A 350-GHz Coupled Stack Oscillator with −0.8 dBm Output Power in 65-nm Bulk CMOS Process

Thanh Dat Nguyen ,Jong-Phil Hong

doi:10.3390/electronics9081214

Abstract

This paper presents a push-push coupled stack oscillator that achieves a high output power level at terahertz (THz) wave frequency. The proposed stack oscillator core adopts a frequency selective negative resistance topology to improve negative transconductance at the fundamental frequency and a transformer connected between gate and drain terminals of cross pair transistors to minimize the power loss at the second harmonic frequency. Next, the phases and the oscillation frequencies between the oscillator cores are locked by employing an inductor of frequency selective negative resistance topology. The proposed topology was implemented in a 65-nm bulk CMOS technology. The highest measured output power is −0.8 dBm at 353.2 GHz while dissipating 205 mW from a 2.8 V supply voltage.

Highlights

The terahertz (THz) frequency range, which is from 300 GHz to 3 THz, has recently gained much attention from researchers due to its wide range of applications such as high-speed communication, imaging security system, and spectroscopy [1,2]
The proposed oscillator was fabricated in a 65 nm bulk CMOS process
The Farran WR-2 down-conversion is a harmonic mixer with interface WR2 has a function of down-converting the frequency of the input signal by mixing input signal with a local oscillator (LO) signal

Summary

Introduction

The terahertz (THz) frequency range, which is from 300 GHz to 3 THz, has recently gained much attention from researchers due to its wide range of applications such as high-speed communication, imaging security system, and spectroscopy [1,2]. In these applications, a high power and high frequency signal source is one of the most important components to create a system with superior quality. CMOS signal sources present some difficulties such as low maximum oscillation frequency (fmax ) and low output power at the THz frequency range.

The Proposed Signal Source

Measurement Results

Conclusions