A 60 GHz adaptive antenna array in CMOS

Very high data-rate wireless communications is becoming a reality with the opening of the 60GHz band, and the increasing speed and integration of analog circuitry in CMOS. The short wavelength at 60GHz causes a high path loss between antennas which makes directive antennas necessary. The channel between antennas also changes either due to the transmitter or receiver being mobile or to other changes in the physical environment around the transmitter and receiver. The only directive antenna that can adapt to these changes is an adaptive beamforming array. The performance of analog circuits in CMOS at such high frequency is barely adequate but the short wavelength allows for circuit styles not usually attempted in CMOS.;The work presented here focuses on the design and implementation of a phased array analog front-end chip and the antennas themselves. The key circuit block is a RF phase shifter operating at the 60GHz carrier frequency which is replicated to build the array to simplify the system. A thorough understanding of the operation of phase shifting antenna arrays is developed to gain insight into the design of these crucial circuits. This understanding is used to greatly simplify the design of the phase shifters and increase their robustness to uncertainties in the channel, in the packaging and antennas and in the CMOS processing.;A 4-way antenna array is designed and implemented in 0.13mum CMOS. From the beginning, the system design is highly modular which allows prediciton of the antenna array pattern accuracy from basic simulations or measurements. There is only one unique active circuit block, an RF phase selector, which is replicated to build a phase shifter. On-chip measurements of the active circuits show that very good antenna array patterns are possible.