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We describe a photoacoustic ultrasonic imaging system that can provide separate acoustic information on a thick substrate and a thin coating simultaneously. This is achieved by generating an ultranarrow longitudinal pulse on the opaque layered sample, and detecting the series of substrate and coating echoes in high time resolution. The echo times, attenuations, and acoustic dispersions in each series provide information on the substrate or coating separately. New photoacoustic images of coatings and of substrates for coated ceramic substrates are presented.

A compact multi-band planar antenna has been developed for mobile wireless terminals.' h i s planar antenna, fabricated on ngtd or flexible dielectnc substrates, is capable of muluband operation that is requred in mobile WI~KICSS temnals such as telephones and personal digital assistants PDAs). Multi-band operation IS obtained by perturbing the shape of a conventional microstnp patch antenna In a prescnbed manner. This highly reliable, low cost antenna offers low profile with no moving parts, and 1s ideally suited for tnstallauon wthm the temunal with no need for external parts. This paper presents the design, I1M analysis, and a complete set of measurements fur the compact multi-band antenna.

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