A 5.84 GHz tunable SAW oscillator with frequency doubler for a DSRC system

A varactor tuned oscillator with an external SAW resonator and integrated frequency doubler is developed on a low cost 0.8 /spl mu/m SiGe BiCMOS technology for a DSRC application. The measured phase noise is -95.5 dBc/Hz at 10 kHz offset on a single-ended 50 /spl Omega/ load. A PMOS accumulation-mode varactor is used for the fine tuning of the oscillation frequency within a tuning range of 800 kHz. Furthermore a 2/sup nd/ not tunable oscillator is fabricated with an improved phase noise of -105.65 dBc/Hz at 10 kHz offset. Frequency doubling is achieved by using two unbalanced emitter coupled pairs with a fundamental frequency rejection of better than 20 dBc.