A 0.6-THz Area-Efficient Source Based on Parallel Coupled Oscillators and a Bandwidth Expanded Differentially-Fed Shared Aperture Patch Antenna

A differentially-fed shared aperture patch antenna with on-chip power combining and radiation function is proposed for a compact terahertz (THz) source design. The input impedance of the antenna can well match with the transistor over an extended bandwidth for high-efficiency third harmonic extraction by the proposed feeding method. A high-density parallel coupled oscillator topology is proposed to feed the antenna for realizing high area efficiency. The single patch-antenna-based source can easily feed a low-cost Teflon lens for high-EIRP radiation. A prototype is designed and fabricated in 65-nm CMOS technology with a 0.216 mm(2) core area. A peak-radiated power of -3.7 dBm is measured at 600.5 GHz under 304-mW power consumption, realizing a 0.139% dc-to-THz conversion efficiency and a 1.95 mW/mm(2)corearea efficiency. By adding the lens, a peak EIRP of 29.6 dBm is measured. The frequency tuning range of the source is 4.9%, from 584.8 to 614.3 GHz. At 602.2 GHz, the measured phase noise at 1-MHz offset is -75.3 dBc/Hz.