2-D Direct-Coupled Standing-Wave Oscillator Arrays

A direct-coupled technique for standing wave oscillator (SWO) arrays is presented in this paper. The oscillation currents of a unit cell in the SWO array directly inject to adjacent cells through the resonator. Two 2-D SWO arrays based on the technique are reported. The first SWO array can provide synchronous signals with identical frequencies, amplitudes, and phases at multiple locations over a chip. It is implemented in a 90-nm CMOS technology with 61.5-GHz oscillation frequency. Millimeter-wave radiators that consists of the proposed SWO array, an RF driver array, and an on-chip loop antenna array are implemented in a single chip to verify the synchronicity of the reported 2-D SWO via wireless measurement. The indirect evidence of synchronicity is provided from the correlation between the wireless measured effective isotropic radiated power (EIRP) and phase noise of 1 × 1, 2 × 2, and 3 × 3 arrays. The EIRP in the normal direction of the array is increasing by a factor of 10 log N
²
and the phase noise is reducing by a factor of 10 log N over that of a single cell, where N is the number of unit cells in the array. The second SWO array can provide synchronous signals with identical frequencies, amplitudes, and multiple phases at multiple locations over a chip. It is implemented in a 65-nm CMOS technology with 132.5-GHz fundamental frequency. The SWO array is designed for a 2-D second-harmonic (265 GHz) spatial power radiating and combining array. The EIRPs of the fundamental frequency and second harmonic in the normal direction of the array are -34 and -6.5 dBm, respectively. The phase noise of the fundamental frequency and second harmonic at 1-MHz offset from the carrier frequency are -96 and -89 dBc/Hz, respectively.