Ka-band Satellite Communication Phased Array Antenna Feeding Network with Enhanced Transmit-Receive Isolation

Abstract

The present invention discloses a Ka-band satellite communication phased array antenna feed network for enhancing transceiver isolation, which consists of a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line and a coupling line to form a ring circuit, and a first short circuit line, a second short circuit line, a third short circuit line, a fourth short circuit line, a fifth short circuit line, a sixth short circuit line and a seventh short circuit line connected to the ring circuit. The feed network structure of the present invention is applicable to the Ka-band satellite communication phased array antenna, and has the advantages of compact structure and effectively suppressing the noise of the uplink transmitter falling on the downlink receiving frequency band.

Description

Technical Field

[0001] The present invention relates to a Ka-band satellite communication phased array antenna feed network for enhancing transceiver isolation, and belongs to the technical field of satellite communication. Background Art

[0002] In recent years, the successful application of low-earth orbit satellite communication has made it a current research hotspot. The Ka band is one of the key frequency bands for low-earth orbit satellite communication. Generally, 27.5 - 31 GHz is used as the uplink transmission frequency band, and 17.7 - 21 GHz is used as the downlink reception frequency band. This frequency band has rich bandwidth resources, can provide larger communication capacity and higher transmission rate, and is especially suitable for large data volume and high-speed broadband communication requirements. The Ka-band phased array antenna has broad application prospects because it can achieve fast beam switching, fast satellite tracking, and has strong anti-interference ability.

[0003] At present, satellite communication mainly adopts a full-duplex system, that is, the satellite and the ground terminal transmit and receive simultaneously. This poses a great challenge to the phased array antenna system. In the full-duplex system, transceiver isolation is an important index restricting the system performance. On the one hand, the system design needs to effectively suppress the signal leaked from the satellite transmitter to the receiving link to avoid blocking the receiving channel. On the other hand, the system design needs to effectively suppress the wide-spectrum noise of the ground transmitter (especially the noise falling into the downlink reception frequency band) to avoid significantly deteriorating the noise performance of the ground receiver, thus affecting the received signal-to-noise ratio. The above transceiver isolation is relatively easy to solve in the traditional parabolic antenna satellite communication system, that is, a low-loss waveguide filter is added at the front end of the ground receiver to filter out the transmitted leakage signal, and a band-pass filter for suppressing the transmitted wide-spectrum noise is added at the front end of the ground transmitter to avoid noise leakage to the ground receiver.

[0004] However, for a highly integrated phased array antenna system, it is obviously unrealistic to use large-sized and bulky waveguide filters. Using microstrip filters has problems such as large losses, resulting in unnecessary power loss. And if effective suppression is to be achieved, the size of the microstrip filter is sometimes unacceptable.

[0005] The feed network is one of the core circuits of the phased array antenna, which completes the function of distributing the input radio frequency signal or collecting the received signal. How to use the feed network to solve the problem of transceiver isolation in the Ka-band low-earth orbit full-duplex satellite communication phased array antenna system is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0006] Objective: To overcome the problem of the deterioration of the receiver performance caused by the noise of the uplink transmitter falling in the downlink receiving frequency band in the prior art, the present invention provides a Ka-band satellite communication phased array antenna feeding network for enhancing transceiver isolation. This structure can be used for the transmitting feeding network. While completing signal distribution, it can effectively suppress the wide-spectrum noise falling in the receiving frequency band, effectively relieve the transceiver isolation pressure of the full-duplex phased array antenna system, and thus meet the requirements of the Ka-band satellite communication array antenna transmitter in engineering applications.

[0007] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A Ka-band satellite communication array antenna feeding network structure includes: a ring circuit composed of a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line and a coupling line, and a first short-circuit line, a second short-circuit line, a third short-circuit line, a fourth short-circuit line, a fifth short-circuit line, a sixth short-circuit line and a seventh short-circuit line connected to the ring circuit.

[0009] Optionally, the first microstrip line, the second microstrip line, the third microstrip line, the fourth microstrip line, the fifth microstrip line and the sixth microstrip line are sequentially connected end to end through wires. The coupling line includes a first coupling line and a second coupling line. The other end of the first microstrip line is connected to one end of the first coupling line through a wire, and the other end of the sixth microstrip line is connected to one end of the second coupling line through a wire.

[0010] A first short-circuit line is connected between the first microstrip line and the first coupling line through a wire, a second short-circuit line is connected between the first microstrip line and the second microstrip line through a wire, a third short-circuit line is connected between the second microstrip line and the third microstrip line through a wire, a fourth short-circuit line is connected between the third microstrip line and the fourth microstrip line through a wire, a fifth short-circuit line is connected between the fourth microstrip line and the fifth microstrip line through a wire, a sixth short-circuit line is connected between the fifth microstrip line and the sixth microstrip line through a wire, and a seventh short-circuit line is connected between the sixth microstrip line and the second coupling line through a wire.

[0011] Optionally, the other ends of the first short-circuit line, the second short-circuit line, the third short-circuit line, the fourth short-circuit line, the fifth short-circuit line, the sixth short-circuit line, the seventh short-circuit line, the first coupling line and the second coupling line are all connected to the ground.

[0012] Optionally, an input port is provided between the second microstrip line and the third microstrip line, a first output port is provided between the first microstrip line and the first coupling line, and a second output port is provided between the fourth microstrip line and the fifth microstrip line.

[0013] Optionally, the first microstrip line, the second microstrip line, the third microstrip line, the fourth microstrip line, the fifth microstrip line, and the sixth microstrip line have the same line length and line width.

[0014] Optionally, the first coupling line and the second coupling line have the same line length and line width.

[0015] Optionally, the first short circuit line, the second short circuit line, the third short circuit line, the fourth short circuit line, the fifth short circuit line, the sixth short circuit line, and the seventh short circuit line have the same line length. The second short circuit line, the third short circuit line, the fifth short circuit line, and the sixth short circuit line have the same line width. The first short circuit line and the seventh short circuit line have the same line width. The line widths of the first short circuit line, the second short circuit line, and the fourth short circuit line increase in sequence.

[0016] Optionally, a load is grounded between the sixth microstrip line and the second coupling line.

[0017] Optionally, the feeding network is disposed on a substrate.

[0018] Beneficial effects: The feeding network of the Ka-band satellite communication phased array antenna for enhancing the transceiver isolation provided by the present invention is applicable to the Ka-band satellite communication phased array antenna. It has the advantages of a compact structure and can effectively suppress the noise of the uplink transmitter falling on the downlink receiving frequency band.

[0019] The feeding network of the Ka-band satellite communication phased array antenna for enhancing the transceiver isolation provided by the present invention effectively realizes the feeding function of the Ka-band satellite communication array antenna. At the same time, the unique structural design effectively suppresses the noise of the Ka-band satellite communication uplink transmitter falling on the downlink receiving frequency band and can meet the requirements of the current Ka-band satellite communication array antenna feeding network. Compared with the prior art, the advantages of the present invention are as follows:

[0020] 1. The wideband noise will increase the noise floor of the downlink receiver of the satellite communication array antenna, resulting in a cliff-like drop in the system capacity and also polluting adjacent frequency bands. The feeding network structure of the Ka-band satellite communication array antenna provided by the present invention effectively suppresses the noise in the downlink receiving frequency band (i.e., 17.7 - 21.2 GHz) in the uplink transmitting feeding network part, effectively reducing the receiver noise floor.

[0021] 2. Currently, the common solutions for suppressing wideband noise in Ka-band satellite communication array antennas, such as high-frequency band-pass filters (BPF), usually require multiple stages of filtering to meet the requirements of high quality factor (Q value) and have a large size. The feeding network structure of the Ka-band satellite communication array antenna provided by the present invention suppresses the noise of the uplink transmitter falling on the downlink receiving frequency band while completing the feeding function of the satellite communication array antenna transmitter, making the structure more compact. Description of the Drawings

[0022] Figure 1 This is a schematic diagram of the feeding network structure of the Ka - band satellite communication array antenna of the present invention.

[0023] Figure 2 This is the simulation result diagram of the conduction effect of the Wilkinson power divider in the comparative example. Among them, Figure 2 Figure (a) in it is a schematic diagram of the relationship between the transmission coefficient of the first output port and frequency. Figure 2 Figure (b) in it is a schematic diagram of the relationship between the transmission coefficient of the second output port and frequency.

[0024] Figure 3 This is the simulation result diagram of the conduction and suppression effects of the feeding network structure of the array antenna in the specific embodiment. Among them, Figure 3 Figure (a) in it is a schematic diagram of the relationship between the transmission coefficient of the first output port and frequency. Figure 3 Figure (b) in it is a schematic diagram of the relationship between the transmission coefficient of the second output port and frequency.

[0025] Figure 4 This is a schematic diagram of the basic structure of the band - stop filter. Specific Embodiments

[0026] Next, in combination with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0027] Next, the present invention will be further described in combination with specific embodiments.

[0028] Embodiment 1:

[0029] This embodiment introduces a feeding network structure of a Ka - band satellite communication array antenna. As Figure 1 shown, it includes: a ring circuit composed of a first microstrip line 1, a second microstrip line 2, a third microstrip line 3, a fourth microstrip line 4, a fifth microstrip line 5, a sixth microstrip line 6 and a coupling line 7, and first short - circuit lines 12, second short - circuit lines 13, third short - circuit lines 14, fourth short - circuit lines 15, fifth short - circuit lines 16, sixth short - circuit lines 17, and seventh short - circuit lines 18 connected to the ring circuit. By cooperating the ring circuit with the seven - segment short - circuit lines, while realizing signal feeding, the function of the band - stop filter is also completed, which is used to suppress the signals in the downlink receiving frequency band.

[0030] Further, in one embodiment, the first microstrip line 1, the second microstrip line 2, the third microstrip line 3, the fourth microstrip line 4, the fifth microstrip line 5, and the sixth microstrip line 6 are sequentially connected end to end through wires. The coupled line 7 includes a first coupled line 701 and a second coupled line 702. The other end of the first microstrip line 1 is connected to one end of the first coupled line 701 through a wire, and the other end of the sixth microstrip line 6 is connected to one end of the second coupled line 702 through a wire.

[0031] A first short - circuit line 12 is connected between the first microstrip line 1 and the first coupled line 701 through a wire. A second short - circuit line 13 is connected between the first microstrip line 1 and the second microstrip line 2 through a wire. A third short - circuit line 14 is connected between the second microstrip line 2 and the third microstrip line 3 through a wire. A fourth short - circuit line 15 is connected between the third microstrip line 3 and the fourth microstrip line 4 through a wire. A fifth short - circuit line 16 is connected between the fourth microstrip line 4 and the fifth microstrip line 5 through a wire. A sixth short - circuit line 17 is connected between the fifth microstrip line 5 and the sixth microstrip line 6 through a wire. A seventh short - circuit line 18 is connected between the sixth microstrip line 6 and the second coupled line 702 through a wire.

[0032] Further, in one embodiment, the other ends of the first short - circuit line 12, the second short - circuit line 13, the third short - circuit line 14, the fourth short - circuit line 15, the fifth short - circuit line 16, the sixth short - circuit line 17, the seventh short - circuit line 18, the first coupled line 701, and the second coupled line 702 are all connected to the ground.

[0033] Further, in one embodiment, an input port 8 is provided between the second microstrip line 2 and the third microstrip line 3. A first output port 9 is provided between the first microstrip line 1 and the first coupled line 701. A second output port 10 is provided between the fourth microstrip line 4 and the fifth microstrip line 5.

[0034] Further, in one embodiment, the first microstrip line 1, the second microstrip line 2, the third microstrip line 3, the fourth microstrip line 4, the fifth microstrip line 5, and the sixth microstrip line 6 have the same line length and line width.

[0035] Further, in one embodiment, the first coupled line 701 and the second coupled line 702 have the same line length and line width.

[0036] Further, in one embodiment, the first short - circuit line 12, the second short - circuit line 13, the third short - circuit line 14, the fourth short - circuit line 15, the fifth short - circuit line 16, the sixth short - circuit line 17, and the seventh short - circuit line 18 have the same line length. The second short - circuit line 13, the third short - circuit line 14, the fifth short - circuit line 16, and the sixth short - circuit line 17 have the same line width. The first short - circuit line 12 and the seventh short - circuit line 18 have the same line width. The line widths of the first short - circuit line 12, the second short - circuit line 13, and the fourth short - circuit line 15 increase in sequence.

[0037] Further, in one embodiment, the sixth microstrip line 6 is grounded through a load 11 between the second coupling line 702.

[0038] Further, in one embodiment, the feeding network is disposed on a substrate.

[0039] Embodiment 2

[0040] This embodiment introduces a specific embodiment of a feeding network for a Ka-band satellite communication array antenna. The line widths of the first microstrip line 1, the second microstrip line 2, the third microstrip line 3, the fourth microstrip line 4, the fifth microstrip line 5, and the sixth microstrip line 6 are all 1.1 mm, and the line lengths are all 0.66 mm, so as to form six microstrip lines with a length of one-eighth of the operating wavelength and an impedance of 75 ohms each.

[0041] The line widths of the first coupling line 701 and the second coupling line 702 are 1.5 mm, the line length is 4.25 mm, and the coupling line spacing is 1.44 mm, so as to form a coupling line with a length of one-quarter of the operating wavelength and odd-mode and even-mode impedances of 90 ohms and 62.5 ohms respectively.

[0042] The impedances of the input port 8, the first output port 9, the second output port 10, and the load 11 are the same, and are all 50 ohms.

[0043] The line widths of the second short-circuit line 13, the third short-circuit line 14, the fifth short-circuit line 16, and the sixth short-circuit line 17 are all 1.1 mm, and the line lengths are all 1.33 mm, so as to form four short-circuit lines with a length of one-quarter of the operating wavelength and an impedance of 75 ohms each.

[0044] The line widths of the first short-circuit line 12 and the seventh short-circuit line 18 are both 0.6 mm, and the line lengths are both 1.33 mm, so as to form two short-circuit lines with a length of one-quarter of the operating wavelength and an impedance of 100 ohms each to complete impedance matching.

[0045] The line width of the fourth short-circuit line 15 is 3.0 mm, and the line length is 1.33 mm, so as to form a short-circuit line with a length of one-quarter of the operating wavelength and an impedance of 50 ohms to maintain the symmetry of the circuit.

[0046] The output signal powers of the first output port 9 and the second output port 10 are equal, both being half of the input signal power of the input port 8, and the phases are the same.

[0047] The transmitting frequency of the Ka-band satellite communication array antenna is about 30 GHz, and the receiving frequency is about 20 GHz. The feeding network is designed based on one-third of the transmitting frequency as the reference frequency (the reference frequency is 10 GHz, corresponding to the operating wavelength). The dielectric constant of the substrate used in this embodiment is 4.3.

[0048] Embodiment 3:

[0049] This embodiment describes the simulation experiment of the output signals of the feed network of the present invention and the comparative example, specifically as follows:

[0050] The comparative example uses a Wilkinson power divider, which is a common feed network for satellite communication array antennas. As Figure 2 shown, for the S-parameter simulation results of the comparative example, the transmission coefficients of the two output ports are both above -5 dB in the frequency band of 27.5 - 31 GHz, achieving the required feeding function. However, the transmission coefficients of the two output ports are above -8 dB in the frequency band of 17.7 - 21 GHz, without obvious suppression effect.

[0051] The first output port 9 and the second output port 10 of the present invention both have a transmission coefficient above -5 dB in the frequency band of 27.5 - 31 GHz, and at the same time both have a transmission coefficient below -25 dB in the frequency band of 17.7 - 21 GHz, with an obvious suppression effect. As Figure 3 can be seen, this embodiment realizes the required feeding function and the required suppression function.

[0052] As Figure 4 shown, within the Ka-band satellite communication frequency band, the six microstrip lines are all one-eighth of the operating wavelength at the reference frequency, and are all one-quarter of the wavelength in the downlink receiving frequency band (17.7 - 21 GHz). The seven short-circuited lines are all one-quarter of the wavelength at the reference frequency, and are all half of the wavelength in the downlink receiving frequency band (17.7 - 21 GHz), approximately equivalent to seven series LC resonators, and are connected to the ring circuit at intervals of one-quarter of the wavelength, forming a basic structure of a band-stop filter to realize the suppression function of the signals in the downlink receiving frequency band (17.7 - 21 GHz). Since the seven short-circuited lines are all three-eighths of the wavelength in the uplink transmitting frequency band (27.5 - 31 GHz), they are equivalent to open circuits at the access points and have no influence on the transmitted signals, realizing the conduction function of the signals in the uplink transmitting frequency band (27.5 - 31 GHz).

[0053] Based on the above simulation results, it can be seen that within the Ka-band satellite communication frequency band, this embodiment can effectively complete the feeding function of the array antenna uplink transmitter, and at the same time effectively suppress the noise of the uplink transmitter falling in the downlink receiving frequency band (17.7 - 21 GHz), and can effectively meet the requirements of the Ka-band satellite communication array antenna for the feed network and wide-spectrum noise suppression, providing reliable key device support for future Ka-band satellite communication systems.

[0054] The above description is only an implementation manner of the present invention when the uplink transmission frequency is about 30 GHz and the downlink reception frequency is about 20 GHz. It should be noted that for full-duplex communication systems with similar frequency relationships, that is, full-duplex communication systems with a transceiver frequency ratio of about 2:3, several improvements and refinements can be made with reference to the network structure provided by the present invention, and these improvements and refinements should also be regarded as the protection scope of the present invention.

[0055] The above description is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. Ka-band satellite communication phased array antenna feed network with enhanced transceiver isolation, characterized in that Including: An annular circuit composed of a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line and a coupling line, and a first short circuit line, a second short circuit line, a third short circuit line, a fourth short circuit line, a fifth short circuit line, a sixth short circuit line, a seventh short circuit line connected to the annular circuit; The first microstrip line, the second microstrip line, the third microstrip line, the fourth microstrip line, the fifth microstrip line, and the sixth microstrip line are connected end to end in sequence through wires. The coupling line includes a first coupling line and a second coupling line. The other end of the first microstrip line is connected to one end of the first coupling line through a wire, and the other end of the sixth microstrip line is connected to one end of the second coupling line through a wire; A first short circuit line is connected between the first microstrip line and the first coupling line through a wire, a second short circuit line is connected between the first microstrip line and the second microstrip line through a wire, a third short circuit line is connected between the second microstrip line and the third microstrip line through a wire, a fourth short circuit line is connected between the third microstrip line and the fourth microstrip line through a wire, a fifth short circuit line is connected between the fourth microstrip line and the fifth microstrip line through a wire, a sixth short circuit line is connected between the fifth microstrip line and the sixth microstrip line through a wire, and a seventh short circuit line is connected between the sixth microstrip line and the second coupling line through a wire; An input port is provided between the second microstrip line and the third microstrip line, a first output port is provided between the first microstrip line and the first coupling line, and a second output port is provided between the fourth microstrip line and the fifth microstrip line.

2. The Ka-band satellite communication phased array antenna feed network for enhancing transceiver isolation according to claim 1, wherein: The other ends of the first short circuit line, the second short circuit line, the third short circuit line, the fourth short circuit line, the fifth short circuit line, the sixth short circuit line, the seventh short circuit line, the first coupling line and the second coupling line are all connected to the ground.

3. The Ka-band satellite communication phased array antenna feed network for enhancing transceiver isolation according to claim 1, wherein: The line lengths and line widths of the first microstrip line, the second microstrip line, the third microstrip line, the fourth microstrip line, the fifth microstrip line and the sixth microstrip line are the same.

4. The Ka-band satellite communication phased array antenna feed network for enhancing transceiver isolation according to claim 1, characterized in that: The line lengths and line widths of the first coupling line and the second coupling line are the same.

5. The Ka-band satellite communication phased array antenna feed network for enhancing transceiver isolation according to claim 1, characterized in that: The line lengths of the first short circuit line, the second short circuit line, the third short circuit line, the fourth short circuit line, the fifth short circuit line, the sixth short circuit line and the seventh short circuit line are the same. The line widths of the second short circuit line, the third short circuit line, the fifth short circuit line and the sixth short circuit line are the same. The line widths of the first short circuit line and the seventh short circuit line are the same; the line widths of the first short circuit line, the second short circuit line and the fourth short circuit line increase in sequence.

6. The Ka-band satellite communication phased array antenna feeding network for enhancing transceiver isolation according to claim 1, characterized in that: The sixth microstrip line and the second coupling line are grounded through a load.

7. The Ka-band satellite communication phased array antenna feeding network for enhancing transceiver isolation according to claim 1, characterized in that: The feeding network is arranged on the substrate.

8. The Ka-band satellite communication phased array antenna feed network for enhancing transceiver isolation according to claim 7, characterized in that: The dielectric constant of the substrate is 4.3.

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