Experimental verification for time advancement of negative group delay in RF electronic circuits

An experiment was performed on the signal cancellation loop that utilises a carrier wave (CW) and wideband code division multiple access (WCDMA) signals to show that negative group delays can be used to cancel out positive group delays. According to the closed loop measurements, a 30 dB signal cancellation for a CW signal and a WCDMA 4FA signal were obtained over a 30 MHz bandwidth at the WCDMA downlink band, with a fabricated two-stage planar negative group delay circuit.