Design of X-band VCO for marine radar product

The authors explain the design approach of a VCO using linear simulation. The design method uses measured S-parameters for the active device of the oscillator and then, employs computer simulation to optimize the oscillator circuit to satisfy the oscillation conditions. The oscillator was fabricated using a GaAs-FET and Si abrupt junction varactor diode on Duroid substrate. The tested prototype achieved tuning frequencies from 9.2 to 9.5 GHz, and provided output power of approximately 14 dBm over the frequency band. The oscillator was tested under temperature from -20°C to 60°C and the performance was excellent. The simulated and measured results are presented