Study on Flexible Built-in Miniature Archimedes Spiral Antenna Sensor for High-voltage electrical equipment PD Detection

Existing partial discharge (PD) ultra-high frequency (UHF) detection antennas are mostly based on rigid materials and require complex structural modifications to their flanges when built into high-voltage electrical equipment, which is not conducive to field applications. In this paper, a UHF Archimedes spiral antenna sensor based on a flexible thermosetting polyimide (TPI) substrate is designed and miniaturized in terms of antenna diameter. Simulations and measurements show that the designed flexible antenna has a diameter of 149 mm, which is 24.7% smaller than the non-miniaturised one. The VSWR of the flexible antenna is ⩽2 at bending radii of 0, 250, 300 and 350 mm in the 610 MHz to 3 GHz band, and the maximum Gain is 5.5 dB, with excellent radiation performance. The PD detection performance of the flexible antenna is measured and the results show that the designed flexible antenna can effectively detect the PD signal before and after the bending deformation.