Inter-channel-gap-free four-channel microwave photonic channelizer with high image rejection for satellite networks

Future communication systems demand high-capacity broadband transmission and flexible multi-granularity resource allocation, making channelization a critical enabling technology. This work proposes a four-channel microwave photonic channelizer that removes inter-channel frequency gaps-overcoming spacing limits of 90° electrical hybrid in Hartley architectures-while ensuring high spectral utilization with a simple design. Experiments demonstrate an image rejection ratio (IRR) over 50 dB for single-tone RF signals from 15-23 GHz and successful down-conversion of four 2 GBaud QPSK signals to a common intermediate-frequency (IF) band, achieving error vector magnitude (EVM) below 14.30% and wideband isolation above 25 dB.