阅读说明：本技术 基于周期性相位调制的相控阵天线系统及其使用方法 (Phased array antenna system based on periodic phase modulation and application method thereof ) 是由 贺冲 易观理 于 2019-09-17 设计创作，主要内容包括：本发明提供了一种基于周期性相位调制的相控阵天线系统及其使用方法,包括：天线单元1和数字移相器件2,数字移相器件2与天线单元1一一相连,对天线单元1收发的射频信号的相位进行周期性的控制。本发明能利用简单的移相器件,实现对射频信号的相位的高精度调控。本发明尤其适用于低复杂度、低功耗、低成本的相控阵天线系统,可广泛应用于相控阵雷达、通信、导航和电子对抗等需要灵活波束控制的电子系统中。(The invention provides a phased array antenna system based on periodic phase modulation and a using method thereof, wherein the phased array antenna system comprises the following steps: the antenna unit 1 and the digital phase-shifting device 2, the digital phase-shifting device 2 and the antenna unit 1 are connected one by one, and the phase of the radio frequency signal received and transmitted by the antenna unit 1 is periodically controlled. The invention can utilize a simple phase-shifting device to realize high-precision regulation and control of the phase of the radio frequency signal. The invention is especially suitable for phased array antenna systems with low complexity, low power consumption and low cost, and can be widely applied to electronic systems which need flexible beam control, such as phased array radars, communication, navigation, electronic countermeasure, and the like.)

1. A phased array antenna system based on periodic phase modulation, comprising: the antenna comprises an antenna unit (1) and digital phase-shifting devices (2), wherein the digital phase-shifting devices (2) are connected with the antenna unit (1) one by one, and are used for periodically controlling the phase of a radio-frequency signal transmitted and received by the antenna unit (1).

2. Phased array antenna system based on periodic phase modulation according to claim 1, characterized in that the individual phase states of the digital phase shifting device (2) are between [0,2 pi ] and in an equal difference relationship.

3. Phased array antenna system based on periodic phase modulation according to claim 1, characterized in that it further comprises digital attenuators (3), the digital attenuators (3) being connected to the digital phase shifting devices (2) one by one for amplitude control of the radio frequency signals.

4. Phased array antenna system based on periodic phase modulation according to claim 3, characterized in that it further comprises a power divider (4) connected to all digital attenuators (3).

5. Phased array antenna system based on periodic phase modulation according to claim 4, characterized in that it further comprises a transceiving switch (5), a receiving branch and a transmitting branch, said receiving branch and said transmitting branch being connected to said power divider (4) through said transceiving switch (5).

6. The phased array antenna system based on periodic phase modulation according to claim 5, characterized in that the receiving branch comprises, connected in sequence: a down converter (6), a low-pass filter (7) and an analog-to-digital converter (8);

the down converter (6) is connected with the receiving and transmitting switch (5).

7. The phased array antenna system based on periodic phase modulation according to claim 5, characterized in that the transmitting branch comprises, connected in sequence: a digital-to-analog converter (10), an up-converter (11) and a low-pass filter (12);

the low-pass filter (12) is connected to the transmission/reception switch (5).

8. The phased array antenna system based on periodic phase modulation according to claim 5, characterized in that it further comprises an FPGA device (9), the FPGA device (9) is connected with the receiving branch, the transmitting branch and the digital phase shifting device (2);

the digital phase-shifting device (2) is controlled by an FPGA device (9).

9. Phased array antenna system based on periodic phase modulation according to claim 8, characterized in that the FPGA device (9) causes the amount of phase shift generated by the digital phase shifting device (2) to increase or decrease linearly within one phase modulation period and each phase state is of equal duration.

10. A method for using a phased array antenna system based on periodic phase modulation, characterized in that, the phased array antenna system based on periodic phase modulation as claimed in claim 1 is used to periodically control the phase of the radio frequency signal received and transmitted by the antenna unit (1), thereby indirectly controlling the phase of the generated first harmonic component and realizing the beam scanning at the first harmonic component.

Technical Field

The invention relates to the technical field of antenna engineering, in particular to a phased array antenna system based on periodic phase modulation and a using method thereof.

Background

The phased array antenna is widely applied to the technical fields of radar, electronic countermeasure, satellite communication, navigation and other engineering, and the basic principle is that the amplitude and the phase of each unit channel of the phased array are weighted, so that formed wave beams are changed in space in a short time. The traditional phase control device mostly adopts a digital phase shifter, and in order to realize high-precision beam pointing control, the digital phase shift device with 6 bits or more is often needed. However, the higher the number of bits of the digital phase shifter, the higher the insertion loss, the higher the cost, and the complexity of the control system. For example, a typical 6-bit X-band digital phase shifter has an insertion loss of 6.5dB (MAPS-010164 device by MA/COM corporation, usa) and 6 control lines. Because large active phased arrays often employ thousands of cells, the system loss, cost, and complexity caused by the use of conventional digital phase shifters is considerable. On the other hand, due to 5G mobile communication technology, especially millimeter wave communication in 5G often adopts phased arrays, and civil systems are more sensitive to cost and complexity. Therefore, there is a need to develop a phased array antenna technology of a new technology system.

The patent publication No. CN103916154B discloses a polarimetric transceiver front-end comprising: two receive channels configured to receive signals from the antenna, each receive channel corresponding to a respective polarization, each receive channel comprising a variable amplifier and a variable phase shifter; a first transmit path configured to transmit a signal to an antenna, the transmit path connected to a variable phase shifter of one of the two receive paths and including a variable amplifier; and a transmit/receive switch configured to select between the first transmit channel and the two receive channels for signals, the transmit/receive switch comprising a quarter-wave transmission line that adds a high impedance to the transmit channel when the transmit/receive switch is in a receive state.

Disclosure of Invention

In view of the defects in the prior art, the present invention provides a phased array antenna system based on periodic phase modulation and a method for using the same.

According to the invention, the phased array antenna system based on the periodic phase modulation comprises: the antenna unit 1 and the digital phase-shifting device 2, the digital phase-shifting device 2 and the antenna unit 1 are connected one by one, and the phase of the radio frequency signal received and transmitted by the antenna unit 1 is periodically controlled.

Preferably, the respective phase states of the digital phase shifting device 2 are between [0,2 π ] and in an arithmetic relationship.

Preferably, the digital phase-shifting device also comprises digital attenuators 3, wherein the digital attenuators 3 are connected with the digital phase-shifting devices 2 in a one-to-one mode and are used for carrying out amplitude control on the radio frequency signals.

Preferably, a power divider 4 is also included, connected to all digital attenuators 3.

Preferably, the power divider further comprises a transceiving switch 5, a receiving branch and a transmitting branch, wherein the receiving branch and the transmitting branch are connected with the power divider 4 through the transceiving switch 5.

Preferably, the receiving branch comprises, connected in sequence: a down-converter 6, a low-pass filter 7 and an analog-to-digital converter 8;

the down-converter 6 is connected to the transmit-receive switch 5.

Preferably, the transmitting branch comprises, connected in sequence: a digital-to-analog converter 10, an up-converter 11 and a low-pass filter 12;

the low-pass filter 12 is connected to the transmit/receive switch 5.

Preferably, the device further comprises an FPGA device 9, and the FPGA device 9 is connected with the receiving branch, the transmitting branch and the digital phase shift device 2;

the digital phase shift device 2 is controlled by the FPGA device 9.

Preferably, the FPGA device 9 linearly increases or decreases the amount of phase shift produced by the digital phase shifting device 2 during one phase modulation cycle, with each phase state being of equal duration.

According to the application method of the phased array antenna system based on the periodic phase modulation, the phased array antenna system based on the periodic phase modulation is adopted to periodically control the phase of a radio frequency signal transmitted and received by the antenna unit 1, so that the phase of the generated first harmonic component is indirectly controlled, and the beam scanning at the first harmonic component is realized.

Compared with the prior art, the invention has the following beneficial effects:

the digital phase shift devices with low bit positions are subjected to periodic phase modulation, and the phase of signals is indirectly controlled by controlling the modulation time sequence of the digital phase shift devices on each unit channel, so that beam scanning is realized. Also, the accuracy of this phase control method is reconfigurable, which is related to the dominant frequency of the control signal and the bandwidth of the signal. The invention can realize high-precision phase shift control under the condition of narrower bandwidth of the transmitted signal.

The phase shift precision which can be realized only by a traditional high bit number (for example, a 6-bit phase shifter which has 64 phase states and is subjected to phase control by 6 control lines) is realized by using a digital phase shift device with a small number of phase shift states (for example, 3-6 phase states and is subjected to phase control by 2-3 control lines). Therefore, the invention can reduce the hardware complexity of the phased array system, is beneficial to reducing the volume, the cost and the like of the phased array system, and simultaneously improves the reliability.

The invention is especially suitable for phased array antenna systems with low complexity, low power consumption and low cost, and can be widely applied to electronic systems which need flexible beam control, such as phased array radars, communication, navigation, electronic countermeasure, and the like.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of phase increment periodic modulation in a phase state;

FIG. 3 is a schematic diagram of phase decreasing periodic modulation in the phase state;

FIG. 4 is a schematic diagram of the control timing of the digital phase shifting device on the reference cell and the delay of the control timing of the digital phase shifting device on the nth cell relative to the reference control timing;

FIG. 5 is a normalized power spectrum of a signal modulated with an increasing phase period in three phase states according to the first embodiment;

FIG. 6 is a normalized power spectrum of a signal modulated with decreasing phase periods in three phase states according to the first embodiment;

FIG. 7 is a normalized power spectrum of a signal modulated with an increasing phase period in four phase states according to the first embodiment;

FIG. 8 is a normalized power spectrum of a signal modulated with an increasing phase period in five phase states according to the first embodiment;

fig. 9 is a schematic diagram illustrating a comparison between a normalized directional diagram and an ideal directional diagram formed by the present invention in the second embodiment.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

As shown in fig. 1, the present invention provides a phased array antenna system based on periodic phase modulation, including: the antenna comprises an antenna unit 1, a digital phase-shifting device 2, a digital attenuator 3, a power divider 4, a transceiving switch 5, a receiving branch, a transmitting branch and an FPGA device 9.

The digital phase shifters 2 are connected to the antenna units 1 one by one, and periodically control phases of radio frequency signals received and transmitted by the antenna units 1. The respective phase states of the digital phase shift device 2 are between 0,2 pi and in an arithmetic relationship. The digital attenuators 3 are connected with the digital phase shift devices 2 one by one, and carry out amplitude control on the radio frequency signals. The power divider 4 is connected to all the digital attenuators 3. The receiving branch and the transmitting branch are connected with the power divider 4 through the transceiving switch 5.

The receiving branch comprises the following components connected in sequence: a down-converter 6, a low-pass filter 7 and an analog-to-digital converter 8; the down-converter 6 is connected to the transmit-receive switch 5. The emission branch comprises the following components connected in sequence: a digital-to-analog converter 10, an up-converter 11 and a low-pass filter 12; the low-pass filter 12 is connected to the transmit/receive switch 5. The FPGA device 9 is connected with the receiving branch, the transmitting branch and the digital phase-shifting device 2; the digital phase shift device 2 is controlled by the FPGA device 9. The FPGA device 9 linearly increases or decreases the amount of phase shift produced by the digital phase shifting device 2 during one phase modulation cycle, and each phase state is of equal duration.

For the receiving state, the transceiving switch 5 is switched to the receiving branch, and the antenna unit receives the electromagnetic wave radiated by the space. The digital phase shift devices on each unit channel perform periodic phase modulation on signals received by the antenna units. Referring to fig. 1, the digital phase shift device has M phase shift states, each phase shift state adopts microstrip lines with different lengths and is selectively implemented by a single-pole multiple access switch, and the phase shift amounts of the phase shift states of the digital phase shift devices are respectively:

m is the mth digital phase shifter, M belongs to M, and the phase shift state of the digital phase shifter is periodically controlled through the FPGA device 9. In a modulation period T_pAnd the phase shift state of the phase-shifting plate is uniformly and linearly changed. Referring to FIGS. 2 and 3, the amount of phase shift increases from 0 to 2 π (M-1)/M or decreases from 2 π (M-1)/M to 0 during a modulation cycle, and each phase stateThe duration is the same. For example, if M ═ 4, in one modulation period T_pIn, at [0, T_p/4) setting the phase shift of the digital phase shifter to 0 in the time period; in [ T ]_p/4,T_pIn the time period of/2), setting the phase shift of the digital phase shifter to be pi/2; in [ T ]_p/2,3T_pIn the time period of/4), setting the phase shift of the digital phase shifter to be pi; in [3T ]_p/4,T_p) During the time period, the phase shift of the digital phase shifter is set to 3 pi/2.

Assuming that the signal entering the digital phase shifter is at carrier frequency F_cAfter periodic phase modulation, for the modulation state with increasing phase, the main energy of the signal will be concentrated to F_c+F_pWherein F is_pTo correspond to the modulation period T_pThe modulation frequency of (2). And the energy of the signal will be allocated to the carrier frequency F_c+(Mk+1)F_pOn other harmonic components. Due to the fact thatIf the bandwidth of the transmitted signal is B, in order to avoid aliasing of the energy of the signal, the following relation should be satisfied:

B＜MF_p (2)

accordingly, for a modulation state with decreasing phase, the dominant frequency of its signal will be centered at F_c-F_pThe energy of the signal will also be allocated to a carrier frequency of F_c+(Mk-1)F_pOn other harmonic components.

It should be noted that although the digital phase shifter with microstrip lines and single-pole multiple access rf switch structure shown in the drawings is used for illustration in the description of the present invention, the present invention is not limited to the structure of the digital phase shifter, and the digital phase shifter implemented by using other principles can also meet the technical requirements of the present invention. In addition, the conventional digital phase shifter adopts 2^pA phase shift state, where p is the number of bits of the digital phase shifter. In the present invention, the phase shifter state M is not limited, and for example, M is 3,5,6, etc., and the present invention can be applied as long as the phase shift state of the formula (1) is satisfied.

The beam pattern synthesis according to the present invention is as follows, and phase modulation with increasing phase will be described here as an example.

The goal of the hypothetical pattern synthesis is to direct the beam to theta₀And the beam sidelobe is less than SLL. The phased array is an N-unit one-dimensional uniform array, and the array element spacing is D. Firstly, calculating the amplitude weight on each unit channel by adopting Chebyshev weighting, and normalizing the amplitude weight. And modulating the state of the digital attenuator 3 on each unit channel to enable the attenuation quantity to be equal to the amplitude weight value. For the phase weight, an equiphase plane synthesis method is adopted to obtain the phase required on each unit channel as follows:

φ_n＝-(n-1)KDsinθ₀ (3)

wherein K is the carrier frequency F_c+F_pThe wave number of (c). Setting the first unit as reference unit, using FPGA controller to make phase shift amount change from 0 to 2 pi (M-1)/M period, and the duration of each phase shift amount is T_pand/M. Referring to FIG. 4, for the nth cell, the timing of the control of the phase shift state is compared to the reference stateSame, but with a specific time delay τ_n. Controlling delay tau by FPGA_nThe phase shift amount of the nth unit channel relative to the reference unit channel (corresponding to the carrier frequency F)_c+F_pThe positive first harmonic component) of which the mathematical relationship is:

thus, if the relationship is satisfied:

ρ_n＝φ_n,n＝2,3,...,N (5)

i.e. by controlling the time delay tau_nTo indirectly control the generated positive first harmonic (carrier frequency F)_c+F_pIn) phase, beam pattern pointing theta that achieves the positive first harmonic₀. The time delay tau on each unit channel is obtained by the formula (5)_nComprises the following steps:

therefore, the invention realizes amplitude and phase weighting by controlling the modulation timing sequence of the digital attenuator and the digital phase shifter, thereby realizing beam scanning. From the formula (4), the delay τ_nThe minimum step of (a) determines the minimum step of the phase shift produced by such periodic modulation. And τ_nIs controlled by an FPGA device, the minimum step of which is usually equal to the clock period T of the system_clk. Therefore, under the phase modulation method of the present invention, the minimum step of the phase shift amount generated by the method is:

as can be seen from equation (7), by changing the clock period T of the system_clkThe minimum step size of the phase shift can be reconstructedT_clkThe smaller the step accuracy. It is to be understood that the present invention can provide high precisionThe basic principle of phase shift control of degrees.

For the transmitting state, the digital attenuator is also adopted to realize amplitude weighting and phase weighting on the digital phase shift device, so that beam scanning is realized. The principle and process are similar to those of the receiving state, and therefore, the description is not repeated. In addition, the amplitude and phase weighting method provided by the present invention is not limited to the chebyshev weighting (amplitude weighting) and equiphase plane synthesis (phase weighting) methods, and other beam pattern synthesis methods can be realized by the hardware and method architecture provided by the present invention.