A Two-path Output Low Phase Noise Local Oscillator for RF Front-end Applications

This article presents the design and test of two-path output local oscillator (LO) module for RF front-end transceivers. The designed local oscillator which is consisted of a phase locked loop (PLL) frequency synthesizer integrated with a two-path 3-dB Wilkinson power divider and amplifiers circuitry. The selected PLL chip integrated voltage-controlled oscillator (VCO) has a coverage frequency of 137.5 ~ 4400 MHz and good open loop phase noise characteristics, which can meet the design requirements well. Good agreement between test measurements and simulation results is achieved. The fabricated LO module has the merits such as high stability, cost-effective design, and low phase noise. The real measured phase noise of oscillation frequency 2.6 GHz at 1 MHz offset is -129.08 dBc/Hz.