Broadband Input Quasi-reflectionless BPF and BSF for 5G applications

Ultra-broadband single-port quasi-reflectionless (QR) filters with very wide 3-dB fractional bandwidth (FBW) of 120% in the passband for the QR bandpass filter (BPF) and stopband for the QR bandstop filter (BSF) are presented. The passband and stopband are realized using parallel coupled lines and parallel coupled lines with one end shorted, respectively. The absorptive filters are designed such that quasi-complementarity is satisfied by making the 3-dB FBW of the stopband and passband equal. Such QR filters in the diplexer configuration will be useful for 5G new radio frequency range 1 (Sub-6 GHz) applications.