CN110109082A - A kind of Terahertz Active Radar imaging array of shared antenna - Google Patents

Abstract

The invention discloses a common-antenna terahertz active radar imaging array, which includes an antenna array arranged on one side of a local oscillator and capable of working in receiving and/or transmitting modes, by controlling the shared antennas of the array elements constituting the antenna array The bias voltage of the transmitting link or the receiving link thus realizes switching between the receiving mode, the transmitting mode and the transmitting-receiving working mode that completes the transceiver function, so that the antenna array can be used as a transmitting array, a receiving array and a transmitting and receiving array respectively. mode to use. The invention reduces the number of antenna arrays used, improves the utilization rate of the chip area and reduces the processing cost under the premise of not changing the imaging scale and not affecting the normal operation of the transmitting link and the receiving link.

Description

A Terahertz Active Radar Imaging Array with Common Antenna

technical field

The present invention relates to the technical field of terahertz imaging, in particular to a terahertz active radar imaging array with a common antenna, and in particular to a structure of a shared antenna for the transmitting and receiving links of the terahertz radar imaging array.

Background technique

Terahertz wave is an electromagnetic wave between microwave and infrared light on the electromagnetic spectrum, its frequency is about 0.1-10THz, and its wavelength corresponds to 3mm-30μm. Terahertz technology is one of the frontier and hot areas of information science and technology research. In recent years, it has received extensive attention from research institutions around the world. Due to the high frequency of terahertz, it has a high signal-to-noise ratio in the time-domain spectrum, and different objects absorb terahertz frequencies differently, resulting in different spectral characteristics. Therefore, terahertz technology is increasingly used in the field of imaging to achieve high-precision detection of objects.

In the design of the terahertz imaging system, considering the relatively large scale of the imaging array, in order to meet the needs of low cost and application, the advantages of terahertz transceiver chips based on semiconductor technology in future product applications are becoming more and more obvious. In the process of realizing the terahertz imaging system based on the semiconductor process, due to the characteristics of the process and the characteristics of the terahertz frequency, many problems are faced in the design process, such as: skin effect, interconnection, parasitic parameters, large transmission loss, etc. Therefore, it is very difficult to design a terahertz chip based on semiconductor technology. The design process needs to be verified step by step, and the performance of each link can be correctly evaluated during the test process. Quickly locate problematic modules. At the same time, in order to meet the needs of practical applications, the imaging chip requires multiple transceiver modules to form an array to jointly complete the imaging task. In the process of realizing the traditional Time Division Duplexing (TDD) terahertz imaging array, there are severe transceiver coupling and limited isolation, and only one transmitting antenna array and receiving antenna array are working at the same time. However, this will greatly increase the cost of tape-out processing and the risk of design due to the presence of a large amount of chip area at the same time as the transceiver antenna array.

To sum up, in order to solve the problems existing in the traditional TDD terahertz imaging array and reduce the area of the same array, it is necessary to propose a new terahertz radar imaging architecture to improve the utilization rate of the imaging array chip area and be able to New imaging array architectures that reduce processing costs.

Contents of the invention

The object of the present invention is to provide a common-antenna terahertz active radar imaging array for the technical defects existing in the prior art.

The technical scheme adopted for realizing the purpose of the present invention is:

A terahertz active radar imaging array with a common antenna, including an antenna array that can work in the receiving and/or transmitting mode on one side of the local oscillator, by controlling the transmitting link of the shared antenna of the array elements constituting the antenna array Or the bias voltage of the receiving link so as to realize the switching between the receiving mode, the transmitting mode and the transmitting-receiving working mode that completes the transceiver function, so that the antenna array can be used as a transmitting array, a receiving array and a transmitting and receiving array in three modes. to use.

The antenna array includes a plurality of array elements capable of working in receiving and/or transmitting modes, the plurality of array elements are connected, and the antenna of each array element is a reconfigurable antenna, and the reconfigurable The antenna is respectively connected to the receiving circuit and the transmitting circuit; the receiving circuit and the transmitting circuit are respectively connected to a bias circuit which controls the switching state of the transmitting link or the receiving link.

Between the two adjacent oscillators of the local oscillator, phase shifters are respectively introduced in the horizontal and vertical directions to realize differential control to change the phases of the upper row and column of the array respectively, and to adjust the phase and phase of the local oscillator. Frequency, so as to realize the phase synchronization and extraction of local oscillators at different positions in the array, and complete the active imaging of the entire terahertz array.

The active radar imaging architecture of the terahertz transceiver shared antenna array proposed by the present invention effectively optimizes the transceiver array in the traditional TDD imaging chip without changing the imaging scale, and adopts an antenna array through the idea of sharing the transceiver antenna array It can meet the requirements of both the transmitting array link and the receiving array link.

Wherein, the antennas of the array elements in the antenna array are reconfigurable antennas, and switching between different modes is realized by combining the reconfigurable antennas and controlling the bias voltage of the transmitting link or receiving link.

By sharing an antenna array through the transceiver array link, without changing the size of the array, this greatly improves the utilization rate of the chip area and reduces the processing cost, the chip area is reduced by 40%, and the cost is also reduced by 40%;

At the same time, it can also work as any one of the three modes of transmitter, receiver or transceiver through bias voltage control, which greatly increases the practicability of the chip and meets the needs of various application scenarios.

In addition, the present invention is based on semiconductor technology, which is convenient for integration with back-end circuits, easy to realize mass production, and further reduces the cost of subsequent product development.

Description of drawings

Figure 1-2 is a schematic diagram of the traditional TDD radar transceiver array and array elements;

3-4 are structural schematic diagrams of the terahertz common antenna active radar imaging array and array elements of the present invention;

5a-5c are schematic diagrams of implementations of sending and receiving of array elements of the imaging array of the present invention;

FIG. 6 is a schematic diagram of synchronizing a control array oscillator proposed by the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

In order to illustrate the technical solution of the present invention more clearly, the present invention will be further described by taking an array size of 4×4 as an example below in conjunction with the accompanying drawings.

Figure 1-2 shows the traditional TDD terahertz radar imaging structure, the transmitting antenna array is 100 on the left of the local oscillator 300, and the receiving antenna array is 200 on the right of the local oscillator. Among them, the array element 10 of the transmitting antenna array 100 is composed of a transmitting antenna 1 and a transmitting (Transmitter, referred to as "Tx") circuit, and the receiving antenna array 200 is composed of a receiving antenna and a receiving (Receiver, referred to as "Rx") circuit. constitute. Two antenna arrays exist at the same time, occupying a large amount of chip area. The processing cost is increased, and the complexity of the design is also increased.

The common-antenna terahertz active radar imaging array provided by the present invention is implemented and designed based on semiconductor technology. Improvements are made to those shown in Figure 1-2, and the antennas of the transmitting link and the receiving link are shared. As shown in Figure 3-4, an antenna array 110 is set on the entire chip, a local oscillator 310 is on one side, and the antenna array 110 It can be used in three modes: transmitting array, receiving array and sending and receiving array respectively.

Wherein, the array element 11 in the antenna array 110 is connected by a transceiver link 12, and the array element 11 includes a receiving antenna 3 and a transceiver (Transceiver, referred to as "TRx") circuit 4 connected to the transmitting and receiving antenna, and the TRx circuit includes a Tx circuit 41 and the Rx circuit 42, they together form the element 11 of an antenna array 110. The composition of the elements 11 of each antenna array 110 is shown in Figures 5a-5c. The bias circuit A provides bias for the normal operation of the Tx circuit, and the bias circuit B provides bias for the normal operation of the Rx circuit. Figure 5a shows the array element structure based on reconfigured antennas.

In the present invention, the setting of the working state of the entire chip is realized by controlling the state of the bias circuit of the transmitting link or receiving link of the array element. When the bias circuits A and B are in the on and off states respectively, the chip is in the transmitting mode, as shown in Figure 5b; when the bias circuits A and B are in the off and on states, respectively, the chip is in the receiving mode, as shown in Figure 5c Shown; when the switching state of bias circuit A and bias circuit B is quickly switched at a specific frequency, the chip can quickly switch between the transmitting and receiving modes to complete the entire transceiver function.

In Figure 6, in order to ensure the normal operation of the array, a phase shifter (PhaseShifter, referred to as "PS") is introduced between two adjacent oscillators to adjust the phase and frequency of the oscillator to achieve different positions in the array. phase synchronization of the oscillators. The specific synchronization principle will be described below in conjunction with the two-dimensional Adler equation. As shown in formula 1.

In formula (1), ω ₀ represents the initial frequency of the oscillator, k is a constant, Represents the phase difference between two adjacent oscillators in the same column (row), ψ _col (ψ _row ) represents the phase change produced by the phase shifter between two adjacent oscillators in each column (row), ω represents the oscillator final angular frequency.

From formula (1) we know that the phase and frequency of each element in the array are related to the adjacent elements. If all coupling phases (ψ _row and ψ _co l) on the row and column are changed equally, the locked frequency of the oscillator will change, but the phase constant. For example, when the phases of all couplings are increased by the same amount, the frequency of the oscillator will be reduced to keep the phase difference of the oscillators constant. On the other hand, if the coupled phase shifters between the oscillators are changed differentially (±ψ _row /±ψ _col ), the relative phases of adjacent oscillators will change but the frequency will not change.

Therefore, by introducing phase shifters in the horizontal and vertical directions to achieve differential control to change the phases of the upper row and column of the array, the phase synchronization and extraction of the entire array oscillator can be realized, and the active imaging of the entire terahertz array can be completed.

Considering the area and processing cost brought by the array scale of the imaging system, the present invention innovatively proposes to use one antenna array to meet the requirements of transmission and reception at the same time, without changing the imaging scale and without affecting the normal operation of the transmission link and the reception link. Under the premise of the work, the number of antenna arrays used can be reduced, the utilization rate of the chip area can be improved and the processing cost can be reduced, and the design of the terahertz active radar imaging array can be realized.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, these improvements and Retouching should also be regarded as the protection scope of the present invention.

Claims (3)

1. a kind of Terahertz Active Radar imaging array of shared antenna, which is characterized in that including being located at local oscillator side Can receive and or emission mode under the aerial array that works, the common antenna of the array element of aerial array is made up of control Emit the bias voltage of link or receives link to realize in reception pattern, emission mode and the hair for completing transmission-receiving function The switching of operating mode is penetrated-received, can be used as emission array, receiving array and transmitting-receiving array to make the aerial array respectively Three models come carry out using.

2. the Terahertz Active Radar imaging array of shared antenna as described in claim 1, which is characterized in that the aerial array packet Include it is multiple can receive and or emission mode under the array element that works, be connected between multiple array elements, the day of each array element Line is reconfigurable antenna, and the reconfigurable antenna, which is separately connected, receives circuit and transmit circuit；The reception circuit and transmitting electricity Road is separately connected the biasing circuit of control transmitting link or receives link switch state.

3. the Terahertz Active Radar imaging array of shared antenna as described in claim 1, which is characterized in that the local oscillator Adjacent two oscillator between, introduce phase shifter respectively in the horizontal and vertical directions, realize that difference control changes respectively The change in formation arranges the phase of upper row and column, for adjusting the phase and frequency of local oscillator, to realize in array at different location The Phase synchronization and extraction of local oscillator complete the Active Imaging of entire Terahertz array.