With the advancement of CMOS technology, it has become possible to build compact and low cost sub-millimeter wave signal sources as local oscillator, and even to integrate entire transmitters and receivers on-chip. However, current signal source generation and transmission on CMOS technology suffer from poor performance in terms of output power and bandwidth due to the limited cut-off frequency fmax of the transistor.
In this talk, we propose ways of extending the operation frequency of CMOS around and above fmax on the range of sub-THz, and improving the performance of the signal sources and the down-converters. For that, a new topology of Colpitts VCO is introduced to answer simultaneously for the demand in high output power and wide tuning range. The harmonic approach is proposed to exploit higher harmonics of the fundamental Colpitts VCO topology to reach operation frequencies above the fmax. New design approaches and techniques are proposed and show state of the art performance.
For the signal generation, a model is developed for the Colpitts VCO to show analytically the amplitude behavior of the fundamental and the higher harmonics. While for the signal down-conversion, a model is developed to examine how the LO harmonics impact the conversion gain and NF of the down-converter operated above fmax.
To corroborate the theoretical analysis, the analytical models, the simulations and the circuit design, we show the design and the results of fabricated chips on different CMOS technologies. These chips validate the modeling, analysis and design we introduce, while demonstrating state of the art results in the 130-320 GHz range.