CN114744417A - Feed network system - Google Patents

Abstract

The invention discloses a feed network system, and belongs to the technical field of antenna feed. The power combining network comprises four constant-amplitude 90-degree network sub-arrays of 2x2 rectangular arrays and a power combining network which is positioned at the bottom of the sub-arrays and consists of a four-in-one Wilkinson power combiner; the constant-amplitude 90-degree network sub-arrays of the four arrays realize signal synthesis output through a four-in-one Wilkinson power synthesizer in cascade connection; the constant-amplitude 90-degree network subarray comprises a first metal grounding plate, a first microwave substrate, a first metal signal line, a first semi-solidified sheet, a second microwave substrate, a second metal grounding plate, a second semi-solidified sheet, a second metal signal line, a third microwave substrate and a third metal grounding plate which are sequentially stacked from top to bottom; microwave substrates are bonded through prepregs; the feed network capable of butting the right-handed, equal-amplitude and 90-degree antenna signals of the four feed points is realized. The invention reduces the horizontal and transverse size of the feed network and realizes the miniaturization and high integration of the antenna array.

Description

Feed network system

Technical Field

The invention relates to the technical field of antenna feed, in particular to a feed network system suitable for a high-density vertical interconnection technology PCB.

Background

At present, a feed network mostly adopts a form of a power synthesizer and a phase shifting line, the dispersion effect of the phase shifting line is obvious, the influence of the phase shifting line on the phase is only aimed at a certain frequency point or a very narrow bandwidth, the structure is not symmetrical and uniform enough, and the reconfigurability is poor.

The current LTCC and HTCC technologies are complex in processing technology, one layer of LTCC and HTCC technologies are manufactured, and a plurality of design reliability difficulties exist, and the shrinkage and the thermal expansion coefficient of the substrate and the wiring during cofiring are one of important challenges, which are mainly reflected in three aspects: the sintering densification finishing temperatures are different; the sintering shrinkage rates of the substrate and the slurry are inconsistent; the sintering densification speed is not matched, the mismatching is easy to cause the surface of the substrate after sintering to be uneven, warped and layered, and the adhesion of metal wiring is reduced as another result of the mismatching. LTCC substrates are fragile, have low thermal conductivity, are still a critical issue for heat dissipation, and have long processing cycles, are expensive, and are not convenient for large-scale production in short cycles.

Among the stripline antenna feed network of present multilayer microwave printed board processing preparation, processing simple manufacture, material microstructure is even, can realize low dielectric constant and lower loss, and thermal behavior and mechanical properties are all guaranteed, but two-sided blind hole technical application is less, leads to electromagnetic shield effect poor, influences the transmission of signal between the multiply wood, and is mostly one deck planar structure, and the size is great, is unfavorable for miniaturized development.

The southeast university of 2021 discloses a phased-array antenna feed network, which is realized by adopting a high-density multilayer hybrid board, but only has a single-side blind hole processing technology, and does not realize double-sided blind holes and buried hole processes.

In the PCB processing technology, the distance between a grounding hole and a buried resistance edge is at least 500um safety distance, so that the situation that punching is deviated to the buried resistance can be guaranteed, and the design of the multilayer microwave printed board is limited by the processing precision.

Disclosure of Invention

In view of the above problems in the background art, the present invention provides a feeding network system. The system adopts a longitudinal three-dimensional stacking form, reduces the horizontal and transverse sizes of the feed network, and realizes the miniaturization and high integration of the antenna array.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a feed network system comprises four equal-amplitude 90-degree network sub-arrays arranged in a rectangular array and a power synthesis network positioned at the bottom of the network sub-arrays; the constant-amplitude 90-degree network sub-arrays of the four arrays realize signal synthesis output by cascading a four-in-one Wilkinson power synthesizer; the constant-amplitude 90-degree network subarray comprises a first metal grounding plate, a first microwave substrate, a first metal signal line, a first prepreg, a second microwave substrate, a second metal grounding plate, a second prepreg, a second metal signal line, a third microwave substrate and a third metal grounding plate which are sequentially stacked from top to bottom; microwave substrates are bonded through prepregs;

the first electric bridge and the second electric bridge in the constant-amplitude 90-degree network are both 90-degree electric bridges, and the ports of the first electric bridge and the second electric bridge are both positioned on one side of the corresponding edge of the constant-amplitude 90-degree network; wherein the third bridge is a 180 ° bridge; a first difference port and a second difference port of the first bridge and a third difference port and a fourth difference port of the second bridge are respectively connected with four feeding endpoints corresponding to the antenna; the first combined port of the first bridge is connected with the fifth difference port of the third bridge, and the second combined port of the second bridge is connected with the sixth difference port of the third bridge; the third combined port of the third bridge is used for outputting an antenna signal;

the first metal grounding plate is connected with the second metal grounding plate through the first metalized shielding hole; the first metal grounding plate is connected with the third metal grounding plate through the second metalized shielding hole, and the second metalized shielding hole penetrates through the second metal grounding plate.

Further, the constant-amplitude 90-degree network is of a symmetrical structure.

Further, the antenna is a microstrip antenna; the feed network system is connected with four feed endpoints of the microstrip antenna through the SSMP connector; the constant-amplitude 90-degree network subarray is connected with the Wilkinson power synthesizer through an SSMP connector.

Further, the first combined port of the first bridge and the fifth differential port of the third bridge are connected through corresponding second metallized radio frequency holes; and the second combined port of the second electric bridge and the sixth difference port of the third electric bridge are connected through corresponding second metalized radio frequency holes.

Furthermore, the first differential port and the second differential port of the first bridge and the third differential port and the fourth differential port of the second bridge are respectively connected with four corresponding feed terminals of the antenna through corresponding third metallized radio frequency holes above the respective ports; and the third combined port of the third bridge outputs an antenna signal through a fourth metallized radio frequency hole positioned below the third combined port.

Further, the axes of the third metallized rf hole and the fourth metallized rf hole of the first differential port of the first bridge and the third combined port of the third bridge are offset and share the second metallized shielding hole; and the axes of the upper-layer metallized radio frequency hole and the lower-layer metallized radio frequency hole are superposed and share the corresponding second metallized shielding hole.

Further, the isolation ports of the first bridge, the second bridge and the third bridge are all equivalently grounded by adopting sector metal; the radius of the fan-shaped metal is a quarter wavelength.

Further, a third metallized radio frequency hole is punched before one-time mixed pressing, and the width of a welding disk ring is 3 mils;

the fourth metallized radio frequency hole is punched before secondary mixed pressing, and the width of a welding disc ring is 3 mils;

and the second metallized radio frequency hole is drilled by back drilling after secondary mixed pressing, and the width of the bonding pad ring is 5 mils.

The invention adopts the technical scheme to produce the beneficial effects that:

1. the feed network of the invention adopts a strip line structure, and because the upper layer and the lower layer which are adjacent to each other are provided with metal floors, the energy leakage is less and the interference of an external circuit can be basically avoided. And moreover, the strip line structure is adopted to be presented in a longitudinal three-dimensional stacking form, so that the horizontal and transverse sizes of the feed network can be reduced, and the miniaturization and high integration of the antenna array are realized.

2. The invention adopts a multilayer microwave printed board mode, the isolation resistor adopts a buried resistance mode to simplify the circuit design, the distance between the grounding hole and the buried resistance edge in the PCB processing technology is at least 500um safety distance, the punching can not be ensured to be deviated to the buried resistance, in order to avoid the limitation of the processing precision of the microwave printed board, 1/4 lambda sector metal is equivalently substituted for the grounding hole at the bridge isolation port, thereby realizing equivalent grounding and simultaneously improving the isolation degree of the bridge. The diameters of the signal via holes and the shielding holes and the corresponding sizes of the pad rings are reasonably arranged according to the proportion, so that the processing and manufacturing of double-sided blind holes and middle layer buried holes in the multilayer microwave printed board are realized. The signal transmission shares the second metallized shielding hole, so that a good electromagnetic shielding effect is achieved. Compared with the LTCC process and the HTCC process, the low-dielectric-constant high-loss low-loss high-temperature co-fired ceramic material is simple to manufacture, uniform in microstructure, capable of achieving low dielectric constant and low loss, guaranteed in thermal performance and mechanical performance, low in processing cost, short in processing period, convenient to produce in batches, and wide in application value and applicability.

3. Most of the existing feed networks adopt a mode of connecting a phase shifting line and a power synthesizer, the dispersion effect of the phase shifting line is obvious, and the influence of the phase shifting line on the phase is only aimed at a certain frequency point or an extremely narrow bandwidth. The phase control can be realized only by adopting the 90-degree electric bridge, the 180-degree electric bridge and the Wilkinson power synthesizer, the structure is symmetrical, the use of a phase shifting line can be avoided, the isolation degree in a corresponding frequency band is high, the phase unbalance degree is low, the design structure is symmetrical and uniform, and the reconfigurability is strong.

4. The feed network can be butted with antenna units with four feed points, and compared with single-point and double-point feed networks, the 3dB axial ratio bandwidth of the antenna can be remarkably improved on the basis of keeping the high gain of the microstrip antenna.

Drawings

FIG. 1 is a schematic diagram of an antenna feed network system according to the present invention;

FIG. 2 is a schematic diagram of a constant-amplitude, 90-degree network hierarchy in an embodiment of the present invention;

FIG. 3 is a detailed block diagram of a constant-amplitude, 90-degree network in an embodiment of the present invention;

fig. 4 is a design diagram of a feed network after 1/4 λ sector equivalent grounding in the embodiment of the present invention;

FIG. 5 is a schematic diagram of a laminated structure of a constant-amplitude 90-degree network PCB in an embodiment of the invention;

FIG. 6 is a schematic diagram of a front view of a 90-degree network via hole and a semi-conductive via hole with equal amplitude according to an embodiment of the present invention;

FIG. 7 is a schematic top view of a port-shared ground via in an embodiment of the present invention;

FIG. 8 is a schematic diagram of a back-drilling process stub according to an embodiment of the present invention;

fig. 9 is a return loss diagram of a constant-amplitude 90 ° network port according to the present embodiment;

fig. 10 is a constant-amplitude 90 ° network port insertion loss diagram according to the present embodiment;

fig. 11 is a diagram of isolation between ports of the equal-amplitude 90 ° network according to the present embodiment;

FIG. 12 is a phase diagram of a 90 ° network port with equal amplitude according to the present embodiment;

fig. 13 is a return loss diagram of the port of the wilkinson power combiner according to the embodiment;

fig. 14 is a diagram of the insertion loss of the port of the wilkinson power combiner in the present embodiment.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and specific embodiments.

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

The embodiment of the invention relates to an antenna feed network system based on a multilayer mixed-voltage buried resistance technology and a high-density vertical interconnection technology PCB technology, which comprises the following steps: the power transmission network comprises a first bridge, a second bridge and a third bridge which are connected with each other to form an upper layer and a lower layer of transmission network which have the same amplitude and phase difference of 90 degrees in sequence and a four-in-one Wilkinson power synthesis network. The feed network unit comprises four feed points which are in butt joint with the upper layer antenna.

The whole feed network adopts multilayer stripline structure to appear in vertical three-dimensional stacking form, and the upper and lower two adjacent layers of wiring all have metal floors, can reduce the horizontal and transverse size of feed network, realize the miniaturization and the high integration of antenna array.

Wherein the first bridge, the second bridge are 90 ° bridges, the third bridge is 180 ° bridge, and both the 90 ° bridge and the 180 ° bridge have four ports.

The first electric bridge and the second electric bridge in the constant-amplitude 90-degree network are both 90-degree electric bridges, and the ports of the first electric bridge and the second electric bridge are both positioned on one side of the corresponding edge of the constant-amplitude 90-degree network; wherein the third bridge is a 180 ° bridge; the first difference port and the second difference port of the first bridge and the third difference port and the fourth difference port of the second bridge are respectively connected with four feeding end points corresponding to the antenna; the first combined port of the first bridge is connected with the fifth difference port of the third bridge, and the second combined port of the second bridge is connected with the sixth difference port of the third bridge; the third combined port of the third bridge is used for outputting an antenna signal;

in this embodiment, the 2-port and the 3-port of the first bridge are difference ports, which are respectively a first difference port and a second difference port of the first bridge; the port 6 is a combined port, which is a first combined port of the first bridge, the port 10 is an isolated port, and the port 4 and the port 5 of the second bridge are differential ports, which are respectively a third differential port and a fourth differential port of the second bridge; the 7 port is a closed port which is a second closed port of the second bridge; the 11 ports are isolated ports. The 8 port and the 9 port of the third bridge are differential ports, namely a fifth differential port and a sixth differential port of the third bridge; the port 1 is a combined port and is a third combined port of the third bridge; the 12 ports are isolated ports. The 2 port and the 3 port of the first electric bridge and the 4 port and the 5 port of the second electric bridge are connected with four feeding end points corresponding to the antenna, and the feeding relations of equal amplitude and 90 degrees are respectively formed.

The 6 ports of the first bridge are connected with the 8 ports of the third bridge, the 7 ports of the second bridge are connected with the 9 ports of the third bridge, and finally received antenna signals are output from the 1 port of the third bridge.

The isolation resistors of the Wilkinson power combiner are all in the form of 100 omega buried resistors. The four constant-amplitude 90-degree feed receiving subarrays realize the synthesis and output of radio frequency receiving signals through a cascade four-in-one Wilkinson power synthesizer.

The system is applied to a receiving phased array antenna system; the working frequency of the system is 19.6-21.2 GHz.

According to the invention, the isolation ports of the 90-degree electric bridge and the 180-degree electric bridge are required to be connected with a 50-ohm matching resistor for grounding treatment, the resistor adopts a buried resistance process, and because the grounding hole is close to the buried resistance distance and the limitation of the processing process precision cannot be realized, 1/4 lambda sector metal is adopted to equivalently replace the grounding hole, so that equivalent grounding is realized, the limitation of the processing process is broken through, and the high isolation degree of the electric bridge is realized.

The invention is limited by the multilayer board via hole processing technology, peripheral grounding holes are required to be shared between ports 1 and 2 and interconnection ports (ports 6 and 8, and ports 7 and 9), and when a circuit pattern is arranged on a lower layer at a position corresponding to a through hole, an upper layer of metalized hole is reserved according to the requirement of a laminated structure, and the through hole is changed into a semi-conductive blind hole. Simulation results show that the method can not only ensure the original performance, but also improve the isolation and reduce the return loss, and meet the actual processing requirements.

The invention breaks through the inherent technical bottleneck, blind holes and buried holes adopt various punching modes and different sizes of pad rings, the buried holes in the multilayer microwave printed board adopt a technological method of punching an upper layer and a lower layer by back drilling after mixed pressing, when the holes are punched in the back drilling mode, the depth of a back drilling residual end is 0.15mm, the width of the pad ring is reasonably set by combining the actual technological processing level after HFSS simulation, and the miniaturized double-sided buried holes of radio frequency signals are enabled to be realized in 5 layers of microwave mixed pressing boards, so that a feed network is presented in a multilayer three-dimensional framework mode, the size of a constant-amplitude 90-degree network unit is 12mm multiplied by 12mm, and the aims of integration and miniaturization of the phased array antenna feed network are achieved.

The feed network and the upper microstrip antenna system can be interconnected by using a connector, and can also be directly integrated with mixed voltage. Due to the maturity of the multilayer mixed-voltage buried resistance technology and the high-density vertical interconnection technology PCB technology, the mass production of large-scale antenna arrays with high integration level becomes possible. Miniaturization and high integration of the feed network can be realized.

In the embodiment, an array structure of four antenna units is adopted, and a feed network of the present invention is adopted, referring to fig. 1 and fig. 2, the whole constant-amplitude 90-degree network is formed by mixing and pressing 5 layers of microwave boards, and the lamination sequence is as follows: the microwave integrated circuit comprises a metal, a microwave substrate, a metal, a prepreg, a metal, a microwave substrate and a metal, wherein the microwave substrates are bonded through the prepreg, a first bridge circuit and a second bridge circuit are positioned on a metal L2 layer, and a third bridge circuit is positioned on a metal L4 layer; the metal L1 layer, the metal L3 layer, and the metal L5 layer are all metal ground plates, and are respectively a first metal ground plate, a second ground plate, and a third metal ground plate. The whole feed network structure is divided into three layers: the first layer is formed by a first electric bridge and a second electric bridge, the first layer and the third electric bridge of the second layer are mutually connected to form an upper layer right-handed constant-amplitude 90-degree network and are cascaded with a superior microstrip antenna through four ports of 2, 3, 4 and 5. The third layer is a four-in-one Wilkinson power combiner.

Wherein the first bridge, the second bridge are 90 ° bridges, the third bridge is 180 ° bridge, and both the 90 ° bridge and the 180 ° bridge have four ports.

The 2 port and the 3 port of the first electric bridge are differential ports, the 6 port is a closed port, the 10 port is an isolated port, the 4 port and the 5 port of the second electric bridge are differential ports, the 7 port is a closed port, and the 11 port is an isolated port. The 8 port and the 9 port of the third bridge are differential ports, the 1 port is a closed port, and the 12 port is an isolated port. All the isolated ports are grounded through the via holes after being connected with the 50 omega buried resistor.

The 2-port and the 3-port of the first bridge and the 5-port of the 4-port of the second bridge are connected with four feed points of the antenna unit at the upper stage, and the four feed points form a constant-amplitude 90-degree feed relation respectively.

The 6 ports of the first electric bridge are connected with the 8 ports of the third point bridge, the 7 ports of the second electric bridge are connected with the 9 ports of the third point bridge, and finally received right-hand equal-amplitude 90-degree antenna signals are output from the 1 port of the third electric bridge.

The scattering matrix S describing the 90 ° bridge is as follows:

all ports are matched, and the power input from the combined port is equally distributed to two differential ports, with a 90 ° phase shift between the two output ports, and no power is coupled to the isolated port. A 90 hybrid network has a high degree of symmetry, with any port being an input port, the output port always being on the opposite side of the input port of the network, and the isolated port being the remaining port on the same side of the input port. The symmetry response in the scattering matrix is that each row can be transposed from the first row.

The scattering matrix S describing the 180 ° bridge is as follows:

in a 180 hybrid network, referring to fig. 3, when used as a combiner, the input signals are applied at ports 8 and 9, the sum of the input signals will be formed at port 1, and the difference of the input signals will be formed at ports 1 and 2.

The four-way Wilkinson power combiner is provided with four input ports and one output combining port. A wilkinson power combiner is one such network: when the output ports are all matched, it still has the useful property of being lossless, and it simply dissipates the reflected power. The isolation resistor has a resistance of 100 omega.

When the antenna receives signals with right-hand equal amplitude and 90 degrees, the ports 2, 3, 4 and 5 receive the signals with equal amplitude, the phases are respectively-90 degrees, -180 degrees, -270 degrees and-360 degrees, the signals of the port 2 and the port 3 of the first electric bridge are combined into a signal phase of 0 degree at the port 6 and transmitted to the port 8 of the third electric bridge through the coaxial structure, and the signals of the port 4 and the port 5 of the second electric bridge are combined into a signal phase of-180 degrees at the port 7 and transmitted to the port 9 of the third electric bridge through the coaxial structure. The phase difference between the port 8 and the port 9 of the third bridge is 180 degrees, and finally the two paths of signals are synthesized and output at the port 1.

And each four equal-amplitude 90-degree network receiving sub-arrays realize signal synthesis output by cascading a four-in-one Wilkinson power synthesizer.

The system is applied to a phased array antenna system;

the working frequency band of the system is 19.6-21.2 GHz.

Fig. 4 shows a design structure after an equivalent grounding is realized by adopting 1/4 lambda sector metal to equivalently replace a grounding hole.

Fig. 5 shows a specific lamination diagram of a constant-amplitude 90 ° network, and specific in-layer positions of via holes and semi-conductive through holes are determined according to an actual lamination sequence, see fig. 6.

Fig. 7 shows that 1 port and 2 port, and a second metalized shielding hole is needed to be shared between interconnection ports (6 port and 8 port, 7 port and 9 port), when a circuit pattern is arranged below a through hole, an upper layer metalized hole is reserved according to the requirement of a laminated structure, and the upper layer metalized hole is changed into a semi-conductive through blind hole.

It is further noted here that the size of the pad ring required for different kinds of vias varies from process to process.

The blind holes (L1-L2) are from L1 to L2, are metallized, filled with metal and perforated before the first mixing and pressing. The pad ring width was 3 mils. (l1 to l2)

The buried holes (L2-L4) are buried holes from the L2 layer to the L4 layer, metallized holes are filled with metal, and back drilling and punching are carried out after the second mixed pressing. The pad ring width was 5 mils.

The blind holes (L4-L5) are from L4 layer to L5 blind holes, metallized holes, filled with metal, and punched before the second mixing and pressing. The pad ring width was 3 mils.

The blind holes (L1-L3) are from L1 layers to L3 layers, are metallized, filled with metal, punched after the first mixed pressing, and then mixed pressing is carried out.

In the back drilling residual shown in fig. 8, when the back drilling mode is used for drilling, and the depth of the back drilling residual end is 0.15mm, the simulation result shows that the design requirement is met, and meanwhile, the condition meets the processing requirement.

Fig. 9, fig. 10, fig. 11, fig. 12, fig. 13, and fig. 14 show simulation results after adding the SSMP model of the connector in the embodiment, in the operating frequency band of 19.6 to 21.2GHz, return loss of five input/output ports is lower than-15 dB, insertion loss is between-6.1 to-6.6 dB, isolation between 2, 3, 4, and 5 ports is smaller than-18 dB, phase difference between two adjacent ports is 90 °, phase imbalance is smaller than 0.5 °, return loss of wilkinson power combiner port is smaller than-18.8 dB, and insertion loss is about-6.4 dB, which all satisfy requirements.

Therefore, in the technical scheme in the embodiment of the invention, a plurality of bridges and power combiners form a feed network system in a three-dimensional stacked mode, so that the dispersion effect caused by using a phase shifting line is avoided. According to the embodiment of the invention, a symmetrical structural design is applied, the apertures of the through holes and the semi-conductive through holes and the sizes of the corresponding pad rings are reasonably set according to an actual processing technology, and the miniaturization and the high integration of the feed network can be realized. The design brings great flexibility and expandability, the scale can be adjusted according to actual needs, the requirements of system size, weight and universality are met, and the method has very wide application value and applicability technical effect.

Claims (8)

1. A feed network system comprises four equal-amplitude 90-degree network sub-arrays arranged in a rectangular array and a power synthesis network positioned at the bottom of the network sub-arrays; the equal-amplitude 90-degree network sub-arrays of the four arrays realize signal synthesis output by cascading a four-in-one Wilkinson power synthesizer; the constant-amplitude 90-degree network subarray is characterized by comprising a first metal grounding plate, a first microwave substrate, a first metal signal line, a first semi-solidified sheet, a second microwave substrate, a second metal grounding plate, a second semi-solidified sheet, a second metal signal line, a third microwave substrate and a third metal grounding plate which are sequentially stacked from top to bottom; microwave substrates are bonded through prepregs;

the first electric bridge and the second electric bridge in the constant-amplitude 90-degree network are both 90-degree electric bridges, and the ports of the first electric bridge and the second electric bridge are both positioned on one side of the corresponding edge of the constant-amplitude 90-degree network; wherein the third bridge is a 180 ° bridge; the first difference port and the second difference port of the first bridge and the third difference port and the fourth difference port of the second bridge are respectively connected with four feeding end points corresponding to the antenna; the first combined port of the first bridge is connected with the fifth difference port of the third bridge, and the second combined port of the second bridge is connected with the sixth difference port of the third bridge; the third combined port of the third bridge is used for outputting an antenna signal;

the first metal grounding plate is connected with the second metal grounding plate through the first metalized shielding hole; the first metal grounding plate is connected with the third metal grounding plate through the second metalized shielding hole, and the second metalized shielding hole penetrates through the second metal grounding plate.

2. The feed network system of claim 1, wherein said constant amplitude, 90 ° network is a symmetrical structure.

3. The feed network system of claim 1, wherein said antenna is a microstrip antenna; the feed network system is connected with four feed endpoints of the microstrip antenna through the SSMP connector; the constant-amplitude 90-degree network subarray is connected with the Wilkinson power synthesizer through an SSMP connector.

4. The feed network system of claim 1, wherein the first combined port of the first bridge and the fifth difference port of the third bridge are connected by corresponding second metallized rf holes; and the second combined port of the second electric bridge and the sixth difference port of the third electric bridge are connected through corresponding second metalized radio frequency holes.

5. The feed network system of claim 4, wherein the first and second differential ports of the first bridge and the third and fourth differential ports of the second bridge are connected to four corresponding feed terminals of the antenna through corresponding third metallized RF holes located above the respective ports; and the third combined port of the third bridge outputs an antenna signal through a fourth metallized radio frequency hole positioned below the third combined port.

6. The feed network system of claim 5, wherein the first differential port of the first bridge and the third combined port of the third bridge share a common second metallized shielding hole, and the third metallized rf hole and the fourth metallized rf hole are off-axis; and the axes of the upper-layer metallized radio frequency hole and the lower-layer metallized radio frequency hole are superposed and share the corresponding second metallized shielding hole.

7. The feed network system of claim 1, wherein the isolated ports of the first bridge, the second bridge and the third bridge are all implemented with sector-shaped metal to achieve equivalent grounding; the radius of the fan-shaped metal is a quarter wavelength.

8. The feed network system of claim 6, wherein the third metallized rf aperture is perforated prior to the first mixing and pressing, and the pad ring has a width of 3 mils;

the fourth metallized radio frequency hole is punched before the second mixed pressing, and the width of the welding disk ring is 3 mils;

and the second metallized radio frequency hole is drilled by back drilling after the second mixed pressing, and the width of the pad ring is 5 mils.

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