A dual-tone radar radio frequency front-end circuit

Abstract

The present invention discloses a dual-tone radar radio frequency front-end circuit, which is composed of a dual-polarized antenna, circulators I and II, signal sources I, II, and III, a quadrature coupler, mixers I and II. The horizontal polarization and vertical polarization ports of the dual-polarized antenna are respectively connected to ports 1 of circulators I and II. Ports 3 of circulators I and II are respectively connected to signal sources I and II. Ports 2 of circulators I and II are respectively connected to the input (P1) and isolation (P4) ports of the quadrature coupler. The through (P2) and coupled (P3) ports of the quadrature coupler are respectively connected to ports 1 of mixers I and II. Ports 3 of mixers I and II are connected to signal source III. Ports 2 of mixers I and II output differential intermediate frequencies IF+ and IF-, realizing a dual-tone radar radio frequency front-end circuit.

Description

Technical Field

[0001] The present invention relates to a dual-tone radar radio frequency front-end circuit. Background Art

[0002] Radar is moving from the military application field to daily life, such as detecting vital signs like breathing and heartbeat. Traditional radar radio frequency front-ends are increasingly difficult to meet the application requirements. Summary of the Invention

[0003] Based on the above problems, the present invention proposes a dual-tone radar radio frequency front-end circuit.

[0004] The present invention provides the following technical solutions:

[0005] The dual-tone radar radio frequency front-end circuit includes a dual-polarized antenna, circulators I and II, signal sources I, II, and III, quadrature couplers, mixers I and II. The horizontal and vertical polarization ports of the dual-polarized antenna are respectively connected to ports 1 of circulators I and II. Ports 3 of circulators I and II are respectively connected to signal sources I and II. Ports 2 of circulators I and II are respectively connected to the input (P1) and isolation (P4) ports of the quadrature coupler. The through (P2) and coupled (P3) ports of the quadrature coupler are respectively connected to ports 1 of mixers I and II. Ports 3 of mixers I and II are connected to signal source III. Ports 2 of mixers I and II output differential intermediate frequencies IF+ and IF-, thus realizing a dual-tone radar radio frequency front-end circuit.

[0006] The dual-tone radar radio frequency front-end circuit performs the following steps:

[0007] Step 1): Signal sources I and II output dual tones, exciting ports 3 of circulators I and II. After being transmitted through circulators I and II, they reach the horizontal and vertical polarization ports of the dual-polarized antenna, exciting the dual-polarized antenna to emit dual-tone electromagnetic waves. After being transmitted through free space to the target, the target reflects the dual-tone electromagnetic waves and transmits them back to the dual-polarized antenna through the same free space.

[0008] Step 2): The dual-polarized antenna receives the dual-tone electromagnetic waves reflected by the target and transmits them through the horizontal and vertical polarization ports of the dual-polarized antenna to ports 1 of circulators I and II. After being transmitted through circulators I and II, they reach the input (P1) port and isolation (P4) port of the quadrature coupler.

[0009] Step 3): According to the characteristics of the quadrature coupler, the dual-tone electromagnetic waves reflected by the target will be transmitted through the input (P1) and isolation (P4) ports to the through (P2) and coupled (P3) ports, that is, ports 1 of mixers I and II. Ports 3 of mixers I and II are connected to signal source III. The mixed output differential intermediate frequencies IF+ and IF- are obtained, thus realizing a dual-tone radar radio frequency front-end circuit. Description of the Drawings

[0010] Appendix Figure 1 It is a dual - tone radar radio frequency front - end circuit. Specific implementation mode

[0011] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0012] Embodiment

[0013] Appendix Figure 1 As shown in a dual - tone radar radio frequency front - end circuit, when the port 3 of circulator I is excited by acosω1t and the port 3 of circulator II is excited by acosω2t, after transmission through circulators I and II, the voltages of the horizontal (HP) and vertical (VP) polarization ports of the dual - polarization antenna can be expressed as

[0014] V HP = acosω1t (1)

[0015] V VP = acosω2t (2)

[0016] Assume that the round - trip transmission path loss between the dual - polarization antenna and the target is κ. Therefore, the dual - tone received by the dual - polarization antenna from the target reflection can be expressed as

[0017] V' HP = κacosω1t (3)

[0018] V' VP = κacosω2t (4)

[0019] Formulas (3, 4) are transmitted through circulators I and II to the input (P1) and isolation (P4) ports of the quadrature coupler. The S - parameters of the quadrature coupler are as follows.

[0020]

[0021] According to the characteristics of the quadrature coupler, formulas (3, 4) are redistributed and transmitted to the through (P2) and coupled (P3) ports of the quadrature coupler. Therefore, the voltages V DIR 、V COU can be calculated as

[0022]

[0023]

[0024] The voltages at the input port 1 of mixers I and II, that is, the voltages of formulas (6, 7). After mixing with the signal source III (frequency: ω IF =(ω1 + ω2) / 2) at port 3 of the mixer, the differential intermediate frequencies IF - and IF + are output at ports 2 of mixers I and II, and can be expressed as

[0025]

[0026]

[0027] In Formulas (8, 9), χ is the mixing coefficient of Mixers I and II. Mixers I and II output differential intermediate frequencies IF+ and IF- at Port 2, thereby implementing a dual-tone radar RF front-end circuit.

[0028] The dual-tone radar RF front-end circuit of the present invention is different from the single-tone excitation of traditional radars. Under the condition of dual-tone excitation, the output of differential intermediate-frequency signals can be achieved. The differential intermediate-frequency signals can be further amplified by a subsequent intermediate-frequency differential operational amplifier (not discussed in the present invention). At the same time, dual-tone excitation is performed in the vertical and horizontal polarization directions of the dual-polarized antenna to obtain more comprehensive target information in the dual-polarization directions, which can meet the comprehensive information acquisition requirements of radar applications (such as detecting vital signs such as breathing and heartbeat).

[0029] The above-described embodiments of the present invention are combinations of elements and features of the present invention. Unless otherwise mentioned, the elements or features may be considered optional. Each element or feature can be practiced without being combined with other elements or features. In addition, embodiments of the present invention can be constructed by combining some of the elements and / or features. The operation sequences described in the embodiments of the present invention can be rearranged. Some configurations of any embodiment can be included in another embodiment and can be replaced by the corresponding configuration of another embodiment. It is obvious to those skilled in the art that claims that do not have an explicit citation relationship with each other in the appended claims can be combined into embodiments of the present invention or can be included as new claims in the amendments after the present invention is filed.

[0030] In the form of firmware or software configuration, embodiments of the present invention can be implemented in the form of modules, processes, functions, etc. The software code can be stored in a memory unit and executed by a processor. The memory unit is located inside or outside the processor and can send data to the processor and receive data from the processor via various known means.

[0031] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual-tone radar radio frequency front-end circuit, characterized in that, It consists of a dual-polarized antenna, circulators I and II, signal sources I, II, and III, a quadrature coupler, and mixers I and II. The horizontal polarization and vertical polarization ports of the dual-polarized antenna are respectively connected to ports 1 of circulators I and II. Ports 3 of circulators I and II are respectively connected to signal sources I and II. Ports 2 of circulators I and II are respectively connected to the input (P1) and isolation (P4) ports of the quadrature coupler. The through (P2) and coupled (P3) ports of the quadrature coupler are respectively connected to ports 1 of mixers I and II. Ports 3 of mixers I and II are connected to signal source III, and ports 2 of mixers I and II output differential intermediate frequencies IF+ and IF-.

2. The dual-tone radar radio frequency front-end circuit according to claim 1, wherein The dual-tone radar RF front-end circuit performs the following steps: Step 1): Signal sources I and II output dual tones, which excite ports 3 of circulators I and II. After being transmitted through circulators I and II, they reach the horizontal polarization and vertical polarization ports of the dual-polarized antenna, exciting the dual-polarized antenna to emit dual-tone electromagnetic waves. The dual-tone electromagnetic waves are transmitted through free space to the target, and the target reflects the dual-tone electromagnetic waves and transmits them back to the dual-polarized antenna through the same free space. Step 2): The dual-polarized antenna receives the dual-tone electromagnetic waves reflected by the target, transmits them through the horizontal polarization and vertical polarization ports of the dual-polarized antenna to ports 1 of circulators I and II, and then transmits them through circulators I and II to the input (P1) port and isolation (P4) port of the quadrature coupler. Step 3): According to the characteristics of the quadrature coupler, the dual-tone electromagnetic waves reflected by the target will be transmitted from the input (P1) and isolation (P4) ports to the through (P2) and coupled (P3) ports, that is, ports 1 of mixers I and II. Ports 3 of mixers I and II are connected to signal source III, and the mixed output is differential intermediate frequencies IF+ and IF-, realizing a dual-tone radar RF front-end circuit.

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