Northrop Grumman Systems Corporation

Trw Limited

David Yip

Alvin M Kong

Thomas Jung

Rahil U Bhorania

A multi-channel surface acoustic wave (SAW) filter includes a voltage controlled velocity tunable piezoelectric substrate, an input transducer fabricated on the substrate, and an output transducer fabricated on the substrate. The input transducer further includes multiple input sub-transducers that are electrically and physically connected in parallel. The output transducer further includes multiple output sub-transducers that are electrically and physically connected in parallel. Corresponding pairs of input sub-transducers and output sub-transducers form multiple parallel channels for SAW propagation. The input transducer produces a voltage controlled tunable COMB frequency response that is combined with a voltage controlled tunable COMB frequency response produced by the output transducer to produce a SAW filter voltage controlled tunable frequency response. Further embodiments include a multi-channel SAW resonator, a SAW filter device connecting two novel SAW filters in series, and a SAW filter device connecting two novel SAW resonators in series.

Multi-channel surface acoustic wave filter device with voltage controlled tunable frequency response

A micro electromechanical system (MEMS) switch () includes a substrate () and a stress free beam () disposed above the substrate (). The stress free beam () is provided within first and second platforms () to limit displacement of the stress free beam () in directions that are not substantially parallel to the substrate (). A set of one or more control pads () is disposed in a vicinity of a first lengthwise side () of the stress free beam () for creating a potential on the first lengthwise side () of the stress free beam (). The stress free beam () is displaceable in directions substantially parallel to the substrate () in accordance with the potential for providing a signal path.

Anchorless electrostatically activated micro electromechanical system switch

A reflective grating () for a SAW filter () or resonator. The reflective grating () is formed by selectively dithering grating grid lines () with respect to a uniform spaced grid of M number of grid lines () per each N wavelength (&#x3bb;) of the grating () (N&#x3bb;/M), where &#x3bb; is the wavelength of the center of the frequency band of interest, M and N are integers and M&#x3e;N. M and N are selected so that the grating () does not have a net reflection when all of the grid lines () are uniformly spaced. By controlling the dithering pattern of the grid line in each sampling period of N&#x3bb;, any desired net distributed reflectivity from the grating can be implemented in both magnitude and phase.

Weighted SAW reflector grating using dithered acoustic reflectors

A cascaded SAW filter system includes first and second SAW filters ( ) each including an input transducer ( &prime;) and an output transducer ( &prime;) on a piezoelectric substrate ( &prime;). Group delay and pass band ripples associated with a time spur at TD&prime; away from the main signal of the second filter ( ) cancel the group delay and pass band ripples associated with a time spur at TD away from the main signal of the first filter ( ) because: 1) the input and output transducers ( &prime;) of the second filter ( ) are offset from those of the first filter ( ); 2) the center frequency (f &prime;) of the second filter ( ) is offset from the center frequency (f ) of the first filter ( ); 3) the perturbation region (P ) of the first filter ( ) is different from the perturbation region (P ) of the second filter ( ) or 3) a combination of 1), 2) and/or 3. The associated time spur echo of the cascaded response will also be canceled. Also, time spurs due to reflections from the ends of the input and output transducers of the first and second filters ( ) can be cancelled by adding dummy fingers ( ) at each end of the input arid output transducers of the second filter.

Cascaded surface acoustic wave filter system for cancelling time spurious responses

The invention relates to a new family of surface acoustic wave single-phase unidirectional transducers (SPUDTs) by using M uniform width, uniformly spaced, single-level interdigitated electrodes lying on a uniform grid of a piezoelectric substrate where unidirectionality is achieved by selectively etching reflective structures into the substrate either in the spaces located between adjacent electrodes or under selected electrodes of the transducer. A SAW filter, resonator or delay line can also be formed by fabricating two such transducers on a single substrate, each having surface acoustic waves radiating towards the other.

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La Mirada, CA, United States of America

David Yip