%0 Journal Article %T Performance and Trends in Millimetre-Wave CMOS Oscillators for Emerging Wireless Applications %A Marius Voicu %A Domenico Pepe %A Domenico Zito %J International Journal of Microwave Science and Technology %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/312618 %X This paper reports the latest advances on millimeter-wave CMOS voltage-controlled oscillators (VCOs). Current state-of-the-art implementations are reviewed, and their performances are compared in terms of phase noise and figure of merit. Low power and low phase noise LC-VCO and ring oscillator designs are analyzed and discussed. Design and performance trends over the last decade are provided and discussed. The paper shows how for the higher range of millimeter-waves (>60£¿GHz) the performances of ring oscillators become comparable with those of LC-VCOs. 1. Introduction In the last few years several standards have been, or have been planned to soon be, released, regarding millimetre-waves (mm-waves, i.e., 30¨C300£¿GHz) systems for emerging wireless applications. Some of the most attractive applications are 60£¿GHz unlicensed wireless data communication [1], 77-GHz automotive radars [2], and 94£¿GHz passive imaging [3]. Key enabler for high-volume and low-cost mass market implementation of these systems is the significant improvement of device performance in the latest CMOS technology nodes (i.e., 130£¿nm and smaller), which offer a great potential for the realization of millimeter-waves wireless transceivers on a single chip. One of the most important building blocks in a wireless transceiver is the frequency synthesizer. Performance of the voltage controlled oscillator (VCO) dictates the performance of the frequency synthesizer and thus of the whole communication system. The aim of the present paper is to provide a review of the state-of-the-art (SoA) of millimeter-wave (mm-wave, 30¨C300£¿GHz) VCOs in CMOS technology in order to identify the trends over the last decade and derive some useful observations regarding the past and possible future evolution of design and performance. In particular, the paper reports a comparison of performances among SoA design solutions and highlights the achievements and trends in terms of phase noise (PN) and figure of merit (FOM). The present paper is organized as follows. Section 2 provides an overview of two of the most widespread VCO topologies, LC-tank, and ring oscillators and recalls briefly their main causes responsible for the phase noise. In Section 3, SoA millimeter-wave CMOS LC-VCO and ring oscillator design solutions are reported, and their performances are discussed and compared. In Section 4, the conclusions are drawn. 2. CMOS VCOs The most widespread CMOS VCO topologies at mm-wave frequencies are LC-tank and ring oscillators. Section 2.1 provides a brief overview of LC-VCOs and their PN contributions. Section 3.1 %U http://www.hindawi.com/journals/ijmst/2013/312618/