A study of superharmonic injection locking in multiband frequency dividers

Abstract

A superharmonic voltage-controlled injection-locked frequency divider, implemented using a modified Colpitts oscillator operating at 2.5, 5 and 10 GHz and a cross-coupled LC oscillator operating at 1.25, 2.5 and 5 GHz, is demonstrated. The proposed triple-band operation is achieved by employing a novel technique that uses pin-diodes and negative power supply. The discrete dividers, built with low noise hetero-junction FETs and high-frequency SiGe BJTs, are described theoretically while their functionality is proven experimentally. Additionally, a short phase noise analysis, which is missing in the literature, is given. Phase noise, frequency range of operation, and locking range measurement results are presented. Finally, post-layout simulation results of a 5 GHz fully differential injection-locked frequency divider, implemented in a 0.25 mu m SiGe process are provided. Copyright (C) 2010 John Wiley & Sons, Ltd.