A new SAW-resonator with electronically switchable resonance frequency

A new two-port SAW-resonator is presented. Its transmission frequency can be switched between two discrete resonances by changing the electrical termination of additional transducers within the resonator's cavity. This can be done by mechanical switches or by FETs which allow for electronical switching with low power consumption. The device can be applied to provide a simple change of a transmitters carrier frequency. It may be also used for low-cost, low-bit-rate frequency shift keying transmission systems. Extending the principle to more than two resonances a switchable oscillator for channel selection can be realized. In this case an advantageously low oscillator's phase noise is achieved. This is due to the high quality factor of SAW-resonators.