Broadband lower-IF RF receiver based on microwave photonic mixer and Kramers-Kronig detection.

A broadband lower- intermediate-frequency (IF) radio frequency (RF) receiver with low cost and complexity based on a microwave photonic mixer and Kramers-Kronig (KK) detection is proposed and experimentally demonstrated. The feasibility of the proposed RF receiver is verified by comparing the error vector magnitude (EVM) performance of a down-converted IF signal with and without KK detection. EVM is measured as a function of IF carrier frequency, input local oscillator (LO) power, input RF power, and the coupling ratio between RF and LO paths. With KK detection, EVM can be improved by more than 9.5% when the IF carrier frequency is close to half of the signal bandwidth. This implies that a lower IF frequency can be down-converted with good EVM and that a low-speed photodetector and a low sampling rate analog to digital converter can be used for wideband RF signal reception.