290-GHz 17-dB ON-/OFF-Ratio Modulator With Resonance Control Varactors

A 17-dB on-/off-ratio modulator operating at 290 GHz that switches resonance frequencies of a transmission line resonator with two varactors is presented for ultrashort-distance communication. The resonance frequency is altered by the control voltage of the varactors. The high on/off ratio can be achieved due to a simple resonance control of a transmission line resonator. High-speed modulation is possible due to a small RC time constant associated with a control voltage node. It is fabricated by using a 65-nm CMOS process with a cutoff frequency of 220 GHz. We demonstrated an insertion loss of 3.49 dB, an on/off ratio of 17 dB, a bandwidth of 28 GHz, and data rates as high as 11.3 Gb/s.