Article Details

Abstract

To meet the miniaturization requirements of stepped-frequency ground-penetrating radar (SFGPR), the transmitting and receiving antennas of such radars are often positioned in a compact configuration, which inevitably induces strong interference signals due to direct electromagnetic coupling between the antennas. This paper presents a real-time adaptive Radio Frequency (RF) interference cancellation system based on a Field-Programmable Gate Array (FPGA) to suppress direct-wave interference and enhance echo detection capability in strong interference environments. The proposed system operates within a stepped-frequency signal regime with a frequency range of 200 MHz to 2 GHz and a bandwidth of 1.8 GHz. With an FPGA as the core controller, the system establishes a closed-loop link through key functional modules for signal adjustment and signal detection. With minimum interference signal power as the optimization objective, the FPGA dynamically and adaptively adjusts the phase and amplitude of the cancellation signal to achieve destructive interference, thereby realizing interference cancellation. Free-space experiments demonstrate that the system attains a cancellation ratio of 30 dB, significantly improving radar target detection performance.

Keywords

stepped-frequency ground-penetrating radar; RF interference cancellation; FPGA; adaptive adjustment

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About the authors

Liu Minye (1999.10-), male, Han ethnicity, from Danzhou, Hainan, is currently pursuing a master's degree in radio frequency interference cancellation.