A High-Speed V-Band Distributed OOK Modulator in 65 nm CMOS

This paper presents a high-speed V-band on-off keying (OOK) modulator in 65 nm CMOS based on distributed transmission lines architecture. The high-speed operation of the proposed OOK modulator is attained by distributing a single large switching transistor into smaller units. The effects of parasitic capacitances of each small switch are mitigated by series inductors, forming an artificial transmission line. The switch size and the number of stages are optimized for a reasonable balance between insertion loss and isolation. Small signal measurement of the OOK modulator reveals 3.8 dB insertion loss and 20.5 dB isolation at 60 GHz, with <5 dB insertion loss and >16 dB on-off ratio from 50 GHz to 70 GHz. Testing with a modulation setup shows the modulator is fully functional up to 5 Gbps at a 60 GHz carrier. Limitations of the test setup prevent modulation testing at >5 Gbps. The fabricated modulator does not consume any DC power and has an active footprint of 0.025 mm2.