Performance Enhancement of a Sub-Sampling Circuit for Ultra-Wideband Signal Processing

An ultra-wideband (UWB) sampling mixer has been developed based on utilizing the combined advantages of two known circuit topologies: a wideband balun and a balanced-feed mixer. The developed sampler is integrated with a step-recovery diode strobe-step generator to sub-sample UWB signals. The fabricated sub-sampler demonstrated a 3.5-dB radio frequency to intermediate frequency (RF-IF) conversion loss up to 1 GHz (without the IF amplification), and a wide 3 dB bandwidth that exceeded 3.5-GHz. It has a reduced spurious level of better than -38 dBc, a lower sensitivity to the Schottky diode-placement, an excellent input match, and good isolation.