CMOS true-time delay IC for wideband phased-array antenna

Abstract

This paper presents a true-time delay (TTD) using a commercial 0.13-μm CMOS process for wideband phased-array antennas without the beam squint. The proposed TTD consists of four wideband distributed gain amplifiers (WDGAs), a 7-bit TTD circuit, and a 6-bit digital step attenuator (DSA) circuit. The T-type attenuator with a low-pass filter and the WDGAs are implemented for a low insertion loss error between the reference and time-delay states, and has a flat gain performance. The overall gain and return losses are >7 dB and >10 dB, respectively, at 2 GHz–18 GHz. The maximum time delay of 198 ps with a 1.56-ps step and the maximum attenuation of 31.5 dB with a 0.5-dB step are achieved at 2 GHz–18 GHz. The RMS time-delay and amplitude errors are <3 ps and <1 dB, respectively, at 2 GHz–18 GHz. An output P1 dB of