A 0.1–9-GHz Frequency Synthesizer for Avionic SDR Applications in 0.13-μm CMOS Technology

Abstract

This article describes a design for a frequency synthesizer architecture based on a phase-locked loop (PLL) for avionic software-defined radio (SDR) applications at up to 9 GHz. Three basic architectural schemes: wide range voltage-controlled oscillator (VCO), single sideband (SSB) mixing, and multiple VCOs can be used to extend the frequency ranges. This article compares these schemes through quantitative evaluation to select the best synthesizer architecture to use according to the application specs. The chosen scheme is an optimized combination of a single VCO and a single SSB mixer. Using a quadrature VCO (QVCO) with a switched capacitor (SC) bank, the synthesizer provides a wide frequency band of operation ranging from 100 MHz to 9 GHz covering several avionic communication applications and several existing wireless standards’ frequency requirements. The proposed QVCO is able to generate in-phase and quadrature-phase signals spread into a frequency band between 6 and 9 GHz providing a tuning range of 40% at a center frequency of 7.5 GHz. The QVCO exhibits a phase noise of −107 dBc/Hz, at a 1-MHz offset frequency, while generating a 8-GHz carrier frequency. Its power consumption is of 3.4 mW. With a loop bandwidth of 120 kHz, the frequency synthesizer generates a phase noise, measured at 8 GHz, of −106.4 dBc/Hz at a 1-MHz frequency offset. The overall power consumption of the synthesizer to generate a 140-MHz carrier frequency is 26.57 mW from a 1.2-V supply. The frequency synthesizer is implemented in 0.13- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS technology and occupies an active area of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.72 \times 0.72$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .