Eng · ·

Active Microwave Circuits

Active Microwave Circuits Active Microwave Circuits

Nonlinear characteristics of active devices, such as diodes and transistors, have been intensively investigated to improve the linearity and power performances of signal-amplifying and frequency-converting circuits. We have proposed distortion compensation using nonlinearities of a single diode in both forward-biased and reverse-based configurations and of anti-parallel reconfigurable transistor (ART) pairs. Noticeable linearity improvement offered by incorporating CMRCs in power amplifiers highlights the importance of out-of-band termination for the intermodulation response. A bias-adaptation technique dubbed self-adaptive biasing (SAB) is devised along with harmonic terminations as a novel circuit-level linearization technique for dynamic IMD sweet-spot control.

With strong technical knowledge and solid experience in the design of microwave circuits, our innovations have been subsequently validated by their use in industrial silicon-based CMOS and BiCMOS processes, as well as processes based on III-V compound semiconductors (such as GaAs). High-performance power amplifiers, mixers, and antenna switches have been successfully utilized for ISM band applications. We are currently working with nano-scale CMOS and multilayer post-processing in GaAs integrated circuits to explore our research on millimeter-wave and THz MMICs.