Miniature 1.87‐dB insertion‐loss V‐band CMOS bandpass filter with two enhanced finite transmission zeros

Abstract

In this article, we demonstrate a miniature low-insertionloss V-band bandpass filter with two finite transmission zeros by standard 0.13-lm CMOS technology. The proposed filter architecture has the following feature: the low-frequency transmission-zero and the high-frequency transmission-zero can be tuned by the series-feedback capacitor C s and the parallel-feedback capacitor C p , respectively. Parallel LC circuits (i.e., C 12 in parallel with L C1 -C 11 -L C2 and C 22 in parallel with L C3 -C 21 -L C4 ) are used for implementing C 1 and C 2 to improve the roll-off characteristic at high frequency and the depth of the upper notch. Besides, low-insertion-loss was achieved by adopting thick microstrip-line (MSL) with optimized ground-plane pattern as the needed inductors to minimize both the metal loss and the substrate loss. Over the frequency range of 49.5-82.5 GHz, the filter achieved insertion-loss (1/S 21 ) lower than 3 dB, and input return loss (S 11 ) and output return loss (S 22 ) better than À10 dB. The minimum insertion-loss was 1.87 dB at 66.5 GHz, a state-of-the-art result for a V-band CMOS bandpass filter. The chip area was only 0.466 Â 0.307 mm 2 , i.e., 0.143 mm 2 , excluding the test pads.