The new RTD-HBT differential oscillator circuit topology is proposed. At the nodes of the inductors and varactors in the conventional differential oscillator topology, each the RTD is attached to increase the magnitude of the negative conductance, which results in performance improvement in both the RF output power and phase noise. And, the differential sinusoidal voltage waveform which is essential for the wireless communication system are generated. In addition, the DC power consumption RTD-HBT differential oscillator circuit is similar to the conventional HBT differential oscillator due to the small DC power consumption performance of the RTD.