A 0.68-0.72-THz 2-D Scalable Radiator Array With-3-dBm Radiated Power and 27.3-dBm EIRP in 65-nm CMOS

作者：Gao, Liang; Chan, Chi Hou^*

来源：IEEE Journal of Solid-State Circuits, 2022, 57(10): 3114-3124.

DOI：10.1109/JSSC.2022.3178721

• CMOS
• coherent source
• harmonic oscillator
• on-chip antenna
• scalable radiator array
• Teflon lens
• terahertz (THz) source
• third harmonic

A novel and compact 2-D scalable architecture of coupled harmonic oscillator array is proposed for high-power radiation beyond 600 GHz. The compact and symmetric scalable unit cell comprises two oscillators with two slot antennas radiating the third-harmonic power. Each unit cell is horizontally coupled out-of-phase and vertically in-phase with adjacent cells at the fundamental frequency. Therefore, coherent radiation and power combining are achieved at the third harmonic. A 4 x 4 array prototype (32 radiating elements) is designed and fabricated in a 65-nm CMOS technology. An elliptical Teflon lens is attached at the backside of the chip for a highly directive beam. An effective isotropic radiated power (EIRP) of 27.3 dBm and an output power of -3 dBm are measured at 694-GHz with 754-mW power consumption under 1.2-V supply voltage, implying a dc-to-terahertz (THz) efficiency of 0.066%. The core design occupies a chip area of 0.61 mm(2), and the entire chip area is 0.97 mm(2), leading to a 0.52-mW/mm(2) area efficiency. The peak EIRP of 27.8 dBm and the radiated power of -2.4 dBm are measured at 699 GHz under 1.3-V supply voltage. A frequency tuning range of 5.26% from 679.4 to 716.1 GHz is measured by varying bias and supply voltages. The measured phase noise at 1-MHz offset is -73 dBc./Hz at 694 GHz. To the best of our knowledge, the designed array has the highest radiated power, radiated power per area, EIRP, frequency tuning range, and dc-to-THz efficiency among silicon-based scalable coherent radiator arrays operating beyond 600 GHz.