Design of a C-Band Microstrip Voltage Controlled Oscillator Using an Electromagnetic-Harmonic Balance Co-Design Technique

A voltage controlled oscillator (VCO) was designed for operation in C-band for use in a microwave point-to-point radio system. Microstrip technology was chosen for resonator implementation since it offers ease of manufacturing and frequency adjustment The design was performed using an electromagnetic (EM)-harmonic balance co-design technique in order to achieve first pass success. The measured frequency versus tune voltage data shows excellent agreement with simulation. Maximum deviation of 2% between the two was observed. The VCO tuned from 4.3 GHz to 5.4 GHz as the tuning voltage was varied from 0 to 9V representing a tuning bandwidth in excess of 20%. Phase noise over the tune range was better than -108 dBc/Hz at 100 kHz offset.