SAW coupled resonator oscillator technology

Oscillator design enhancements using a SAW (surface acoustic wave) coupled-resonator filter (CR) are presented. The CR oscillator provides advantages in size, manufacturing, phase noise, and vibration performance. No impedance matching networks are required with a CR to provide the correct conditions for oscillation. A CR has twice the phase slope of standard resonators which provides 6-dB improvement in phase noise, and the bandwidth is controllable, making it an excellent choice for voltage-controlled applications. Two different types of hybrid SAW CR oscillators are examined: a 318-MHz fixed-frequency oscillator using an integrated circuit in a TO-39 package, and a 1-GHz voltage-controlled oscillator with discrete components. The voltage-controlled SAW CR oscillator has a package size of 1.27*0.77*0.25 in and a phase noise floor of -160 dBc at 200 kHz. The CR voltage-controlled SAW oscillator is compared to standard resonator and delay-line oscillators.<>