Design of microstrip bandpass filter used for PD UHF detecting in GIS

The ultra-high frequency antenna sensor is widely used for PD detecting in GIS. But the signal gained from antenna sensor is very weak and contains strong interference, and the energy loss of antenna sensor is not infinite out of the effective band, electromagnetic signal is coupled in antenna sensor at idling frequency band. So a micro-strip band-pass filter design method is introduced, and a band-pass filter and amplifier unit are designed based on micro-strip line theory. The high performance amplifier and the half-distributing parameter UHF filter whose work frequency band is 300/spl sim/1000 MHz and can cover with the frequency band of the antenna sensors. Testing results show that the performance of filter and amplifier is great and can be used to detect the feeble PD signals and suppress the low frequency interferes.