A 0.46-THz 25-Element Scalable and Wideband Radiator Array With Optimized Lens Integration in 65-nm CMOS

Abstract

In this article, we present a 438-479-GHz fully integrated 25-element radiator array source based on a scalable structure of coupled standing wave oscillator cells without extra loss and parasitics from coupling networks. The bandwidth is extended using a varactor-less frequency tuning method, and EIRP is improved by increasing the size of the array using the proposed scalable coupling method and maximizing the radiation directivity using a silicon lens in an optimized radiation setup. An analysis of the radiation directivity of a chip-lens setup is presented as well as the employed approach for enhancing EIRP by maximizing the directivity. The circuit is implemented in a 65-nm CMOS process and is measured to have 40.7 GHz/8.9% frequency tuning range. The chip consumes 0.38-2.34-W power (1.18 W at 459-GHz center frequency) from a 1.2-V supply voltage. The circuit provides a maximum of -1.8-dBm radiated power and 19.3-dBm EIRP at 448 GHz using a 12.5-mm radius silicon lens. The minimum measured phase noise at 10-MHz offset is -100.6 dBc/Hz. To the best of our knowledge, this article has the largest EIRP, radiated power, and bandwidth among fully integrated silicon-based coherent sources above 350 GHz.