Reconfigurable blocker-tolerant RF front-end filter with tunable notch for active cancellation of transmitter leakage in FDD receivers

A tunable N-path filter with an adaptive integrated notch is demonstrated for active cancellation of transmitter self-interference in frequency division duplexing (FDD) cellular systems. The proposed filter is a combination of N-path bandpass filter and N-path bandstop filter, with the center frequency of the bandstop filter is tuned to the transmitting frequency to suppress transmit leakage. The passband of the filter is tunable from 0.4 GHz to 1.4 GHz. The gain of the filter is 17 dB. The rejection of the filter is 74.5 dB, where the notch is created. The NF of the filter is from 3.8-4.7 dB over the whole tuning range. The total power consumption of the filter is 36.4-56 mW. The channel b ndwidth is 6.4 MHz and the out-of-band IIP3 is 21.2 dBm.