Abstract: A spatial harmonic transducer of a SAW device is made directional for SAWs at a spatial harmonic signal frequency of the transducer by a reflector for reflecting SAWs at that frequency. The transducer comprises repeated groups of consecutive electrodes having a predetermined polarity sequence, positioned to operate coherently for SAWs at the signal frequency. The reflector comprises reflector electrodes for producing constructive and destructive interference in opposite SAW directions, with electrode widths and spacings of at least a quarter wavelength at the signal frequency. A SAW device with two such spatial harmonic SPUDTs using different polarity sequences can provide desirable characteristics for filters and delay lines at frequencies of about 2 GHz.

Abstract: A spatial harmonic transducer of a SAW device is made directional for SAWs at a spatial harmonic signal frequency of the transducer by a reflector for reflecting SAWs at that frequency. The transducer comprises repeated groups of consecutive electrodes having a predetermined polarity sequence, positioned to operate coherently for SAWs at the signal frequency. The reflector comprises reflector electrodes for producing constructive and destructive interference in opposite SAW directions, with electrode widths and spacings of at least a quarter wavelength at the signal frequency. A SAW device with two such spatial harmonic SPUDTs using different polarity sequences can provide desirable characteristics for filters and delay lines at frequencies of about 2 GHz.

Abstract: A device and method used to transmit/receive an input message bearing signal at variable bandwidths using a variable frequency bandwidth control signal as an input for changing the bandwidth of the output signal.

Abstract: A tapered IDT function is provided in an IDT of a SAW device having fingers substantially parallel to one another by applying a static electric field to a piezoelectric substrate of the SAW device to generate in the substrate a strain which varies across the aperture of the IDT, thereby varying a center frequency of the IDT across the aperture of the IDT. The electric field can be perpendicular to the fingers and created by applying a dc voltage between conductors at least one of which can be tapered or angled, either in the region of the IDT to produce a strain directly or adjacent to the IDT to produce a strain indirectly, or it can be parallel to the fingers, two fields with opposite directions being created at the two sides of the IDT.