A low phase noise common base Colpitts voltage controlled oscillator for satellite communications is presented. The circuit is fully integrated and is fabricated using a space qualified commercial InGaP HBTtechnology. The circuit does not include any custom components since the reliability in space applications is very important and it can only be achieved through library modeled elements. The VCO operates from 3.3 to 3.59 GHz with a 4% tuning range, and with an output power of 0.5 dBm for a frequency of 3.5 GHz. It shows a very good phase noise characteristic, showing -115.5 dBc/Hzat 1 MHz offset in measurements. The overall dc power consumption of the VCO core is quite low, with a value of 32.5mW for a supply voltage of 5 V
