Research on Multi-Band Interference Suppression Log Periodic Antennas for Partial Discharge Detection

he complex electromagnetic environment inside the substation can greatly affect the accurate detection of partial discharge (PD) signals, Band-reject frequency filters may be attached to the antenna, often at the detriment of the insertion loss. A novel log-periodic dipole array (LPDA) for ultra-high-frequency (UHF) PD detection in substations is proposed, featuring multi-band interference suppression capabilities. Based on a conventional LPDA model, an enhanced design covering 0.3-3 GHz is developed using ANSYS HFSS simulation software. The antenna is engineered to suppress interference from communication signals (0.79-0.96 GHz) and wireless transmission sources such as Wi-Fi and Bluetooth (2.4-2.5 GHz) through hardware-level optimization ， with the VSWR in these rejection bands exceeding 40. To address the issue of over-suppression commonly encountered in high-frequency narrowband interference mitigation, a dynamic scaling factor adjustment method is introduced. Furthermore, a multi-scaling-factor strategy is investigated to achieve frequency-specific gain control across multiple target bands，which elevates gain in the reconfigured band from 7 dBi to 9 dBi. A general design framework for developing LPDA with "multi-band, multi-gain, and interference-resilient" characteristics is proposed. Experimental validation is conducted with a focus on suppressing communication band interference, demonstrating 20 dB suppression against communication interference signals..