A low phase noise EQM(Engineering Qualified Model) LO(Local Oscillator) has been developed for Ka-band satellite transponder. A VCDRO(Voltage Controlled Dielectric Resonator Oscillator) is also designed using a high impedance inverter coupled with dielectric resonator to improve the phase noise performances out of the loop bandwidth. The mechanical analysis fur housing and the thermal analysis fur circuit board are achieved. This EQM LO is applied to Ka-band satellite transponder of EQM level after environmental experiments for space application. The LO has the harmonic suppression characteristics above 52 ㏈c and requires low power consumption under 1.3 watts. The phase noise characteristics are exhibited as -101.33 ㏈c/㎐ at 10 ㎑ offset frequency and -114.33 ㏈c/㎐ at 100 ㎑ offset frequency, with the output power of 14.0 ㏈m${pm}$0.17 ㏈ over the temperature range of -15∼＋65$^{circ}C$.