Controllable slow-wave delay line

On-chip transmission lines are basic components in millimeter-wave and terahertz circuits. In this paper, slow-wave CPW with a simple mosfet switch, ie. controllable slow-wave CPW as a controllable phase delay line are designed, characterized and analyzed in a commercial 0.18 μm CMOS process. Based on measured two-port S-parameters up to 110 GHz, the phase constants are compared at variation of the bias. It shows a continuously 15° delay over frequency range of 63 GHz to 98 GHz with a minimum insertion loss of 3.2 dB and a maximum insertion loss of 5.5 dB.