A Novel Hilbert Antenna Enhanced With Metamaterials for Partial Discharge Detection

Partial discharge detection is critical for the maintenance and safety of high-voltage equipment. However, conventional UHF antennas suffer from limitations like excessive physical size and narrow bandwidth. This study proposes a novel Hilbert fractal curve-modified spiral antenna design to expand bandwidth without increasing the antenna’s physical dimensions. Furthermore, a symmetric open double-ring metamaterial structure is introduced to further improve the antenna’s performance. Fabricated as an 8×8 array and placed 10 mm above the Hilbert spiral antenna, this metamaterial structure significantly enhances the antenna’s gain, detection bandwidth, and directionality. Both simulation and experimental results demonstrate that the Hilbert spiral antenna integrated with the metamaterial achieves a voltage standing wave ratio (VSWR) < 2 over two wide frequency bands: 0.78–2.02 GHz and 2.22–3 GHz. This configuration delivers a 24.4% increase in operational bandwidth, a 4.61 dBi improvement in average gain, and enhanced directivity and radiation performance. This study used a partial discharge simulation platform to validate the antenna’s performance. Experimental results indicate that, at distances of 2-8 m, the metamaterial-integrated antenna exhibits 125% higher detection sensitivity than the antenna without metamaterials. Moreover, the detection range of antenna with metamaterials is expanded to 10 m.