Embedded DiCAD linear phase shifter for 57–65GHz reconfigurable direct frequency modulation in 90nm CMOS

A digitally controlled artificial dielectric (DiCAD) differential transmission line is designed to perform agile linear phase shift over 100deg with thermometer-coded 16 step control. It also operates with a 16 gain-step VGA to enable re-configurable and direct-frequency modulation at 60 GHz with 256² states (1.1deg angular and 0.0007 magnitude resolutions) and -31 dB static EVM for multiple PSK/QAM modulations. The modulator uses 0.33 mm² core area in 90 nm CMOS and consumes 10 mA at 1 V.