Robert B. Stokes

X-band thin film acoustic filters on GaAs

The semiconductor bulk acoustic resonator (SBAR) is composed entirely of thin films, piezoelectric aluminum nitride, and metal electrode films (primarily aluminum). The authors describe the performance of an SBAR filter which has only 6.1 dB insertion loss at 7.8 GHz (2nd harmonic) and 7.5 dB insertion loss at 11.6 GHz (third harmonic), with fractional bandwidths less than 1%. This filter demonstrates that SBAR technology is practical for X-band filters in MMICs (monolithic microwave integrated circuits).<<ETX>>

Parallel-to-serial signal processor using surface acoustic waves

A surface acoustic wave (SAW) device for converting multiple parallel signals to a smaller number of serial signals. The device includes a piezoelectric substrate and a surface acoustic wave (SAW) input transducer for propagating periodic surface acoustic waves across the substrate. The parallel signals are input to the device through an array of acoustic charge transport (ACT) input transducers, which convert the signals into packets of electrical charge that are transported across the device with the surface acoustic waves generated at the SAW input transducer. An ACT output transducer converts the charge packets back into electrical signals, but in serial rather than parallel form. The converter of the invention can be usefully combined with a SAW channelizer or spectrum analyzer, to provide serial outputs from the analyzer.

Recent Developments in SAW Device Applications

This paper discusses recent developments in SAW applications by first reviewing the range of parameters achievable using current state-of-the-art devices. Examples of device applications in filtering, frequency sources and signal processing are then presented to provide an overview of how SAW devices are being utilized in various commercial and military electronic systems.