Due to the electromagnetic interference produced by the high frequency switching on/off of power electronic devices

the detection technology under sinusoidal condition cannot be used for the detection of partial discharge（PD） under impulsive voltages with fast rise times. In this paper

a microstrip Balun is added to realize impedance matching and a dielectric layer with high permittivity is loaded on the radiation surface of the antenna to optimize the antenna structure. The gain of the antenna is improved in high frequency bandwidth of 0.5～1.5 GHz and the signal-to-noise ratio is enhanced distinctly. Then

we studied the time-frequency statistical characteristics of PD under different square pulse voltage parameters and antenna placement distance by using the UHF antenna designed for PD detection under voltage with fast rise time. Experimental results show that the amplitude of UHF signal in the frequency domain of 0.5～1.3 GHz decreases non-linearly with the increase of antenna placement distance. The influence of voltage frequency on the high frequency components of the discharge is remarkable

and the PD signal decays seriously with the increase of frequency. Through the simulation and experimental verification of the antenna

the optimal parameters are obtained. The thicknesses of the dielectric cover is 1 mm

and the distance from the radiation surface of the antenna is d = 30 mm. The gain is greater than 2.5 dB in the 500～900 MHz frequency band

greater than 7.0 dB in the 900 MHz～2 GHz frequency band

and the standing wave ratio is less than 1.4. The results obtained in this study can provide references and theoretical supports for PD detection of inverter-fed motor under high-frequency pulse voltage.