate, the second metal ground plane, and the lower dielectric substrate of the phase shifter, thus forming a whole as the third transmission line of the phase shifter. Figure 4 (⑦) The end of the third bent metal strip 7.2 on the lower dielectric substrate of the phase shifter serves as the fourth port (Y4) of the phase shifter, and the end of the third bent metal strip 7.1 on the upper dielectric substrate of the phase shifter serves as the third port (Y3) of the phase shifter. The starting end of the fourth bent metal strip 8.1 on the upper dielectric substrate of the phase shifter and the starting end of the fourth bent metal strip 8.2 on the lower dielectric substrate of the phase shifter are connected through the eighth conductive via 8.3 penetrating the upper dielectric substrate, the second metal ground plane, and the lower dielectric substrate of the phase shifter, thus forming a whole as the fourth transmission line of the phase shifter. Figure 4 (⑧) The end of the fourth bent metal strip 8.2 on the lower dielectric substrate of the phase shifter serves as the sixth port (Y6) of the phase shifter, and the end of the fourth bent metal strip 8.1 on the upper dielectric substrate of the phase shifter serves as the fifth port (Y5) of the phase shifter.

[0021] In the embodiments of this application, theoretically, the length difference between the second transmission line and the first transmission line of the phase shifter is one-eighth of a wavelength. The length difference between the third transmission line and the fourth transmission line of the phase shifter is also one-eighth of a wavelength. The second and third transmission lines of the phase shifter are of equal length, and the first and fourth transmission lines of the phase shifter are of equal length.

[0022] In the phase shifter, transmission lines ⑤ and ⑧ are used for direct connection to the directional coupler, serving as reference lines for the phase shifter; transmission lines ⑥ and ⑦ act as a -45° phase shifter. The directional coupler is connected to the left side of this miniaturized phase shifter. The through port K2 of the directional coupler is connected to port Y1 of transmission line ⑤ on the phase shifter, thus both are located in plane b; the coupling port K3 of the directional coupler is connected to port Y3 of transmission line ⑦ on the phase shifter, thus both are located in plane a. Therefore, transmission lines ⑤ and ⑧ are routed from ports Y1 and Y6 located in plane b, respectively, through conductive vias to plane a, and then through metal traces to ports Y2 and Y5, before continuing to connect to the directional coupler; transmission lines ⑥ and ⑦ are routed from ports Y8 and Y3 located in plane a, respectively, through conductive vias to plane b, and then through metal traces to ports Y7 and Y4, before continuing to connect to the directional coupler.

[0023] A transmission line with a length of one-quarter wavelength will introduce a 90° phase shift. Theoretically, the phase shift from port Y1 to port Y2 should precede the phase shift from port Y3 to port Y4 by 45°, and similarly, the phase shift from port Y5 to port Y6 should precede the phase shift from port Y7 to port Y8 by 45°. Therefore, the total length of transmission lines ⑥ and ⑦ should be one-eighth of a wavelength longer than the total length of transmission lines ⑤ and ⑧. Of course, this is only a theoretical calculation. Due to various factors, the actual excess length of transmission lines ⑥ and ⑦ compared to transmission lines ⑤ and ⑧ will be determined by HFSS optimization.

[0024] A model was established using an FR4 dielectric substrate with a layer thickness of 0.25 mm, a relative permittivity of 4.4, and a loss tangent of 0.02, and a copper material with a thickness of 0.018 mm. After optimization and adjustment, the phase shift amount of the miniaturized phase shifter was obtained as follows: Figure 5 The variation of S-parameters with frequency Figure 6 , where (a) reflection coefficient; (b) insertion loss.

[0025] As can be seen, within the entire operating frequency band of 840MHz to 960MHz, the reflection coefficient of all ports is less than -24.06dB, and the insertion loss of the phase shifter is less than 0.27dB. At the center frequency of 900MHz, the phase shift of the phase shifter relative to the reference transmission line is -45.44°, and the phase shift throughout the entire operating frequency band is -45°±3°. The miniaturized phase shifter based on the double-layer bent microstrip transmission line design exhibits low phase shift error, good port matching characteristics, low insertion loss, and good output amplitude balance.

[0026] In the embodiments of this application, in order to avoid wiring intersections and further reduce the size of the power supply network, we refer to the schematic diagram of the 4×4 Butler matrix and use 4 miniaturized directional couplers and 1 miniaturized phase shifter to construct the network.

[0027] When using a PCB design, the first metal ground plane of the coupler and the second metal ground plane of the phase shifter can be placed on the same metal ground plane. The upper dielectric substrate of the coupler and the upper dielectric substrate of the phase shifter can also use the same dielectric substrate, as can the lower dielectric substrate of the coupler and the lower dielectric substrate of the phase shifter. In other words, by using an upper dielectric substrate, a metal ground plane, and a lower dielectric substrate, microstrip lines can be etched onto the upper and lower dielectric substrates to integrate the phase shifter and four directional couplers, placing the phase shifter in the center. This further reduces the size of the power supply network. To more closely reflect actual manufacturing conditions, the original simulation model structure was modified using a PCB design. 1. The original structure of the double-layer bent microstrip transmission line was metal trace – dielectric substrate – metal ground plane – dielectric substrate – metal trace. Now, an additional metal ground plane and a dielectric substrate used as adhesive are added between the two dielectric substrates, changing the structure to metal trace – dielectric substrate – metal ground plane – adhesive – metal ground plane – dielectric substrate – metal trace. This only requires etching the circuit diagrams onto two complete PCB boards during manufacturing, and then bonding them to the adhesive in the middle with the metal ground plane facing inwards. The adhesive board material remains FR4 with a relative permittivity of 4.4 and a thickness of 0.1mm.

[0028] 2. To ensure successful soldering of the adapter, the microstrip line is extended at each input / output port to widen the port distance and provide sufficient space for soldering.

[0029] 3. Due to the narrow width of the metal traces of the microstrip transmission lines in the power supply network, metal pads are designed at each port and on both sides of the port to ensure sufficient area for soldering of the connector probes and ground pins.

[0030] 4. At each port, a metal ground plane is led to the outer layer through metal vias and connected to additionally designed pads to ensure ground continuity.

[0031] 5. Considering the actual processing accuracy, the thickness of all metal layers was changed from the original 0.018mm to 0.035mm (i.e. 1 ounce), and hole rings were designed at both ends of all metallized conductive vias to ensure the conduction of transmission signals.

[0032] The entire power supply network consists of four directional couplers connected to a central phase shifter. The two outer ports of each directional coupler serve as the input and output ports of the power supply network and are connected to SMA connectors.

[0033] The above description represents preferred embodiments of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technical or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A miniaturized multi-beam feed network, characterized in that: It includes a phase shifter, input ports P1~P4, output ports A1~A4, and four directional couplers with the same structure. The phase shifter is connected to the four directional couplers respectively. The first directional coupler is connected to ports A1 and A3 respectively, the second directional coupler is connected to ports P1 and P3 respectively, the third directional coupler is connected to ports A2 and A4 respectively, and the fourth directional coupler is connected to ports P2 and P4 respectively. Each of the aforementioned directional couplers includes a first metal ground plane, an upper dielectric substrate, a lower dielectric substrate, and four coupler ports; The lower surface of the upper dielectric substrate of the coupler is fixed to the upper surface of the first metal ground plane, and the upper surface of the lower dielectric substrate of the coupler is fixed to the lower surface of the first metal ground plane. Four bent metal strips are provided on the upper surface of the upper dielectric substrate of the coupler and the lower surface of the lower dielectric substrate of the coupler. The end of the first bent metal strip (1.1) on the upper dielectric substrate of the coupler is connected to the first metal strip (1.2) on the lower dielectric substrate of the coupler through a first conductive via (1.3) that passes through the upper dielectric substrate, the first metal ground plane, and the lower dielectric substrate of the coupler, forming a whole as the first transmission line of the coupler; the starting end of the first bent metal strip on the upper dielectric substrate of the coupler is connected to the first coupler port, and the starting end of the first metal strip on the lower dielectric substrate of the coupler is connected to the second coupler port; The end of the second bent metal strip (2.1) on the upper dielectric substrate of the coupler is connected to the second metal strip (2.2) on the lower dielectric substrate of the coupler through a second conductive via (2.3) that passes through the upper dielectric substrate, the first metal ground plane, and the lower dielectric substrate of the coupler, forming a whole as the second transmission line of the coupler; the starting end of the second bent metal strip on the upper dielectric substrate of the coupler is connected to the third coupler port, and the starting end of the second metal strip on the lower dielectric substrate of the coupler is connected to the second coupler port; The end of the third bent metal strip (3.1) of the upper dielectric substrate of the coupler is connected to the third metal strip (3.2) of the lower dielectric substrate of the coupler through the third conductive via (3.3) that passes through the upper dielectric substrate, the first metal ground plane and the lower dielectric substrate of the coupler, forming a whole as the third transmission line of the coupler; the starting end of the third bent metal strip of the upper dielectric substrate of the coupler is connected to the third coupler port, and the starting end of the third metal strip of the lower dielectric substrate of the coupler is connected to the fourth coupler port; The end of the fourth bent metal strip (4.1) of the upper dielectric substrate of the coupler is connected to the fourth metal strip (4.2) of the lower dielectric substrate of the coupler through the fourth conductive via (4.3) that passes through the upper dielectric substrate, the first metal ground plane, and the lower dielectric substrate of the coupler, forming a whole as the fourth transmission line of the coupler; the starting end of the fourth bent metal strip of the upper dielectric substrate of the coupler is connected to the first coupler port, and the starting end of the fourth metal strip of the lower dielectric substrate of the coupler is connected to the fourth coupler port; The phase shifter includes a second metal ground plane, an upper dielectric substrate for the phase shifter, and a lower dielectric substrate for the phase shifter. The lower surface of the upper dielectric substrate of the phase shifter is fixed to the upper surface of the second metal ground plane, and the upper surface of the lower dielectric substrate of the phase shifter is fixed to the lower surface of the second metal ground plane. Four bent metal strips are provided on the upper surface of the upper dielectric substrate of the phase shifter and the lower surface of the lower dielectric substrate of the phase shifter. The starting end of the first bent metal strip (5.1) on the upper dielectric substrate of the phase shifter and the starting end of the first bent metal strip (5.2) on the lower dielectric substrate of the phase shifter are connected by a fifth conductive via (5.3) that passes through the upper dielectric substrate, the second metal ground plane, and the lower dielectric substrate of the phase shifter, thus forming a whole as the first transmission line of the phase shifter. The end of the first bent metal strip (5.2) on the lower dielectric substrate of the phase shifter serves as the first port of the phase shifter, and the end of the first bent metal strip (5.1) on the upper dielectric substrate of the phase shifter serves as the second port of the phase shifter. The starting end of the second bent metal strip (6.1) on the upper dielectric substrate of the phase shifter and the starting end of the second bent metal strip (6.2) on the lower dielectric substrate of the phase shifter are connected through the sixth conductive via (6.3) that passes through the upper dielectric substrate of the phase shifter, the second metal ground plane and the lower dielectric substrate of the phase shifter, thus forming a whole as the second transmission line of the phase shifter. The end of the second bent metal strip (6.2) on the lower dielectric substrate of the phase shifter serves as the seventh port of the phase shifter, and the end of the second bent metal strip (6.1) on the upper dielectric substrate of the phase shifter serves as the eighth port of the phase shifter. The starting end of the third bent metal strip (7.1) on the upper dielectric substrate of the phase shifter and the starting end of the third bent metal strip (7.2) on the lower dielectric substrate of the phase shifter are connected through the seventh conductive via (7.3) that passes through the upper dielectric substrate, the second metal ground plane and the lower dielectric substrate of the phase shifter, thus forming a whole as the third transmission line of the phase shifter. The end of the third bent metal strip (7.2) on the lower dielectric substrate of the phase shifter serves as the fourth port of the phase shifter, and the end of the third bent metal strip (7.1) on the upper dielectric substrate of the phase shifter serves as the third port of the phase shifter. The starting end of the fourth bent metal strip (8.1) on the upper dielectric substrate of the phase shifter and the starting end of the fourth bent metal strip (8.2) on the lower dielectric substrate of the phase shifter are connected through the eighth conductive via (8.3) that passes through the upper dielectric substrate, the second metal ground plane and the lower dielectric substrate of the phase shifter, thus forming a whole as the fourth transmission line of the phase shifter. The end of the fourth bent metal strip (8.2) on the lower dielectric substrate of the phase shifter serves as the sixth port of the phase shifter, and the end of the fourth bent metal strip (8.1) on the upper dielectric substrate of the phase shifter serves as the fifth port of the phase shifter.

2. The miniaturized multi-beam feed network according to claim 1, characterized in that: The length difference between the second transmission line and the first transmission line of the phase shifter is one-eighth of a wavelength.

3. The miniaturized multi-beam feed network according to claim 1, characterized in that: The length difference between the third and fourth transmission lines of the phase shifter is one-eighth of a wavelength.

4. A miniaturized multi-beam feed network according to claim 1, characterized in that: The second transmission line of the phase shifter is the same length as the third transmission line of the phase shifter, and the first transmission line of the phase shifter is the same length as the fourth transmission line.

5. A miniaturized multi-beam feed network according to claim 1, characterized in that: The four transmission lines of the coupler are of equal length and each is a quarter wavelength.

6. A miniaturized multi-beam feed network according to claim 1, characterized in that: The first port of the phase shifter is connected to the second port of the third coupler; the second port of the phase shifter is connected to the third port of the fourth coupler; the third port of the phase shifter is connected to the third port of the third coupler; the fourth port of the phase shifter is connected to the second port of the second coupler; the fifth port of the phase shifter is connected to the third port of the second coupler; the sixth port of the phase shifter is connected to the second port of the first coupler; the seventh port of the phase shifter is connected to the second port of the fourth coupler; and the eighth port of the phase shifter is connected to the third port of the first coupler. The first port of the first coupler is connected to port A1, and the fourth port of the first coupler is connected to port A3; the first port of the second coupler is connected to port P1, and the fourth port of the second coupler is connected to port P3; the first port of the third coupler is connected to port A4, and the fourth port of the third coupler is connected to port A2; the fourth port of the fourth coupler is connected to port P2, and the first port of the fourth coupler is connected to port P4.

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