Abstract: A directional coupler comprising a dielectric substrate having two opposing faces carrying a sheet electrode on one face and two comb like electrode structures on the other face. Each comb electrode has finger like electrodes projecting from a bus bar towards the other comb. Varying the length of finger electrodes and the amount of overlap varies the amount of signal power coupled between the two combs. Couplers may be arranged to couple up to 100% of signal power. When half signal power is coupled, a 3dB coupler, various microstrip circuits may be built e.g. balanced mixers, power dividers, or power combiners.

Abstract: A surface acoustic wave device comprises a piezoelectric substrate which carries input and output transducers for launching and receiving surface acoustic waves on the substrate, one or more reflective arrays for reflecting surface acoustic waves between the two transducers, wherein at least one array comprises numerous spaced reflecting elements of varying lengths arranged in two sets, one set being angled to reflect surface acoustic wave in one direction while the other set is angled to reflect surface acoustic wave in another direction. Varying the lengths of the reflecting elements provides weighting of signals passing through the device. Additionally pulse compression and expansion may be arranged with or without frequency dispersion.

Abstract: A surface acoustic wave device comprises a substrate able to support surface acoustic waves, an input transducer for launching surface acoustic waves along a first track on the substrate, an output transducer for receiving surface acoustic waves from a second track on the substrate, and first and second reflective array structures arranged to reflect surface acoustic waves from the first track into the second track, the first and second reflective array structures each comprising numerous reflecting strips or grooves arranged parallel to one another in echalon across the first and second tracks respectively. Varying the lengths of the reflecting elements provides weighting of signals passing through the device, and varying the spacing between the reflecting elements provides pulse compression or expansion with a frequency sweep.