A Continuously Adjustable True Time Delay for D-Band Timed Antenna Arrays

This paper presents a fully integrated true time delay (TTD) circuit for beamforming applications based on the delay sum principle operating at a center frequency of 144 GHz with a 3 dB bandwidth of 26 GHz. It features a measured delay range of 1.75 ps whose resolution is only limited by the integrated digital-to-analog converter (DAC). A demonstrator has been manufactured in a 130 nm bipolar complementary metal-oxide-semiconductor (BiCMOS) technology, occupying 0.53 × 0.3mm
²
of chip area including serial peripheral interface (SPI), bandgap reference and four DACs.