Circularly polarized antenna with multi-stage RC-CR cascade circuit

Abstract

The utility model provides a circularly polarized antenna with a multi-stage RC-CR cascade circuit, and the antenna comprises the multi-stage RC-CR cascade circuit which is used for broadening the bandwidth of the circularly polarized antenna, receives an input signal, and outputs a first feed signal, a second feed signal, a third feed signal, and a fourth feed signal, wherein the amplitudes of the first feed signal, the second feed signal, the third feed signal and the fourth feed signal are equal, the phase differences are 90 degrees in sequence, and the multi-stage RC-CR cascade circuit is formed by cascading a plurality of single-stage RC-CR circuits.

Description

Technical Field

[0001] The present application relates to the field of antennas, and more specifically, to circularly polarized antennas. Background Art

[0002] The conventional feeding network is composed of a cascade of a power divider, a 90° bridge or a phase shifter based on a microstrip line, and the bandwidth of such a feeding network is narrow. To solve the above problem, the present invention designs a circularly polarized antenna with a multi-stage RC-CR cascade circuit. Summary of the invention

[0003] The present application provides a circularly polarized antenna with a multi-stage RC-CR cascade circuit, comprising: a multi-stage RC-CR cascade circuit, for widening the bandwidth of the circularly polarized antenna, which receives an input signal and outputs a first feed signal, a second feed signal, a third feed signal and a fourth feed signal, wherein the amplitudes of the first feed signal, the second feed signal, the third feed signal and the fourth feed signal are equal, and the phases differ by 90 degrees respectively, and the multi-stage RC-CR cascade circuit is a cascade of multiple single-stage RC-CR circuits, the single-stage RC-CR circuit includes four resistors and four capacitors, the frequency of the input signal is 1 / 2πRC, R is the impedance value of the resistor, and C is the capacitive reactance value of the capacitor; a radio frequency switch, which respectively selects the first feed signal, the second feed signal, the third feed signal and the fourth feed signal, and And send them to the power amplifier respectively, the power amplifier sends the output signal to the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit respectively through the radio frequency switch, and radiates the circularly polarized signal to the space through the excitation of the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit; each of the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit is provided with a feeding point, the feeding points of the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit respectively receive the spatial signal, the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit send the output signal of the radio frequency switch to the low noise amplifier respectively, and the low noise amplifier sends the output signal to the multi-stage RC-CR cascade circuit.

[0004] The above antenna can widen the frequency band and be used in a wider frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] In order to better describe and illustrate the embodiments of the present application, reference may be made to one or more drawings, but the additional details or examples used to describe the drawings should not be considered as limiting the scope of the invention of the present application, any of the currently described embodiments or preferred methods.

[0006] Figure 1 It is a schematic diagram of a multi-element circularly polarized antenna.

[0007] Figure 2 It is a schematic diagram of a multi-feed circularly polarized antenna.

[0008] Figure 3 It is a schematic diagram of the radiation unit of a multi-element circularly polarized antenna.

[0009] Figure 4 It is a schematic diagram of the radiation unit of a multi-feed point circularly polarized antenna.

[0010] Figure 5 It is the circuit diagram of a single-stage RC feeding network.

[0011] Figure 6 It is the circuit diagram of multi-stage RC-CR feeding network.

[0012] Figure 7 is the schematic diagram of the feeding network.

[0013] Figure 8 is the schematic diagram of the feeding network.

[0014] Fig. 9 is the schematic diagram of the feeding network.

[0015] Fig.10 is the schematic diagram of the feeding network.

[0016] Fig.11 is the schematic diagram of the feeding network. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0018] Combine the following Figure 1-6 A circularly polarized antenna with a multi-stage RC-CR cascade circuit is introduced. When the angle between the polarization plane of the radio wave and the normal plane of the earth changes periodically from 0 to 360°, that is, the electric field magnitude remains unchanged, the direction changes with time, and the trajectory of the end of the electric field vector is projected as a circle on a plane perpendicular to the propagation direction, it is called circular polarization. The circularly polarized antenna can be set with four feeding points (i.e., signal input ports) and four radiating units. The circularly polarized antenna generates four groups of signals with equal amplitudes and phases of 0°, 90°, 180°, and 270° respectively through the feeding network. The feeding network includes an RC network, which is an analog circuit that obtains the desired frequency response by adjusting the values ​​of capacitors and resistors. Among them, the single-stage RC-CR feeding network consists of 4 groups of resistors and 4 groups of capacitors.

[0019] An RF switch is a switching device used to control RF signals. Its function is to realize the switching function of the signal in the RF circuit, and can transmit or block the RF signal. RF switches are usually composed of one or more pairs of switch elements, which can change the path of the signal under different conditions. LNA refers to a low noise amplifier, which is an amplifier with a very low noise coefficient. It is generally used as a high-frequency or intermediate-frequency preamplifier for various radio receivers, and an amplification circuit for highly sensitive electronic detection equipment. In the case of amplifying weak signals, the noise of the amplifier itself may seriously interfere with the signal, so it is hoped to reduce this noise to improve the output signal-to-noise ratio. PA refers to a power amplifier, which amplifies weak electrical signals from a signal source or a preamplifier. Differential transmission is a signal transmission technology. Different from the traditional practice of one signal line and one ground line, differential transmission transmits signals on both lines. The two signals have the same amplitude and opposite phase. The signal transmitted on these two lines is a differential signal.

[0020] In one embodiment, a circularly polarized antenna with a multi-stage RC-CR cascade circuit is provided, comprising: a multi-stage RC-CR cascade circuit for widening the bandwidth of the circularly polarized antenna, which receives an input signal and outputs a first feed signal, a second feed signal, a third feed signal and a fourth feed signal, wherein the amplitudes of the first feed signal, the second feed signal, the third feed signal and the fourth feed signal are equal, and the phases are successively different by 90 degrees, and the multi-stage RC-CR cascade circuit is a cascade of multiple single-stage RC-CR circuits, the single-stage RC-CR circuit includes four resistors and four capacitors, the frequency of the input signal is 1 / 2πRC, R is the impedance value of the resistor, and C is the capacitive reactance value of the capacitor; a radio frequency switch, which respectively selects the first feed signal, the second feed signal, the third feed signal and the fourth feed signal , and send them to the power amplifier respectively, the power amplifier sends the output signal to the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit respectively through the RF switch, and radiates the circularly polarized signal to the space through the excitation of the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit; each of the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit is provided with a feeding point, and the feeding points of the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit respectively receive the space signal, and the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit send the output signal of the RF switch to the low noise amplifier respectively, and the low noise amplifier sends the output signal to the multi-stage RC-CR cascade circuit.

[0021] In another embodiment, a circularly polarized antenna with a multi-stage RC-CR cascade circuit is provided, including: a multi-stage RC-CR cascade circuit for widening the bandwidth of the circularly polarized antenna, which receives an input signal and outputs a first feed signal, a second feed signal, a third feed signal and a fourth feed signal, wherein the amplitudes of the first feed signal, the second feed signal, the third feed signal and the fourth feed signal are equal, and the phases are successively different by 90 degrees, and the multi-stage RC-CR cascade circuit is a cascade of multiple single-stage RC-CR circuits, the single-stage RC-CR circuit includes four resistors and four capacitors, the frequency of the input signal is 1 / 2πRC, R is the impedance value of the resistor, and C is the capacitive reactance value of the capacitor; a radio frequency switch selects the first feeding signal, the second feeding signal, the third feeding signal and the fourth feeding signal, respectively, and sends them to the power amplifier, and the power amplifier sends the output signal to the first feeding point, the second feeding point, the third feeding point and the fourth feeding point of the radiating unit through the radio frequency switch; the radiating unit receives the spatial signal, and the first feeding point, the second feeding point, the third feeding point and the fourth feeding point of the radiating unit are sent to the low noise amplifier through the signal output by the selection of the radio frequency switch, and the low noise amplifier sends the output signal to the multi-stage RC-CR cascade circuit respectively.

[0022] In another embodiment, the circularly polarized antenna with a multi-stage RC-CR cascade circuit further includes an input module that outputs a differential signal; or the input module includes a balun circuit, and the input of the balun circuit is a single-ended input signal.

[0023] Combine the following Figure 7-11 Introduce the principle of the feed network. According to the sequence theory (basis function), for any phasor set of 4 input signals, it can be decomposed into 4 types of sequence superposition: orthogonal clockwise (C phasor), orthogonal counterclockwise (A phasor), collinear differential (B phasor), collinear same direction (D phasor), such as Figure 7 As shown in the figure, the collinear differential and collinear unidirectional components generate common-mode components at the output. When the system uses a differential circuit, the common-mode component can be suppressed, so only the orthogonal clockwise and orthogonal counterclockwise components need to be considered.

[0024] How to build an RC network Figure 8 As shown. When the input signal frequency is 1 / (2πRC), it moves to -45 degrees and +45 degrees respectively when passing through the resistor and capacitor. When the order of the 4 input signals is orthogonal counterclockwise (left side of the figure below), the phasor of each output node is superimposed by two adjacent orthogonal input phasors after passing through -45 degrees and 45 degrees respectively, and the phases are consistent, so the phasor doubles; at the same time, the 4 outputs are still orthogonal signals; and for the 4 input signals are orthogonal clockwise (right side of the figure below), because the phases after superposition are inconsistent and are 180 degrees, that is, in the opposite direction, the energy will be eliminated, that is, the orthogonal clockwise cannot pass through this RC network.

[0025] like Fig. 9 As shown, according to the above principle, the differential signal can be decomposed into 4 orthogonal counterclockwise and 4 orthogonal clockwise signals, which generate 4 orthogonal signals after passing through the above RC network. Fig.10 As shown in FIG. 1 , when it is desired to operate in a wider frequency band, multiple RC-CR networks can be added, wherein each RC-CR network has a different frequency point. Fig.11 As shown in Figure 1, image rejection is usually used to evaluate the orthogonal performance of the 4-way orthogonal phase. Cascading multiple RC networks can achieve better 4-way orthogonal performance over a wider frequency band.

[0026] The advantage of the present application over the prior art is that the present invention designs a new type of feeding network, using a passive RC-CR circuit as a four-phase generator for a circularly polarized antenna, which can generate equal-amplitude orthogonal four-phase signals. Compared with the traditional microstrip line power divider, phase shifter or bridge combination to realize the four-phase signal, the size of the feeding network solution is greatly reduced. For example, if discrete R and C components are used on a PCB board, the size is much smaller than the traditional solution. In addition, the solution of the present application has a wide bandwidth: the multi-stage RC-CR cascade network technology can achieve an octave bandwidth (as shown in the simulation, more than 4 times the octave can be achieved). In addition, the solution of the present application has a wide range of uses. A set of passive RC-CR four-phase generating circuits can be applied to antennas of different frequency bands (can be used simultaneously in L, S, C, X and other frequency bands). In addition, the solution of the present application has a strong driving capability: the RC-CR cascade network is combined with an active circuit, the signal link loss is small, and the driving capability is strong.

[0027] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0028] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A circularly polarized antenna with a multi-stage RC-CR cascade circuit, comprising: A multi-stage RC-CR cascade circuit, for widening the bandwidth of a circularly polarized antenna, receiving an input signal and outputting a first feed signal, a second feed signal, a third feed signal and a fourth feed signal, wherein the amplitudes of the first feed signal, the second feed signal, the third feed signal and the fourth feed signal are equal, and the phases differ by 90 degrees respectively, and the multi-stage RC-CR cascade circuit is a cascade of multiple single-stage RC-CR circuits, the single-stage RC-CR circuit includes four resistors and four capacitors, the frequency of the input signal is 1 / 2πRC, R is the impedance value of the resistor, and C is the capacitive reactance value of the capacitor; A radio frequency switch, which respectively selects the first feed signal, the second feed signal, the third feed signal and the fourth feed signal, and sends them to the power amplifier respectively. The power amplifier sends the output signal to the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit respectively through the radio frequency switch, and radiates the circularly polarized signal into space through the excitation of the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit; Each of the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit is provided with a feeding point, and the feeding points of the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit respectively receive spatial signals, and the first radiation unit, the second radiation unit, the third radiation unit and the fourth radiation unit respectively send the signals output by the selection of the RF switch to the low noise amplifier, and the low noise amplifier sends the output signal to the multi-stage RC-CR cascade circuit.

2. A circularly polarized antenna with a multi-stage RC-CR cascade circuit, comprising: A multi-stage RC-CR cascade circuit, used for widening the bandwidth of a circularly polarized antenna, receiving an input signal and outputting a first feed signal, a second feed signal, a third feed signal and a fourth feed signal, wherein the amplitudes of the first feed signal, the second feed signal, the third feed signal and the fourth feed signal are equal, and the phases differ by 90 degrees respectively, and the multi-stage RC-CR cascade circuit is a cascade of multiple single-stage RC-CR circuits, the single-stage RC-CR circuit includes four resistors and four capacitors, the frequency of the input signal is 1 / 2πRC, R is the impedance value of the resistor, and C is the capacitive reactance value of the capacitor; A radio frequency switch, which respectively selects the first feed signal, the second feed signal, the third feed signal and the fourth feed signal, and sends them to the power amplifier respectively, and the power amplifier sends the output signal to the first feed point, the second feed point, the third feed point and the fourth feed point of the radiation unit respectively through the radio frequency switch; The radiation unit receives the spatial signal, and the first feeding point, the second feeding point, the third feeding point and the fourth feeding point of the radiation unit send the signal output by the RF switch to the low noise amplifier, and the low noise amplifier sends the output signal to the multi-stage RC-CR cascade circuit respectively.

3. The circularly polarized antenna with a multi-stage RC-CR cascade circuit according to claim 1 or 2, characterized in that It also includes an input module that outputs a differential signal; or the input module includes a balun circuit, and the input of the balun circuit is a single-ended input signal.

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