Mutual Synchronization for Power Generation and Beam-Steering in CMOS with On-Chip Sense Antennas Near 200 GHz

In this paper, we introduce the concept of near-field synchronization as an efficient, scalable, and robust method to synchronize a 2-D array of mutually coupled oscillators for beam-forming at frequencies above f_max of a technology. The method employs an array of on-chip sense antennas to probe electromagnetic near-fields of the on-chip radiators. These sense antennas are then coupled to each other appropriately through a network that establishes the synchronized state as the lowest energy state. A circuit-electromagnetic co-design methodology is employed to demonstrate beam-steering near 200 GHz with a synchronized 2×2 array. Each element of the array is a traveling-wave oscillator with the nonlinear active devices selectively radiating its second harmonic through the same electromagnetic structure. The beam-pattern can be varied by more than 70° in both azimuth and elevation. The chip is realized in 65-nm bulk CMOS.