A Simple Low-Noise Subharmonically Injection-Locked Oscillator for Low-Cost RF Synthesizers and Front-Ends for Wireless Communications

In this paper, a simple 2.095GHz subharmonically injection-locked oscillator (ILO) using HBT transistor is presented. A subharmonic signal of 1.0475GHz frequency is injected to the oscillator to lock the oscillation at 2.095GHz. With the capacitive feedback impedance at the transistor emitter, and inductive load and the resonator at the transistor base, a low phase noise of –92 dBc/Hz at the 10KHz offset was obtained. Simulation results show that the phase noise of the oscillation output is only about 0.5dB higher than that of the injected signal. Such a low noise feature has presented potentials in developing RF synthesizer and front-ends for low-cost wireless and mobile communication transceivers.