A microstrip line-fed wideband printed antenna is presented for radio detection of partial discharge (PD). The novel simple structure antenna has compact size of 24 $\times $ 20 $\times $ 0.16 cm$^{3}$ (0.28$\lambda_{s} \times $ 0.23 $\lambda_{s} \times $ 0.002 $\lambda_{s})$ and is suitable for radiometric PD wireless sensor nodes, where $\lambda_{s}$ is the wavelength of the lowest frequency of the band (i.e. 0.35 GHz). A stepped and beveled radiation patch is used in combination with a slotted ground plane to achieve a wide fractional bandwidth of 119% (0.35 to 1.38 GHz) for a return loss better than 10 dB. Good radiation pattern characteristics are obtained across the frequency band of interest. The match between simulated and experimental results suggests that the design is sound and robust.