A 1.12 GHz TO 2 GHz wide-tuning-range VCO with dynamic coupling structures

This paper presents a continuous wide-tuning-range VCO with 56.4% frequency tuning ratio (FTR). Both a dynamic coupling resonator structure and a dynamic feedback amplifying circuit are proposed to maintain the wide-tuning range for the VCO. The dynamic coupling promises stable loaded Q factor and wider tuning range, while the dynamic feedback amplifying circuit assured the oscillating condition across the large frequency tuning range. There are three voltage tunable structures in the proposed, all of which are controlled by the same tuning voltage, so it is easy to be controlled and can be phase locked by a phase-lock-loop (PLL). The VCO results in a tuning range from 1.12 GHz to 2.00 GHz at 0 approximate to +5 V tuning voltage. The measured output power is 4.0 approximate to 6.37 dBm within the tuning range. The measured phase noise is -94.24 approximate to -98.66 dBc/Hz at 100 kHz frequency offset and -118.07 approximate to -123.41 dBc/Hz at 1 MHz frequency offset respectively within the tuning range. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1525-1529, 2016