A Temperature Compensated High Voltage Probe Using Surface Acoustic Waves

We have investigated controlling the phase velocity of a surface acoustic wave (SAW) by a microelectromechanical switch fabricated on a high coupling piezoelectric substrate. The principle is based on the interaction of the evanescent surface potential of the SAW with the conductive switch. In theory tuning of the velocity in the range given by v0 and vm, i.e. the velocity for a SAW on a free and metallized substrate, is possible. We have achieved up to 17.6 m/s (0.44 %) velocity tuning on 128degYX LiNbO3. A maximum velocity sensitivity of Deltav/v of 15times10-3/V and phase sensitivity of 700deg/V was measured. This is five orders of magnitude larger than values obtained for electrical field tuning.

P0-13 Phase Velocity Control of Surface Acoustic Waves Based on Surface Shorting and Electrical Field Application Using MEMS Switches

New Configuration for Electronically Variable SAW Delay Line

A SAW Probe for Time Variable High Voltage Measurements

The design of a selectable performance front-end filter using acoustic surface waves is currently underway. The filter is being designed to allow for selectable center frequency and bandwidth, ideally while maintaining 3 dB insertion loss. This paper explains the theory of operation of the device, and discusses how the critical design goals map into an acoustic surface wave implementation.

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Design of a selectable performance front-end filter using acoustic surface waves

Experimental Results The influence of a biasing electric field on the propagation of surface acoustic waves in LiNbO?, LiTaOg, and PbTi03 ceramic substrates is experimentally investigated. The 128" rotated Y- cut, X-propagating orientation of LiNb03 shows a linear and fairly large variation of time delay with the biasing field. Fractional time delay changes greater than 9xlO* have been obtained, and values upto 0.16 percent appear possible in SAW devices fabricated on this material. These changes in time delay are adequate to make the technique useful for several applications. Possible applications of this effect for beam steering in phased array antennas, measurement of high voltages, and temperature compensation in SAW devices are discussed.

http://ieeexplore.ieee.org/iel5/10281/32714/01534573.pdf

B.B. Dasgupta

Papers

Electronically Variable Surface Acoustic Wave Time Delay Using a Biasing Electric Field