The EM(Engineering Model) LO(Local Oscillator) is designed for Ka-band satellite transponder. The VCO(Voltage Controlled Oscillator) is implemented using a high impedance inverter coupled with dielectric resonator to improve the phase noise performance out of the loop bandwidth. The phase of VCO is locked to that of a stable OCXO(Oven Controlled Crystal Oscillator) by using a SPD(Sampling Phase detector) to improve phase noise performance in the loop bandwidth. This LO exhibits the harmonic rejection characteristics above 43.83 dBc and requires 15 V and 160 mA. The phase noise characteristics are performed as -102.5 dBc/Hz at 10 KHz offset frequency and -104.0 dBc/Hz at 100 KHz offset frequency, respectively, with the output power of 13.50 dBm$pm$0.33 dB over the temperature range of -20~+7$0^{circ}C$.