VCO Cuts Phase Noise While Maintaining Tuning Range

Oct. 22, 2009

GROWTH IN THE WIRELESS-COMMUNICATIONS industry has fed the demand for more available channels in mobile-communications applications. This trend, in turn, has placed stricter requirements on the phase noise of voltage-controlled oscillators (VCOs). At Korea's Soongsil University, Jaewon Choi and Chulhun Seo have developed a VCO that reduces phase noise without lowering the frequency tuning range. This VCO offers phase noise of 127.5 to 126.33 dBc/Hz at 100 kHz from 5.744 to 5.865 GHz.

To suppress phase noise, a harmonic control circuit is given short impedances for the secondand third-harmonic components. Because phase noise is reduced without a high-Q resonator, the frequency tuning range of the proposed VCO is not reduced. To attain better phase noise, the microstrip square open loop multiple split-ring resonator has been used with the proposed harmonic control circuit. See "Low-Phase Noise VCO Using Output Matching Network Based on Novel Harmonic Control Circuit," Microwave And Optical Technology Letters, August 2009, p. 1838.

About the Author

Nancy Friedrich

RF Product Marketing Manager for Aerospace Defense, Keysight Technologies

Nancy Friedrich is RF Product Marketing Manager for Aerospace Defense at Keysight Technologies. Nancy Friedrich started a career in engineering media about two decades ago with a stint editing copy and writing news for Electronic Design. A few years later, she began writing full time as technology editor at Wireless Systems Design. In 2005, Nancy was named editor-in-chief of Microwaves & RF, a position she held (along with other positions as group content head) until 2018. Nancy then moved to a position at UBM, where she was editor-in-chief of Design News and content director for tradeshows including DesignCon, ESC, and the Smart Manufacturing shows.