Multi-beam 4 GHz Microwave Apertures Using Current-Mode DFT Approximation on 65 nm CMOS
Abstract
A current-mode CMOS design is proposed for realizing receive mode multi-beams in the analog domain using a novel DFT approximation. High-bandwidth CMOS RF transistors are employed in low-voltage current mirrors to achieve bandwidths exceeding 4 GHz. Current mirrors realize the ADFT coefficients, which take simple values of 1, -1, 2, -2 only. An example using 1.2V current-mode approximate DFT on 65nm CMOS, with BSIM4 models from the RF kit, show up to 4 GHz with 8 independent aperture beams.