Fast phase flip antenna unit based on radio frequency switch

Abstract

The invention discloses a fast phase flip antenna unit based on a radio frequency switch. The fast phase flip antenna unit comprises a PCB dielectric substrate, a printed dipole antenna, a reflective single-pole double-throw radio frequency switch chip, a symmetric feed balun, a radio frequency input microstrip line and a radio frequency output microstrip line, the radio frequency input microstrip line and the radio frequency output microstrip line input radio frequency signals into the radio frequency switch chip and output radio frequency signals out of the radio frequency switch chip, the two ends of the symmetrical feed balun are connected with the radio frequency switch chip respectively to achieve impedance matching, and the radio frequency signals are received or transmitted between the middle of the symmetrical feed balun and the printed dipole antenna; the left end and the right end of the symmetrical feed balun are respectively in a radio frequency signal input state and an open circuit state by switching a control signal of the switch chip, so that the current directions in the symmetrical feed balun are completely opposite, and the transmitted or received radio frequency signal is overturned by 180 degrees. According to the invention, the phase control function of the radio-frequency signal can be realized with an extremely simple and reliable structure, the cost of a phased array system is greatly reduced, and the reliability of the system is improved.

Description

Technical Field

[0001] The invention belongs to the field of radio frequency microwaves, and in particular relates to a fast phase flip antenna unit based on a radio frequency switch. Background Art

[0002] Traditional mechanical scanning antennas have large inertia and slow speed, but phased array antennas overcome this shortcoming and have a high beam scanning speed. Phased array antennas change the shape of the pattern by controlling the feeding phase of the radiating elements in the array antenna to achieve the purpose of beam scanning. Its feeding phase is generally controlled by an electronic computer, and the phase changes quickly, that is, the maximum direction of the antenna pattern changes rapidly.

[0003] The key components of traditional phased array antennas are phase shifters and antenna radiating elements. Phase shifters should ensure that the required phase shift value is obtained within a certain frequency range, and also need to meet certain requirements such as power resistance and temperature stability to ensure that the phased array antenna can work normally at different frequencies and under changing environmental conditions. The design of the antenna radiating element should minimize the change in input impedance within a certain phase shift range and a certain frequency range to ensure the normal operation of the transmitter.

[0004] The feeding methods of phased array antennas are divided into transmission line feeding and space feeding. In the transmission line feeding method, the RF energy is fed to the radiating unit through microwave transmission lines such as waveguides, coaxial lines and microstrip lines, and the phase shifter is placed in the microwave transmission line. Although phased array antennas have made great progress compared to mechanical antennas, their high circuit complexity and high cost have always restricted the further promotion and development of phased array antennas. Summary of the invention

[0005] The purpose of the present invention is to provide a fast phase flip antenna unit based on a radio frequency switch, which can realize the phase control function of the radio frequency signal with an extremely simple and reliable structure, greatly reduce the cost of the phased array system, and improve the system reliability.

[0006] One aspect of the present invention provides a fast phase flip antenna unit based on a radio frequency switch, comprising a PCB dielectric substrate, a printed dipole antenna, a reflective single-pole double-throw radio frequency switch chip, a symmetrical feeding balun, and radio frequency input and output microstrip lines; The printed dipole antenna is located on the back side of the PCB dielectric substrate, the reflective single-pole double-throw radio frequency switch chip, the symmetrical feeding balun, and the radio frequency input and output microstrip lines are located on the front side of the PCB dielectric substrate, and the printed dipole antenna, the reflective single-pole double-throw radio frequency switch chip, the symmetrical feeding balun, and the radio frequency input and output microstrip lines are all completely axisymmetric structures; The RF input and output microstrip lines are used to input RF signals into the reflective single-pole double-throw RF switch chip or output RF signals from the reflective single-pole double-throw RF switch chip. The symmetrical feeding balun is a clamp-type symmetrical structure. The left and right ends of the symmetrical feeding balun are respectively connected to the reflective single-pole double-throw RF switch chip to achieve impedance matching with the reflective single-pole double-throw RF switch chip. The middle part of the symmetrical feeding balun is used to transmit RF signals to the printed dipole antenna or receive RF signals from the printed dipole antenna. By switching the control signal of the reflective single-pole double-throw RF switch chip, the left and right ends of the symmetrical feeding balun can be respectively in a state of passing the RF signal and an open circuit state, so that the current direction in the symmetrical feeding balun is completely opposite, thereby achieving a 180° flip of the RF signal transmitted or received by the antenna unit.

[0007] Preferably, when the switch control signal is at a high level, the RF signal is passed from the reflective single-pole double-throw RF switch chip into the left end of the symmetrical feed balun, and the right end of the symmetrical feed balun is in an open circuit state; when the switch control signal is at a low level, the RF signal is passed from the reflective single-pole double-throw RF switch chip into the right end of the symmetrical feed balun, and the left end of the symmetrical feed balun is in an open circuit state.

[0008] Preferably, the left and right ends of the symmetrical feeding balun are respectively connected to the reflective single-pole double-throw RF switch chip through gradient lines, and impedance matching with the reflective single-pole double-throw RF switch chip is achieved through the gradient lines.

[0009] The fast phase flip antenna unit based on the RF switch according to the above aspect of the present invention can realize the phase control function of the RF signal with an extremely simple and reliable structure, greatly reduce the cost of the phased array system, and improve the system reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work: Figure 1 It is a structural schematic diagram of a fast phase flip antenna unit based on a radio frequency switch according to an embodiment of the present invention; Figure 2 It is a schematic diagram of the structure of a symmetrical feeding balun according to an embodiment of the present invention. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] An embodiment of the present invention provides a fast phase flip antenna unit based on a radio frequency switch. Figure 1 1 is a schematic diagram of a structure of a fast phase flip antenna unit based on a radio frequency switch according to an embodiment of the present invention, wherein (a) is a front view, (b) is a back view, and (c) is a side view. Figure 1 As shown, the fast phase flip antenna unit based on the radio frequency switch of the embodiment of the present invention includes: a PCB dielectric substrate 1, a bottom printed dipole antenna 2, a reflective single-pole double-throw radio frequency switch chip 3, a symmetrical feeding balun 4, and radio frequency input and output microstrip lines 5.

[0013] The PCB dielectric substrate 1 is a single-layer PCB dielectric substrate 1, the printed dipole antenna 2 is located on the back of the PCB dielectric substrate 1, and the reflective single-pole double-throw RF switch chip 3, the symmetrical feeding balun 4, and the RF input and output microstrip line 5 are located on the front of the PCB dielectric substrate 1. The printed dipole antenna 2, the reflective single-pole double-throw RF switch chip 3, the symmetrical feeding balun 4, and the RF input and output microstrip line 5 are all designed with a completely axisymmetric structure, and the entire antenna unit layout is also completely axisymmetric, which can ensure that when the switch channel is switched, the phase shift degree can be accurately guaranteed to be 180°. The symmetrical feeding balun 4 is a clamp-type symmetrical structure design, such as Figure 2 As shown, the middle part is the antenna feeding part 41, which is used to realize the antenna feeding function, and the two ends are the impedance matching parts 42, which are used to realize the impedance matching function. The ends of the two ends are connected to the reflective single-pole double-throw RF switch chip 3 through a gradient line. The gradient line can transform the impedance to 50 ohms, thereby realizing impedance matching with the reflective single-pole double-throw RF switch chip 3. The middle bending part of the symmetrical feeding balun 4 can feed the RF energy into the bottom printed dipole antenna 2, thereby transmitting the RF signal to the printed dipole antenna 2 and radiating the RF signal into space.

[0014] When the antenna unit transmits a radio frequency signal, the radio frequency signal is input into the reflective single-pole double-throw radio frequency switch chip 3 through the radio frequency input and output microstrip lines 5, the reflective single-pole double-throw radio frequency switch chip 3 is powered and the switch control signal is set to a high level, the reflective single-pole double-throw radio frequency switch chip 3 outputs the radio frequency signal from its RF1 pin, thereby passing into the left end of the symmetrical feeding balun 4, and the RF2 pin of the reflective single-pole double-throw radio frequency switch chip 3 is in an open-circuit state, so that the right end of the symmetrical feeding balun 4 is also in an open-circuit state; the two ends of the symmetrical feeding balun 4 are each impedance matched with the radio frequency switch chip 3 through a gradient line, and the radio frequency energy is fed into the bottom printed dipole antenna 2 in the middle to radiate the radio frequency signal into space.

[0015] The control signal of switching the reflective single-pole double-throw RF switch chip 3 is low level, and the reflective single-pole double-throw RF switch chip 3 outputs the RF signal from its RF2 pin, thereby passing it into the right end of the symmetrical feed balun 4, and the RF1 pin of the reflective single-pole double-throw RF switch chip 3 is in an open circuit state, so that the left end of the symmetrical feed balun 4 is also in an open circuit state. The current direction of the symmetrical feed balun 4 is exactly opposite in the two states of the reflective single-pole double-throw RF switch chip 3, thereby realizing a 180° flip of the RF signal transmitted by the antenna unit.

[0016] Similarly, when the antenna unit is in the receiving state, when the printed dipole antenna 2 receives a radio frequency signal from space, the state of the reflective single-pole double-throw radio frequency switch chip 3 is switched by a switch control signal, so that the phase of the received radio frequency signal can be flipped by 180°.

[0017] Compared with the prior art, the fast phase flip antenna unit based on the RF switch of the embodiment of the present invention has the following significant advantages: (1) The phase control function of the RF signal is realized with an extremely simple and reliable structure, which greatly reduces the cost of the phased array system and improves the system reliability; (2) Due to the high-speed switching characteristics of the RF switch, the phase switching time of the antenna unit of the embodiment of the present invention can be less than 10ns; (3) Compared with the traditional phased array antenna unit using phase shifters with limited working bandwidth and low phase shifting accuracy, the antenna unit of the embodiment of the present invention can achieve high-precision phase flipping in the entire frequency band due to the design of the symmetrical feeding balun; (4) Due to the integrated design of the antenna and the RF circuit and the reduction of RF interfaces, the antenna unit of the embodiment of the present invention achieves extremely low insertion loss and improves the efficiency of the system.

[0018] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A fast phase flip antenna unit based on a radio frequency switch, characterized in that: It includes PCB dielectric substrate, printed dipole antenna, reflective single-pole double-throw RF switch chip, symmetrical feed balun, RF input and output microstrip lines; The printed dipole antenna is located on the back side of the PCB dielectric substrate, the reflective single-pole double-throw radio frequency switch chip, the symmetrical feeding balun, and the radio frequency input and output microstrip lines are located on the front side of the PCB dielectric substrate, and the printed dipole antenna, the reflective single-pole double-throw radio frequency switch chip, the symmetrical feeding balun, and the radio frequency input and output microstrip lines are all completely axisymmetric structures; The RF input and output microstrip lines are used to input RF signals into the reflective single-pole double-throw RF switch chip or output RF signals from the reflective single-pole double-throw RF switch chip. The symmetrical feeding balun is a clamp-type symmetrical structure. The left and right ends of the symmetrical feeding balun are respectively connected to the reflective single-pole double-throw RF switch chip to achieve impedance matching with the reflective single-pole double-throw RF switch chip. The middle part of the symmetrical feeding balun is used to transmit RF signals to the printed dipole antenna or receive RF signals from the printed dipole antenna. By switching the control signal of the reflective single-pole double-throw RF switch chip, the left and right ends of the symmetrical feeding balun can be respectively in a state of passing the RF signal and an open circuit state, so that the current direction in the symmetrical feeding balun is completely opposite, thereby achieving a 180° flip of the RF signal transmitted or received by the antenna unit.

2. The antenna unit according to claim 1, characterized in that When the switch control signal is at a high level, the RF signal passes from the reflective single-pole double-throw RF switch chip into the left end of the symmetrical feed balun, and the right end of the symmetrical feed balun is in an open circuit state; when the switch control signal is at a low level, the RF signal passes from the reflective single-pole double-throw RF switch chip into the right end of the symmetrical feed balun, and the left end of the symmetrical feed balun is in an open circuit state.

3. The antenna unit according to claim 1 or 2, characterized in that: The left and right ends of the symmetrical feeding balun are respectively connected to the reflective single-pole double-throw radio frequency switch chip through gradient lines, and impedance matching with the reflective single-pole double-throw radio frequency switch chip is achieved through the gradient lines.

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