CN105896081A - Dual frequency electrically controlled reconfigurable butler matrix feed network - Google Patents

Abstract

A dual-frequency electronically controlled reconfigurable butler matrix feed network is mainly composed of a 90° electric bridge with dual-band characteristics, an electronically controlled reconfigurable 45° phase-shift matrix, a dual-band jumper connector and a switch matrix. The electronically controlled reconfigurable 45° phase shift matrix is switched to different frequencies by controlling the switch matrix, so that the butler matrix can be switched arbitrarily at two different operating frequencies, realizing reconfigurable operating frequencies. The electronically controlled reconfigurable butler matrix feeding network can be realized by planar printing technology, has a compact structure, and is suitable for small wireless communication systems.

Description

A Dual Frequency Electronically Controlled Reconfigurable Butler Matrix Feed Network

technical field

The invention belongs to the field of microwave engineering and relates to a matrix feeding network.

Background technique

With the rapid growth of wireless communication technology, the network capacity of the wireless communication system is greatly limited. In order to improve the utilization rate of spectrum resources and increase channel capacity, smart antennas have been widely used in satellite communication systems, personal communication systems and wireless local area networks and other systems.

At present, smart antennas are mainly divided into two types: adaptive antennas and multi-beam antennas, and multi-beam antennas have played an important role in the field of wireless communication due to their simple structure, flexible beam switching, and superior performance. The multi-beam forming network based on the butler matrix is the core component of the multi-beam antenna, which can effectively control the phase distribution of the antenna array, thereby realizing different beam directions.

The butler matrix feed network is usually composed of 3dB bridges, jumper connectors and phase shifters. Its working principle is that when each input port is excited, the input power is distributed to the output port in a certain proportion and in the adjacent There will be a specific phase difference between the output ports, but when the microwave energy is input from different input ports, the phase difference of the output ports will be different. Therefore, different phase differences can be obtained by stimulating different input ports, so that the beams of the antenna can be directed differently, and multiple beams can be realized. However, the traditional butler matrix is usually composed of 3dB bridges, jumper connectors, and fixed phase shifters that can only work in a single frequency band. Therefore, once the design is completed, it can only work in a single communication frequency band and cannot meet multiple frequency bands. work requirements, thus limiting the scope of application of the butler matrix.

Contents of the invention

The technical problem solved by the present invention is: aiming at that the existing butler matrix can only work in a single frequency band and cannot meet the requirements of multi-band gating work, a dual-frequency electronically controlled reconfigurable butler matrix feed network is proposed to realize Dual band strobe operation.

The technical solution of the present invention is: a dual-frequency electric control reconfigurable butler matrix feed network, including the first 90° electric bridge, the second 90° electric bridge, the third 90° electric bridge, the fourth 90° electric bridge Bridge, jumper connector, first electrically controlled reconfigurable 45° phase shift matrix, second electrically controlled reconfigurable 45° phase shift matrix, switch matrix, first bias circuit and second bias circuit; first Among the four ports of the 90° electric bridge, the two ports located on the same side below are used as the first and second input ports of the feed network; among the two ports located on the upper side, the left port is connected to the first The input terminal of the control reconfigurable 45° phase shift matrix is connected, and the right port is connected with the first input port on the left side of the lower part of the jumper connector; among the four ports of the third 90° electric bridge, the two ports on the same side above Two ports are used as the first output end and the second output end of the feed network, among the two ports on the lower side, the left port is connected to the output end of the first electronically controlled reconfigurable 45° phase shift matrix, and the right The port is connected to the second output port on the upper left side of the jumper connector; among the four ports of the second 90° electric bridge, the two ports on the same side below are used as the third input port and the fourth input port of the feed network , among the two ports on the upper side, the right port is connected to the input end of the second electronically controlled reconfigurable 45° phase shift matrix, and the left port is connected to the second input end on the lower right side of the jumper connector; Among the four ports of the fourth 90° electric bridge, the two ports on the same side above are used as the third output end and the fourth output end of the feed network; among the two ports on the lower side, the right port is the same as the The output terminals of the two electronically controlled reconfigurable 45° phase-shift matrices are connected, and the left port is connected to the first output terminal on the upper right side of the jumper connector; the jumper connector is connected to the first input through the jumper The signal at the end is output through the first output end, and the signal sent to the second input end is output through the second output end; the first 90° electric bridge, the second 90° electric bridge, the third 90° electric bridge, the fourth The 90° bridge has the same dual-band characteristics, the jumper connector has dual-band characteristics and the two operating frequency bands are the same as the first 90° bridge; the first electronically controlled reconfigurable 45° phase shift matrix , The second electronically controlled reconfigurable 45° phase shift matrix has the same dual-band characteristics, and gates can be respectively realized at the center frequency points of the two working frequency bands of the first 90° electric bridge, and the corresponding two working The phase shift at the center frequency point of the frequency band is 45°; the switch matrix is the control unit of the bias signal, and the bias signal of the switch matrix is sent to the first electronically controlled reconfigurable 45 through the first bias circuit respectively. °phase-shift matrix controls the working frequency band of the first electronically controlled reconfigurable 45°phase-shift matrix, and sends it to the second electronically controlled reconfigurable 45°phase-shift matrix through the second bias circuit to control the second electronically controlled reconfigurable 45° °The frequency band in which the phase shift matrix works.

The structure of the first electronically controlled reconfigurable 45° phase shift matrix and the second electrically controlled reconfigurable 45° phase shift matrix are the same, both of which are composed of two microstrip lines of different lengths, and the two microstrip lines The electrical lengths respectively correspond to one-eighth wavelengths of the center frequency points of the two working frequency bands of the first 90° electric bridge.

The jumper connector described is a dual-band jumper connector, and the signal transmission lines therein are implemented in the form of microstrip lines.

The structures of the first 90° electric bridge, the second 90° electric bridge, the third 90° electric bridge, and the fourth 90° electric bridge are the same, all of which are dual-band 90° electric bridges, and the signal transmission lines all adopt micro Realized in wired form.

The advantage of the present invention compared with prior art is:

1) The dual-frequency electronically controlled reconfigurable butler matrix feeder network of the present invention can arbitrarily select and work on two operating frequency bands, and the two operating frequency bands do not interfere with each other;

2) The 90° electric bridge in the present invention is a dual-band device, which can work in two frequency bands simultaneously, and has better isolation between the two frequency bands;

3) The jumper connector of the present invention adopts a dual-band design, which can work in two frequency bands at the same time, and the isolation between the two frequency bands is high;

4) The electronically controlled reconfigurable 45° phase-shift matrix structure adopted in the present invention can be conveniently arbitrarily selected between two frequency bands;

5) The present invention uses a switch matrix to uniformly control the gating of the working frequency band, and has the characteristics of fast switching speed and easy operation.

Description of drawings

Fig. 1 is the schematic diagram of the electrical control reconfigurable butler matrix feeding network of the present invention;

Fig. 2 is a schematic diagram of the top structure of an electronically controlled reconfigurable butler matrix feed network in an embodiment of the present invention;

3 is a schematic diagram of the bottom structure of the electronically controlled reconfigurable butler matrix feed network in an embodiment of the present invention;

Fig. 4 is a side view of an electronically controlled reconfigurable butler matrix feeder network in an embodiment of the present invention;

Fig. 5 is the schematic diagram of 90 ° electric bridge in the embodiment of the present invention;

6 is a schematic diagram of a jumper connector in an embodiment of the present invention;

Fig. 7 is the insertion loss characteristic of the port when the excitation signal is fed by p1 when the gate is at 2.5 GHz in the embodiment of the present invention;

Fig. 8 is the insertion loss characteristic of the port when the excitation signal is fed by p1 when the gate is at 5.2 GHz in the embodiment of the present invention;

Fig. 9 is the insertion loss characteristic of the port when the excitation signal is fed by p2 when the gate is at 2.5 GHz in the embodiment of the present invention;

FIG. 10 shows the insertion loss characteristics of the port when the excitation signal is fed by p2 when the gate is at 5.2 GHz in the embodiment of the present invention.

detailed description

The dual-frequency electronically controlled reconfigurable butler matrix feeding network of the present invention is composed of a 90° electric bridge with dual frequency band characteristics, a jumper connector and an electronically controlled reconfigurable 45° phase shift matrix. The 45° transmission lines operating in different frequency bands in the electronically controlled reconfigurable phase shift matrix are gated through the switch matrix, so as to control the feed network to work at different frequencies.

As shown in Figure 1, the butler matrix feed network of the present invention mainly includes: four input terminals p1, p2, p3 and p4, four output terminals p5, p6, p7 and p8, 90° electric bridge 1, 90° electric bridge 2, 90° bridge 3, 90° bridge 4, jumper connector 5, electronically controlled reconfigurable 45° phase shift matrix 6, electronically controlled reconfigurable 45° phase shift matrix 7, switch matrix 8, bias circuit 9 and bias circuit 10.

Port ① of 90° electric bridge 1 is connected to port ⑤ of electronically controlled reconfigurable 45° phase shift matrix 6, and port ④ of 90° electric bridge 2 is connected to port ⑧ of electronically controlled reconfigurable 45° phase shift matrix 7. Port of 90° bridge 3 Connect with the port ⑨ of the electronically controlled reconfigurable 45° phase shift matrix 6, and the port 4 of the 90° electric bridge Ports with electronically controlled reconfigurable 45° phase shift matrix 7 connect. Port ⑥ of jumper connector 5 is connected to port ② of 90° electric bridge 1, port ⑦ of jumper connector 5 is connected to port ③ of 90° electric bridge 2, port ⑩ of jumper connector 5 is connected to port ② of 90° electric bridge port of bridge 3 connection, jumper the port of connector 5 4 ports with 90° bridge connect.

Further, the 90° electric bridge 1, the 90° electric bridge 2, the 90° electric bridge 3, and the 90° electric bridge 4 have the same structure, all are 3dB 90° electric bridges, and can work in two frequency bands. Take 90° electric bridge 1 as an example, if the signal is input by port p1, then port 1 and port 2 will output two signals with equal amplitude and 90° phase difference in the two working frequency bands, and port p2 is isolated; if the signal is input by port p2 input, then port 1 and port 2 output two signals with equal amplitude and 90° phase difference on the two working frequency bands, and port p2 is isolated; if the signal is input by port 1, port p1 and port p2 work in two Two signals with equal amplitude and 90° phase difference are output on both frequency bands, and port 2 is isolated; if the signal is input from port 2, port p1 and port p2 output two signals with equal amplitude and 90° phase difference on the two working frequency bands. Road signal, port 1 is isolated.

Furthermore, the jumper connector 5 has a dual-band characteristic, which can simultaneously realize the excitation signal entering and exiting through the port 6 and outputting through the port 11 in two frequency bands, and having no signal output through the ports 7 and 10. It can also realize that the excitation signal enters and exits through port 7, outputs through port 10, and has no signal output through port 6 and port 11. Furthermore, the two frequency bands in which the jumper connector 5 operates are the same as the two frequency bands in which the 90° bridge 1 operates.

Further, the electronically controlled reconfigurable 45° phase shift matrix 6 and the electronically controlled reconfigurable 45° phase shift matrix 7 have the same structure, and at the center frequency points of the two working frequency bands corresponding to the 90° electric bridge 1, the electronically controlled The reconfigurable 45° phase shift matrix 6 can respectively realize gating characteristics, and the phase shifts at the center frequency points of the corresponding two working frequency bands are both 45°. The electronically controlled reconfigurable 45° phase-shift matrix 7 can also realize gating characteristics at the center frequency points of the two working frequency bands corresponding to the 90° electric bridge 1, and the corresponding two working frequency band center frequency points The phase shift amounts are also 45°. In addition, the electrically controlled reconfigurable 45° phase shift matrix 6 and the electrically controlled reconfigurable 45° phase shift matrix 6 must be gated at the center frequency point of the same working frequency band.

Further, the switch matrix 8 is a bias signal control unit, which contains multiple groups of controllable switches, and controls the on-off of the controllable switches according to the requirements, so that it has the function of selectively applying the bias signal to the bias circuit. The bias signal of the switch matrix 8 is transmitted to the electrically controlled reconfigurable 45° phase shift matrix 6 and the electrically controlled reconfigurable 45° phase shift matrix 7 through the bias circuit 9 and the bias circuit 10 respectively. Under the control of the same bias signal of the switch matrix 8, the electronically controlled reconfigurable 45° phase shift matrix 6 and the electrically controlled reconfigurable 45° phase shift matrix 7 are simultaneously gated at the center frequency point of the same working frequency band, And produce a phase shift of 45°.

Further, when each input port is excited, firstly, by controlling the electronically controlled reconfigurable 45° phase shift matrix, and gating at the required operating frequency, the signal energy will be transferred to the output port by quartering, and A constant phase difference will result between adjacent output ports, but the output port signals will have different phase differences when excited from different input ports. In this way, different input ports can be excited to obtain different phase differences, and beams of different directions can be obtained when the array antenna is excited.

Example

It is assumed that the dual-frequency electronically controlled reconfigurable butler matrix feeder network of the present invention can be switched arbitrarily at two operating frequencies of 2.5GHz and 5.2GHz, and is implemented in the form of a printed circuit board.

As shown in FIG. 2 , FIG. 3 , and FIG. 4 , the dielectric substrate 11 includes a metal copper-clad top layer, a dielectric layer, a metal copper-clad middle layer, a dielectric layer, and a metal copper-clad bottom layer from top to bottom. The dielectric constant of the dielectric layer is selected as 2.65, and the thickness is 1 mm. 90° electric bridge 1, 90° electric bridge 2, 90° electric bridge 3, 90° electric bridge 4, jumper connector 5, electric control and reconfigurable 45° phase shift matrix 6, electric control can Reconstruct the 45° phase shift matrix7. The metal copper-clad bottom layer is installed with a switch matrix 8, and the bias circuit connects the bias connection line of the metal copper-clad top layer to the bias connection of the metal copper-clad bottom layer through metal pillars a1-b1, a2-b2, a3-b3, a4-b4 respectively The wires are connected, and the diameter of the metal post is 1mm. The ground wire 12 is connected to the copper-clad metal middle layer through the metallized via hole a5, and the diameter of the metallized via hole is 1.5 mm.

The electronically controlled reconfigurable 45° phase shift matrix 6 and the electronically controlled reconfigurable 45° phase shift matrix 7 have the same structure, and both are composed of two microstrip lines with different lengths. The longer microstrip line in the electronically controlled reconfigurable 45° phase shift matrix 6 is connected to the 90° bridge 1 and 90° bridge 3 through the switching diodes v1 and v2, and in the electrically controlled reconfigurable 45° phase shift matrix 6 The shorter microstrip line is connected to the 90° bridge 1 and 90° bridge 3 through switching diodes v3 and v4, and the longer microstrip line in the electronically controlled reconfigurable 45° phase shift matrix 7 passes through switching diodes v5 and v6 Connected with 90° electric bridge 2 and 90° electric bridge 4, the shorter microstrip line in electronically controlled reconfigurable 45° phase shift matrix 7 passes through switching diodes v7, v8 and 90° electric bridge 2, 90° electric bridge 4 connect. The electrical lengths of the two microstrip lines correspond to one-eighth of the wavelength of the center frequency points of the two operating frequency bands of the 90° bridge 1 respectively, and a phase shift of 45° can be formed at both frequency points. Increase the bias voltage to the bias circuit through the switch matrix 8, gate the longer microstrip line and the input and output in the electrically controlled reconfigurable 45° phase shift matrix 6 and the electrically controlled reconfigurable 45° phase shift matrix 7 Port gating, can make the butler matrix feed network work at 2.5GHz. Add the bias voltage to the bias circuit through the switch matrix 8, gate the short microstrip line and the input and output ports in the electronically controlled reconfigurable 45° phase shift matrix 6 and the electronically controlled reconfigurable 45° phase shift matrix 7 Strobe, can make the butler matrix feed network work at 5.2GHz.

90° electric bridge 1, 90° electric bridge 2, 90° electric bridge 3, and 90° electric bridge 4 have the same structure, and they are all dual-band 90° electric bridges. As shown in FIG. 5 , the dual-band 90° electric bridge is composed of four input and output transmission lines 111 , two transmission lines 112 , two transmission lines 113 , four stub loading transmission lines 114 and four fan-shaped transmission line structures 115 . The above transmission lines are all implemented in the form of microstrip lines. Both the transmission 112 and the transmission 113 adopt a bent line structure, which can effectively reduce the size.

The jumper connector 5 is a dual-band jumper connector, and its two working frequency bands are the same as those of the 90° electric bridge 1 . As shown in Figure 6, the dual-band jumper connector includes four input and output transmission lines 121, two transmission lines 122, two transmission lines 123, one transmission line 124, four end stub loading transmission lines 125, two stub loading transmission lines 126, four fan-shaped The transmission line structure 127 is composed of two fan-shaped transmission line structures 128 . The above transmission lines are all implemented in the form of microstrip lines. The transmission line 122, the transmission line 123 and the transmission line 124 all adopt a bent line structure, which can effectively reduce the size.

The dual-frequency electronically controlled reconfigurable butler matrix feeding network of the present invention is simulated, and Fig. 7 shows the insertion of the output ports p5, p6, p7 and p8 when the excitation signal is fed through the p1 port when the feeding network is gated at 2.5 GHz loss characteristics. As shown in the figure, the amplitude consistency at 2.5 GHz is good, which meets the requirement of signal equalization. Figure 8 shows the insertion loss characteristics of the output ports p5, p6, p7 and p8 when the feed network is gated at 5.2 GHz and the excitation signal is fed from the p1 port. As shown in the figure, the amplitude consistency at 5.2GHz meets the equal division requirement. Table 1 shows the phase characteristics of the output ports p5, p6, p7 and p8 at different frequencies when the excitation signal is fed by the p1 port. When the feed network is gated at 2.5GHz, the phase difference consistency at 2.5GHz≤ 3°, while the phase difference at 5.2GHz is not fixed. When the feeding network is gated at 5.2GHz, the amplitude difference at 2.5GHz is not constant, but the phase difference at 5.2GHz is ≤3°.

Table 1. Output port phase characteristics at 2.5GHz

Figure 9 shows the insertion loss characteristics of the output ports p5, p6, p7 and p8 when the feed network is gated at 2.5 GHz and the excitation signal is fed from the p2 port. As shown in the figure, the amplitude consistency at 2.5 GHz is good, which meets the requirement of signal equalization. Figure 10 shows the insertion loss characteristics of the output ports p5, p6, p7 and p8 when the feed network is gated at 5.2 GHz and the excitation signal is fed from the p2 port. As shown in the figure, the amplitude consistency at 5.2GHz meets the equal division requirement. Table 2 shows the phase characteristics of the output ports p5, p6, p7 and p8 at different frequencies when the excitation signal is fed by the p2 port. When the feed network is gated at 2.5GHz, the phase difference consistency at 2.5GHz≤ 3°, while the phase difference at 5.2GHz is not fixed. When the feeding network is gated at 5.2GHz, the amplitude difference at 2.5GHz is not constant, but the phase difference at 5.2GHz is ≤3°.

Table 2 Gate at 5.2GHz output port phase characteristics

The dual-frequency electronically controlled reconfigurable butler matrix feeding network of the present invention is not limited to a specific working frequency, for example, it can be switched arbitrarily between two working frequencies of 2.5GHz and 5.2GHz.

The content that is not described in detail in the description of the present invention belongs to the well-known technology of those skilled in the art.

Claims (4)

1. A dual-frequency electronically controlled reconfigurable butler matrix feed network is characterized in that it comprises: the first 90 ° electric bridge (1), the second 90 ° electric bridge (2), the third 90 ° electric bridge (3 ), the fourth 90° electric bridge (4), the jumper connector (5), the first electrically controlled reconfigurable 45° phase shift matrix (6), the second electrically controlled reconfigurable 45° phase shift matrix (7 ), a switch matrix (8), a first bias circuit (9) and a second bias circuit (10); among the four ports of the first 90° electric bridge (1), the two ports located on the same side below are used as The first input end and the second input end of the feed network are located in the two ports on the upper side, the left port is connected to the input end of the first electronically controlled reconfigurable 45° phase shift matrix (6), and the right side The ports are connected to the first input end on the lower left side of the jumper connector (5); among the four ports of the third 90° electric bridge (3), the two ports on the same side above are used as the first output of the feed network terminal and the second output terminal, in the two ports on the lower side, the left port is connected with the output terminal of the first electronically controlled reconfigurable 45° phase shift matrix (6), and the right port is connected with the jumper connector ( 5) is connected to the second output terminal on the upper left side; among the four ports of the second 90° electric bridge (2), the two ports on the same side below are used as the third input terminal and the fourth input terminal of the feed network, Among the two ports on the upper side, the right port is connected to the input end of the second electronically controlled reconfigurable 45° phase shift matrix (7), and the left port is connected to the lower right port of the jumper connector (5). The two input ends are connected; among the four ports of the fourth 90° electric bridge (4), the two ports on the same side above are used as the third output end and the fourth output end of the feed network, and the two ports on the lower side are used as Among the ports, the right port is connected to the output end of the second electronically controlled reconfigurable 45 ° phase shift matrix (7), and the left port is connected to the first output end on the top right side of the jumper connector (5); the The jumper connector (5) sends the signal sent into the first input end through the first output end through the jumper, and outputs the signal sent into the second input end through the second output end; the first 90° electric bridge (1), the second 90 ° electric bridge (2), the third 90 ° electric bridge (3), the fourth 90 ° electric bridge (4) have the same dual-band characteristics, and the jumper connector (5) has Dual-band characteristics and the two operating frequency bands are the same as the first 90° electric bridge (1); the first electrically controlled reconfigurable 45° phase shift matrix (6), the second electrically controlled reconfigurable 45° phase shift The matrix (7) has the same dual-band characteristics, and gates can be respectively realized at the center frequency points of the two working frequency bands of the first 90° electric bridge (1), and at the center frequency points of the corresponding two working frequency bands The amount of phase shift is 45 °; the switch matrix (8) is the control unit of the bias signal, and the bias signal of the switch matrix (8) is sent to the first electric control can be respectively through the first bias circuit (9). The reconfigurable 45° phase shift matrix (6) controls the working frequency band of the first electronically controlled reconfigurable 45° phase shift matrix (6), and sends it to the second electronically controlled reconfigurable 45° through the second bias circuit (10). The phase shift matrix (7) controls the second electric control The frequency band in which the 45° phase shift matrix (7) works can be reconfigured. 2. A kind of dual-frequency electronically controlled reconfigurable butler matrix feed network according to claim 1, characterized in that: the first electronically controlled reconfigurable 45° phase shift matrix (6) and the second electrically controlled The control reconfigurable 45° phase shift matrix (7) has the same structure, both of which are composed of two microstrip lines of different lengths, and the electrical lengths of the two microstrip lines correspond to the two of the first 90° electric bridge (1) One-eighth wavelength of the center frequency point of the working frequency band. 3. A kind of dual-frequency electronically controlled reconfigurable butler matrix feeder network according to claim 1 or 2, characterized in that: said jumper connector (5) is a dual-band jumper connector, wherein The signal transmission lines are implemented in the form of microstrip lines. 4. a kind of double-frequency electric control reconfigurable butler matrix feeding network according to claim 1 or 2, is characterized in that: described first 90 ° electric bridge (1), the second 90 ° electric bridge ( 2), the structure of the third 90° electric bridge (3) and the fourth 90° electric bridge (4) are the same, both are dual-band 90° electric bridges, and the signal transmission lines are implemented in the form of microstrip lines.