60 GHz Silicon-Based Tunable Amplifier

This paper presents, for the first time, 60 GHz silicon-based tunable amplifier development. A tunable transmission line is demonstrated to produce phase shift by using an on-chip multi-metal-layer structure with diode switch topology. A metal trace, below the transmission line, is connected to a pair of diode switches, to be grounded or left floating depending on whether the switch is on or off, respectively. A base-collector shorted npn HBT is used as diode switch, and a phase difference of 20 is measured in the two different states of the tunable transmission line over 35 GHz ~ 65 GHz frequency range. A tunable multi-band amplifier is developed by using this tunable transmission line in the output-matching network. Measured results of the amplifier indicate 3 dB bandwidth of operation can be achieved over the entire frequency range of 40 GHz to 65 GHz with a maximum gain of 8 dB by switching the diode on or off. This is the first demonstration of fully monolithic millimeter-wave tunable amplifiers on silicon-based IC processes.