Texas Instruments Corporation

Robert S Wagers

Clinton S Hartmann

Donald C Malocha

Jeffrey H Goll

The disclosure relates to a microstrip circuit which is used to combine the energy output from the convolving plate of a surface acoustic wave (SAW) monolithic elastic convolver. The convolving plate is tapped at its two ends and a Wilkinson combiner is used to sum the signals that propagate to the ends of the plate. The Wilkinson combiner is a three-port device with the two arms that couple to the convolver plate having their characteristic impedances set to match that of the acoustic waveguide. In view of the impedance match, no electromagnetic reflections are produced at the end of the convolving plate and all of the energy incident on the Wilkinson combiner is summed and delivered to the output port of the combiner. Additionally, the microstrip circuit has an impedance transformer to transform down to an impedance suitable for driving an output amplifier chain of a receiving system. In accordance with a second embodiment of the invention, a plurality of convolvers is connected together in a Christmas tree-type of arrangement to maintain spatial amplitude uniformity while minimizing the phase delay that occurs from propagation from the center of the elastic convolver to the outer extremes thereof. In accordance with a third embodiment of the invention, the Wilkinson convolvers of FIG. 2 are replaced by microstrips configured to sum the outputs from all of the convolver sections without reflections. This embodiment provides an impedance matched to the driving segments of the convolving plate and produces broad band power combining internal to the microstrip of the output circuit. This embodiment eliminates potential losses within the microstrip circuit from power dissipation in lumped resistors inherent in the Wilkinson embodiment.

Monolithic elastic convolver output circuit

An optical spatial address system wherein a collimated light beam which is deflectable in a predetermined manner strikes a backdrop having one or more sets of reflecting facets thereon to direct the beam to a unique point in a three-dimensional space as defined by the predetermined deflection of the light beam for the case of two sets of facets. The facets are designed to preferably direct the beam from the source from the first set of facets along an axis in three-dimensional space to the second set of facets, the latter facets directing the beam along an axis orthogonal to the direction of the beam impinging thereon.

Optical spatial address system suitable for flat panel displays and the

A broad band surface acoustic wave (SAW) device has an edge-deposited transducer (EDT) capable of frequencies in excess of 1 GHz and bandwidths in the hundreds of MHz. The device includes a transducer on a semiconductor substrate which is either non-piezoelectric or weakly piezoelectric. The substrate has a sharp, smooth edge formed by the intersection of its top and a side surface. The transducer includes a passivation layer deposited on the side surface of the substrate and a starter layer deposited on the passivation layer; an inner metallic (gold, for example) electrode deposited on the starter layer; a transducer layer deposited on the inner metallic electrode; and an outer metallic electrode deposited on the transducer layer. The outer electrode is formed on the transducer layer one-fifth wavelength below the top surface of the substrate. When the transducer is excited, bulk longitudinal waves are generated in the transducer layer which couple to the longitudinal component of the surface wave in the substrate causing the SAW mode to propagate away from the transducer.

Broad band surface acoustic wave edge deposited transducer

A structure for compressing an acoustic surface wave into a symmetric higher energy density output surface acoustic wave. Conductive strips are placed in parallel upon a piezoelectric surface. When a symmetric input is generated at one side of the multistrip coupler, the energy of the input wave is compressed into the center channel and is presented at the output in a single moded symmetric form.

Symmetric beam width compression multistrip coupler

An improved acoustic waveguide structure which comprises a ridge waveguide disposed in a horizontal direction extending outwardly from a substrate. The horizontal orientation of the waveguide which is in the form of a ledge results in particle motion of the ledge predominantly normal to the substrate plane with the largest motion at the free edge of the ledge and almost no motion in the substrate, thereby permitting a plurality of such structures to be densely packed on a common substrate.

Acoustic ridge interactive structure

Acoustic waveguide resonator

Acoustic ridge delay line

Acoustic ridge transversal filter

This disclosure concerns a particularly oriented plate-like monocrystalline piezoelectric body of lithium niobate for use as a substrate in an acoustic surface wave filter device, wherein the orientation of the piezoelectric body of lithium niobate is responsible for a substantial reduction in spurious responses including plate modes. More specifically, the piezoelectric body comprises a plate of lithium niobate having a crystalline lattice orientation as determined by a 46.degree. (ZYW) cut. It has been determined that such a piezoelectric body may be employed as a substrate in an acoustic surface wave filter device to effect an improved filter response in that unwanted spurious responses including those caused by plate modes are removed or substantially reduced from the acoustic signals prior to their conversion into electrical output signals.

Growing community of inventors

Richardson, TX, United States of America

Robert S Wagers