The improvement of VCO performance based upon in/out common frequency tuning

In this paper, we presented a K-band Voltage Controlled Harmonic Oscillator (VCHO) with novel structure. The proposed VCHO is a structure of two hair-pin resonators placed on input and output of active device. By using in/out common frequency tuning structure, the VCHO produced some advantages of the enhanced characteristics of fundamental frequency suppression as well as the improved second harmonic output power. According to measurement results, it has been shown that a VCHO provide the output power of -2.41 dBm, fundamental frequency suppression of -21.84 dBc, and phase noise of -101.44 dBc/Hz @ 100 kHz. In addition, output frequency range of 10.58 MHz could be obtained with a power variation of +/-0.19 dB over its frequency range with respect to the bias voltage from 0 to -10 V for the varactor diode.