Attenuator with Small Phase Shift for Ultra-Wideband Pulse Subsurface Geo-Radar

The paper reports on the realization and measurements of the super-broadband hybrid-type current-controlled variable low phase shift attenuator for ultra-wideband pulse subsurface geo-radar. In the operational frequency band (0,1-2100 MHz) the attenuator has 30 dB attenuation and less than 4 degree phase shift, the VSWR is less than 2,2 at both input and output ports. The results demonstrate that the performance of the attenuator with correcting circuits is better than the transmission-type phase shift attenuator with the same measurement specifications.