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

The article presents a Doherty power amplifier (DPA) with both high efficiency and good linearity for GSM base station using LDMOS transistors. Prepositive delay line structure (PDL) is proposed to satisfy the performances, both higher efficiency and better linearity are achieved. The test results show the proposed DPA reached an efficiency of 43.2% and an IMD3 of -47 dBc at 6 dB back-off power, which is about 19% and 6.5 dBc improvement, respectively than the class AB amplifier, and the improvement is about 4% and 12 dBc. respectively compared with the DPA without PDL structure. (C) 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 493-495, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10. 1002/mop.24917