A 4×4 Distributed Multi-Layer Oscillator Network for Harmonic Injection and THz Beamforming with 14dBm EIRP at 416GHz in a Lensless 65nm CMOS IC

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Integrated high-power THz arrays with beamforming ability can enable new applications in communication, sensing, imaging, and spectroscopy [1]. However, due to the limited power-generation capability of a single source above the device fmax [2], efficient spatial power combining from multiple coherent sources becomes necessary to generate mW level of power. To create this 2D array of distributed frequency and phase-locked sources, prior works have shown central LO-signal distribution with local harmonic upconversion [3]. However, this requires high power consumption in the LO distribution. In addition, phase-matching with PVT variations across the sources at the harmonic-radiating THz frequency can be quite challenging. A small θ perturbation at the fundamental frequency translates to Nθ at the radiated Nth harmonic, thus corrupting the array beam pattern. Another method to synchronize multiple distributed radiating sources (/2 spaced at Nfo) is through a mutual coupling network with active/passive elements in a coupled oscillator array [4], [5]. However, the locking range in these methods is typically narrow (flocking f0/20 to f0/10) and PVT variations can easily cause desynchronization. In such a network, each cell is a self-sustaining oscillator, and the coupling network tries to establish injection signals to force synchronization between these individual free-running oscillators. In this paper, we used a 2D oscillating network with negative Gm(-Gm) cells at each node that do not oscillate individually but only collectively, establishing a robust frequency and phase distribution network across the chip for high THz-power generation. By making this network as the lowest layer, we can now separate the locking mechanism and the power-generation sources. This avoids loading and sub-optimal operation of the power sources. The distributed oscillating network at the lowest layer operates at 69.3GHz, and multi-layer local harmonic generation produces a radiated power of -3dBm and +14dBm EIRP at 416GHz in a 4×4 array.

Original languageEnglish (US)
Title of host publication2020 IEEE International Solid-State Circuits Conference, ISSCC 2020
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages456-458
Number of pages3
ISBN (Electronic)9781728132044
DOIs
StatePublished - Feb 2020
Event2020 IEEE International Solid-State Circuits Conference, ISSCC 2020 - San Francisco, United States
Duration: Feb 16 2020Feb 20 2020

Publication series

NameDigest of Technical Papers - IEEE International Solid-State Circuits Conference
Volume2020-February

Conference

Conference2020 IEEE International Solid-State Circuits Conference, ISSCC 2020
CountryUnited States
CitySan Francisco
Period2/16/202/20/20

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

Cite this

Sengupta, K. (2020). A 4×4 Distributed Multi-Layer Oscillator Network for Harmonic Injection and THz Beamforming with 14dBm EIRP at 416GHz in a Lensless 65nm CMOS IC. In 2020 IEEE International Solid-State Circuits Conference, ISSCC 2020 (pp. 456-458). [9063076] (Digest of Technical Papers - IEEE International Solid-State Circuits Conference; Vol. 2020-February). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/ISSCC19947.2020.9063076