A 50-mW/ch 2.5-gb/s/ch data recovery circuit for the SFI-5 interface with digital eye-tracking

摘要

Typical frequency doublers achieve high conversion gain by reflecting back the 2nd harmonic to the input port of the active device through a quarter-wave open-circuited stub. In this paper, a S-band frequency doubler with a 12 dB conversion gain outperforms the conventional design by 5 dB, after replacing the conventional stub with a Compact Microstrip Resonant Cell (CMRC). The CMRC serves as suitable terminations for both the 2nd and 3rd harmonics to enhance the desired output power of the 2nd harmonic, while appearing as a good pass-band for the fundamental frequency.