A MIXED-SIGNAL ROW/COLUMN ARCHITECTURE FOR VERY LARGE MONOLITHIC mm-WAVE PHASED ARRAYS

The range of mm-wave radio communications is severely constrained by high losses arising from the short wavelength and from atmospheric attenuation. Large phased arrays can overcome these limitations, but it is very difficult to realize them using present monolithic beamsteering IC architectures. We propose an alternative architecture for large monolithic phased arrays. The beam is steered in altitude and in azimuth by separately imposing vertical and horizontal phase gradients. This choice reduces IC complexity, making large arrays feasible. Since extensive digital processing provides robust amplitude control and reduces die area, the LOs are processed as digital signals. Being very sensitive to compression, the IF signals are processed as analog signals and distributed by means of synthetic transmission-line buses. With careful frequency planning, this mixed-signal approach can allow large phased arrays to operate at frequencies much higher than those achievable with pure analog design.