An ultrare resolution biomimetic antenna array and transceiver assembly

Abstract

The application relates to the field of radar technology, and relates to a super-resolution bionic antenna array and a transceiving assembly.The antenna array comprises a plurality of antenna elements and a plurality of bionic coupling networks, one bionic coupling network is arranged between each two adjacent antenna elements, and the bionic coupling network is connected in series between the two antenna elements.The bionic coupling network is a differential amplifier, which is used for suppressing the voltage caused by common-mode excitation of the antenna elements and amplifying the voltage caused by differential-mode excitation of the antenna elements.The application can virtually increase the antenna aperture and improve the angle resolution, and the application occupies very little space and does not cause loss of output power.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radar, in particular to a super-resolution biomimetic antenna array and a transceiver assembly. BACKGROUND

[0002] The increasing demand for modern radar sensors is the ability to measure the angle of a target relative to the sensor axis. In particular, sensors that work in multi-target scenarios have a high requirement for angular resolution. This leads to antenna front-ends that usually have a large number of antenna elements and are large and heavy. However, if the available space or the number of realizable antenna elements is limited, alternative solutions must be found to achieve a high angular resolution.

[0003] A widely used method is the application of multiple-input multiple-output radar, in which a relatively large virtual aperture is formed by the spatial convolution of smaller transmit and receive apertures. Another possibility is the application of biomimetic antenna arrays. There is a parasitic fly in nature, the Ommaya brown fly, which, despite its very small acoustic aperture, can achieve an estimation accuracy of 1°-2° due to the special mechanical coupling between its ears. By adapting the concept from nature and imitating the dynamic properties of the hearing system of the Ommaya brown fly, biomimetic antenna arrays (BMAA) are designed to improve the angular resolution.

[0004] In recent years, with the growing demand for the application of active phased array radars and the development of microelectronic technology, the T / R transceiver assembly, as one of the key components of the active phased array radar, its cost accounts for about 70% of the entire radar, and its performance directly determines the key parameters such as the detection distance, resolution and sensitivity of the active phased array radar, and has an important influence on the size and weight of the active phased array radar. Therefore, the low-cost, miniaturized and high-reliability T / R transceiver assembly is the key to the active phased array radar. SUMMARY

[0005] In order to solve the problems existing in the prior art, the present application provides a super-resolution biomimetic antenna array which can increase the antenna aperture in a virtual manner, thereby improving the angular resolution, occupying very little space, and not causing loss of output power; the present application also provides a high-power T / R transceiver assembly which improves the radar power by increasing the power of the T / R transceiver assembly.

[0006] The super-resolution biomimetic antenna array of the present application comprises a plurality of antenna elements and a plurality of biomimetic coupling networks, one biomimetic coupling network is arranged between each adjacent two antenna elements, and the biomimetic coupling network is connected in series between the two antenna elements;

[0007] The bionic coupling network is a differential amplifier for suppressing the voltage caused by the common-mode excitation of the antenna elements and amplifying the voltage caused by the differential-mode excitation of the antenna elements.

[0008] Preferably, the two antenna elements in series with the bionic coupling network are respectively modeled by Norton equivalent current sources with short-circuit currents i1(ω, θ) and i2(ω, θ), where ω is the frequency and θ is the angle of incidence; the two antenna elements have the same self-inductance Y 11 , and the mutual inductance Y 12 between the two antenna elements is modeled by a voltage-controlled current source.

[0009] Preferably, the bionic coupling network comprises two symmetrical differential amplification circuits connected by a transformer with a voltage ratio of 1.

[0010] Further preferably, each differential amplification circuit of the bionic coupling network comprises a triode, and the common-mode amplification factor of the bionic coupling network is:

[0011]

[0012] where R b , R c , R e are the base resistance, the collector resistance and the emitter resistance of the triode in the bionic coupling network, r be is the emitter junction resistance of the triode in the bionic coupling network, R L is the load resistance, and β is the current amplification factor of the triode in the bionic coupling network.

[0013] Further preferably, each differential amplification circuit of the bionic coupling network comprises a triode, and the differential-mode amplification factor of the bionic coupling network is:

[0014]

[0015] where R b , R c are the base resistance and the collector resistance of the triode in the bionic coupling network, r be is the emitter junction resistance of the triode in the bionic coupling network, R L is the load resistance, and β is the current amplification factor of the triode in the bionic coupling network.

[0016] The application discloses a transceiving assembly of a super-resolution bionic antenna array, and the super-resolution bionic antenna array comprises a plurality of antenna elements and a plurality of bionic coupling networks, one bionic coupling network is arranged between each two adjacent antenna elements, and the bionic coupling network is connected in series between the two antenna elements; the bionic coupling network is a differential amplifier, which is used for suppressing voltage caused by common-mode excitation of the antenna elements and amplifying voltage caused by differential-mode excitation of the antenna elements.

[0017] The transceiving assembly is arranged on each antenna element of the super-resolution bionic antenna array and comprises a receiving channel, a transmitting channel, two transceiving switches, an attenuator and a phase shifter; the receiving channel and the transmitting channel are connected between the two transceiving switches, one transceiving switch is connected in parallel with the bionic coupling network, and the other transceiving switch is connected with the attenuator and the phase shifter in sequence.

[0018] An increasingly growing demand of modern radar sensors is to be able to measure the angle of a target relative to the sensor axis; compared with the prior art, the application can provide high angular resolution and realize working in a multi-target scene, and has the beneficial effects including:

[0019] 1. The application of the bionic antenna array of the application enables to improve the angular resolution without increasing the number of antenna elements and the size of the antenna.

[0020] 2. The bionic antenna array can be applied to any antenna array and is not limited to very small antenna spacing. The bionic antenna array takes two antenna elements as an example and can be extended to any even number of antenna elements.

[0021] 3. The application adopts the improved bionic coupling network, which can improve the angular resolution while ensuring no loss of output power and even increasing the output power. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is an electrical model diagram of the bionic antenna array in the embodiment of the application;

[0023] Figure 2 is an equivalent circuit diagram of the bionic antenna array in the embodiment of the application, wherein (a) is an equivalent circuit diagram of common-mode input, and (b) is an equivalent circuit diagram of differential-mode input;

[0024] Figure 3 is a vector diagram of a generalized BMAA model with a fixed incident angle, wherein (a) is a vector diagram without a bionic coupling network BMC, and (b) is a vector diagram with the bionic coupling network BMC;

[0025] Figure 4 is a structural schematic diagram of the bionic antenna array in the embodiment of the application, in which a plurality of antenna elements are connected in series with the bionic coupling network;

[0026] Figure 5 is a structural block diagram of a transceiver assembly in an embodiment of the present application. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be further described in detail below in combination with embodiments and drawings, but the embodiments of the present application are not limited thereto.

[0028] EMBODIMENT

[0029] The super-resolution biomimetic antenna array proposed in this embodiment has an electrical model as shown in Figure 1 , which includes a biomimetic coupling network (BMC), and a first antenna element, a first load resistor, a second antenna element and a second load resistor connected with the biomimetic coupling network respectively.

[0030] In this embodiment, the first antenna element and the second antenna element are respectively modeled by Norton equivalent current sources with short-circuit currents i1(ω,θ) and i2(ω,θ), where ω is frequency and θ is incident angle, which have the same self-impedance Y 11 . In addition, the mutual coupling between the two antenna elements is modeled by a voltage-controlled current source with mutual impedance Y 12 . The biomimetic coupling network includes a transformer with a voltage ratio of γ = 1, four triodes, a plurality of resistors, and four DC power supplies, and two symmetrical differential amplification circuits are formed by the four triodes and the plurality of resistors and the four DC power supplies; that is, the biomimetic coupling network includes two symmetrical differential amplification circuits connected by the transformer with a voltage ratio of 1, wherein each differential amplification circuit includes two triodes. The output of the antenna array system is given by the voltages u1(ω,θ) and u2(ω,θ) measured on the two load resistors R L .

[0031] Since there are two antenna elements, the system contains two input currents i1 and i2, and the circuit behavior can be completely described by the superposition of two linearly independent excitation modes, which are referred to as common-mode excitation (|i1| = |i2|, arg i1 = arg i2) and differential-mode excitation (|i1| = |i2|, arg i1 = -arg i2). The biomimetic coupling network acts as a kind of differential amplifier, which suppresses the voltage caused by the common-mode excitation of the antenna elements and amplifies the voltage caused by the differential-mode excitation of the antenna elements.

[0032] The working principle of the biomimetic antenna array of this embodiment is as follows:

[0033] Since the circuitry of the biomimetic antenna array is perfectly symmetrical, modal analysis is performed using the left-side circuit as an example. The voltage of the second antenna element is coupled to the left-side circuit via a transformer. The signals of the two antenna elements are i1(ω,θ) and i2(ω,θ), respectively, and their common-mode signal is... like Figure 2 As shown in Figure (a), the emitter resistance R of the transistor in the biomimetic coupling network e It has a negative feedback effect on common-mode signals, which can suppress the output voltage caused by common-mode signals. The common-mode amplification factor is:

[0034]

[0035] Among them, R b R c R e These represent the base resistance, collector resistance, and emitter resistance of the transistor in the biomimetic coupling network, respectively. be R is the emitter junction resistance of the transistor in the biomimetic coupling network. L β is the load resistance, and β is the current amplification factor of the transistor in the biomimetic coupling network.

[0036] The differential signal of the first antenna element is The differential signal of the second antenna element is Therefore, the differential input is (i1-i2), such as Figure 2 As shown in Figure (b), the emitter resistance R e There is no feedback effect for differential mode signals, and the differential mode amplification factor is:

[0037]

[0038] This embodiment uses Figure 3 The vector diagram in the image summarizes how this works.

[0039] Figure 3 Figure (a) shows the output signals u1 and u2 of a conventional uncoupled antenna array at an arbitrary but fixed incident angle θ = 0. u1 and u2 have the same amplitude and a phase difference φ. in It is equal to the phase difference between the excitation signals i1 and i2, that is:

[0040]

[0041] Where d is the spacing between antenna elements, k = 2π / λ is the free space wavenumber, and λ is the incident wave wavelength; for the sake of simplicity in subsequent formulas, an auxiliary quantity α is used. Where u c For common-mode voltage, u d This is the differential mode voltage.

[0042] Figure 3Figure (b) shows the results of applying the biomimetic coupled grid BMC in the same situation, the common-mode voltage u c of the output signal is significantly attenuated, while the differential-mode voltage u d and -u d are amplified. Thus, due to the biomimetic coupled grid BMC, the output signals u1 and u2 show a large phase difference φ out without reducing the signal amplitude.

[0043]

[0044]

[0045] wherein, is the input current after biomimetic coupling, is the differential-mode voltage and the common-mode voltage after biomimetic coupling; is the set auxiliary quantity after biomimetic coupling.

[0046] For each incident angle -90°≤ θ≤ 90°, for a biomimetic antenna array BMAA with an antenna spacing d≤ λ / 2, the absolute value of the output phase difference φ out is greater than or equal to the output phase difference φ in of a conventional array. For a fixed incident angle θ = θ0, this corresponds to a phase difference between the biomimetic coupled output ports that is greater than the phase difference that can be generated by the physical aperture.

[0047]

[0048] wherein, is the wave number after biomimetic coupling, is the antenna distance after biomimetic coupling. Since both the wave number k and the sine function value sin θ are not affected by the biomimetic coupling, i.e. the biomimetic output phase difference in equation (6) above is greater than the phase difference generated by the physical aperture, and can be converted into a biomimetic antenna distance that is greater than the physical antenna distance, i.e.

[0049] Two parameters are introduced to describe the performance of this biomimetic antenna array BMAA at the system level. The first parameter is the phase gain η, which relates the phase difference slope of a conventional antenna array and a BMAA with the same antenna elements and spacing, and is defined as:

[0050]

[0051] The second parameter is the normalized output level L out , which normalizes the power at the ports of the BMAA to the power measured at the ports of a conventional antenna array, i.e.

[0052]

[0053] where P out,BMAA is the output power of the port of the bionic antenna array, P out,regular is the output power of the port of the conventional antenna array.

[0054] If only the common-mode signal is attenuated and the differential-mode signal is kept unchanged, the output power will decrease while the phase difference increases, and the value of the normalized output level L out will be between 0 and 1. In the existing array antenna design, increasing the emitter resistance R e can suppress the common-mode, and increasing the current amplification factor β, the collector resistance R c , and the load resistance R L can amplify the common-mode signal and the differential-mode signal. Therefore, by modifying the circuit parameters, the phase gain η and the normalized output level L out can be adjusted to the actual required values, and the angular resolution is improved while the output power is not lost but even increased.

[0055] In the super-resolution bionic antenna array of the embodiment, the bionic coupling network is connected in series between two antenna elements, as shown in Figure 4 , a first bionic coupling network 5 is connected in series between a first antenna element 1 and a second antenna element 2, a second bionic coupling network 6 is connected in series between the second antenna element 2 and a third antenna element 3, and a third bionic coupling network 7 is connected in series between the third antenna element 3 and a fourth antenna element 4; by analogy, a bionic coupling network is arranged between each adjacent two antenna elements, and there are N-1 bionic coupling networks in the bionic antenna array containing N antenna elements.

[0056] A T / R transceiver assembly is connected to each antenna element of the active phased array radar antenna array, and the T / R transceiver assembly mainly includes a receiving channel, a transmitting channel, a transceiver switch, an attenuator, a phase shifter, and the like, and a principle block diagram thereof is shown in Figure 5 , the transceiver switch is provided with two, the receiving channel and the transmitting channel are connected between the two transceiver switches, one transceiver switch is connected in parallel with the bionic coupling network, and the other transceiver switch is connected with the attenuator and the phase shifter in sequence.

[0057] The first antenna element and the second antenna element receive signals u1 and u2 respectively; in the T / R transceiver assembly, the bionic coupling network is connected in parallel with the transceiver switch, so that the bionic coupling network is applied to the antenna array. As a kind of filter, the bionic coupling network is used to attenuate the common-mode voltage u c caused by common-mode excitation, and increase the differential-mode voltage u d caused by differential-mode excitation, so that the angular resolution of the T / R transceiver assembly is improved, and better performance is achieved.

[0058] When the transmitting signal comes, the transceiver switch is switched to transmitting, the transmitting signal passes through the phase shifter, the attenuator and the transceiver switch; then the transmitting signal is divided into two paths by the power divider after two-stage driving amplification, and then the two paths of power amplifiers respectively perform power amplification on the transmitting signal, and finally the two paths of transmitting signals are output after passing through the combiner, the transceiver switch and the bionic coupling network, so as to achieve a certain power design target.

[0059] According to the working sequence, the receiving channel is switched to receive the weak signal from the antenna, and the weak signal is output to the back end after passing through the bionic coupling network, the transceiver switch, the switch, the limiter, the low-noise amplifier, the transceiver switch, the attenuator and the phase shifter, so as to satisfy the receiving signal of A / D sampling, wherein the phase shifter and the attenuator are shared with the transmitting channel.

[0060] Although the embodiments of the present application have been shown and described above, it should be understood that the above-described embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and deformations to the above-described embodiments within the scope of the present application without departing from the principles and purposes of the present application.

Claims

1. An ultrare resolved bio-inspired antenna array, characterized by, The super-resolution bionic antenna array comprises a plurality of antenna elements and a plurality of bionic coupling networks, one bionic coupling network is arranged between each two adjacent antenna elements, and the bionic coupling network is connected in series between the two antenna elements. The bionic coupling network is a differential amplifier, which is used for suppressing the voltage caused by the common-mode excitation of the antenna element and amplifying the voltage caused by the differential-mode excitation of the antenna element. The bionic coupling network comprises two symmetrical differential amplification circuits connected through a transformer with a voltage ratio of 1. Each differential amplification circuit of the bionic coupling network comprises a triode, and the common-mode amplification multiple of the bionic coupling network is: wherein R b , R c , and R e are the base resistance, the collector resistance, and the emitter resistance of the transistor in the biomimetic coupling network, respectively, r be is the emitter junction resistance of the transistor in the biomimetic coupling network, R L is the load resistance, and β is the current amplification factor of the transistor in the biomimetic coupling network.

2. The super-resolution, bio-inspired antenna array of claim 1, wherein, The two antenna elements in series with the biomimetic coupled network are modeled by Norton equivalent current sources with short-circuit currents i1(ω, θ) and i2(ω, θ), where ω is the frequency and θ is the angle of incidence; the two antenna elements have the same self- admittance Y 11 The mutual coupling between the two antenna elements is modeled by a voltage-controlled current source with mutual admittance Y 12 .

3. The super-resolution, bio-inspired antenna array of claim 1, wherein, Each differential amplification circuit of the bionic coupling network comprises a triode, and the differential-mode amplification multiple of the bionic coupling network is: wherein R b , R c are the base resistance and the collector resistance of the transistor in the biomimetic coupling network, respectively, r be is the emitter junction resistance of the transistor in the biomimetic coupling network, R L is the load resistance, and β is the current amplification factor of the transistor in the biomimetic coupling network.

4. A transceiving assembly of a super-resolution biomimetic antenna array, characterized by, The super-resolution bionic antenna array comprises a plurality of antenna elements and a plurality of bionic coupling networks, one bionic coupling network is arranged between each two adjacent antenna elements, and the bionic coupling network is connected in series between the two antenna elements; the bionic coupling network is a differential amplifier, which is used for suppressing the voltage caused by the common-mode excitation of the antenna element and amplifying the voltage caused by the differential-mode excitation of the antenna element. The transceiving assembly is arranged on each antenna element of the super-resolution bionic antenna array and comprises a receiving channel, a transmitting channel, two transceiving switches, an attenuator and a phase shifter; the receiving channel and the transmitting channel are connected between the two transceiving switches, one transceiving switch is connected in parallel with the bionic coupling network, and the other transceiving switch is connected with the attenuator and the phase shifter in sequence. The bionic coupling network comprises two symmetrical differential amplification circuits connected through a transformer with a voltage ratio of 1. Each differential amplification circuit of the bionic coupling network comprises a triode, and the common-mode amplification multiple of the bionic coupling network is: wherein R b , R c , and R e are the base resistance, the collector resistance, and the emitter resistance of the transistor in the biomimetic coupling network, respectively, r be is the emitter junction resistance of the transistor in the biomimetic coupling network, R L is the load resistance, and β is the current amplification factor of the transistor in the biomimetic coupling network.

5. The transceiver assembly of claim 4, wherein, Each differential amplification circuit of the bionic coupling network comprises a triode, and the differential-mode amplification multiple of the bionic coupling network is: wherein R b , R c are the base resistance and the collector resistance of the transistor in the biomimetic coupling network, respectively, r be is the emitter junction resistance of the transistor in the biomimetic coupling network, R L is the load resistance, and β is the current amplification factor of the transistor in the biomimetic coupling network.

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