UHF Stacked Hilbert Antenna Array for Partial Discharge Detection

Abstract

This communication proposed an ultra-high frequency (UHF) stacked Hilbert antenna array to broaden bandwidth and increase gain of Hilbert fractal antenna. Two parasitic curves were added to improve the third order Hilbert curve and stacked structure was applied to the new antenna element. The UHF stacked Hilbert antenna was designed as antenna array that involved 2 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$\times$</tex></formula> 2 elements and fed by the Wilkinson's four-way power divider. Measurement results show that the UHF stacked Hilbert antenna array achieves a maximum gain of <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$-$</tex></formula> 1 dBi and exhibits a wide impedance bandwidth. Actual partial discharge (PD) experiments were carried out for typical artificial insulation defect models, while the proposed antenna array and an existing Hilbert fractal antenna were both used for PD measurements. The proposed antenna array was superior in this respect and effective for UHF online monitoring of PDs in electrical apparatus.