David P Yip

US Patent:

6480076, Nov 12, 2002

Filed:

Dec 21, 2000

Appl. No.:

09/745820

Inventors:

David S. Yip - La Mirada CA
Alvin M. Kong - Manhattan Beach CA
Rahil U. Bhorania - Redondo Beach CA

Assignee:

TRW Inc. - Redondo Beach CA

International Classification:

H03H 964

US Classification:

333193, 333195, 310313 B

Abstract:

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.

US Patent:

6664871, Dec 16, 2003

Filed:

May 16, 2002

Appl. No.:

10/150264

Inventors:

David S. Yip - La Mirada CA

Assignee:

Northrop Grumman Corporation - Los Angeles CA

International Classification:

H03H 900

US Classification:

333194, 333193, 333195, 333196, 333133, 333 30, 333 25, 333 26, 310313 R, 310313 C, 310313 B, 310313 D

Abstract:

A cascaded SAW filter system includes first and second SAW filters ( ) each including an input transducer ( â) and an output transducer ( â) on a piezoelectric substrate ( â). Group delay and pass band ripples associated with a time spur at TDâ 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 ( â) of the second filter ( ) are offset from those of the first filter ( ); 2) the center frequency (f â) 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.

US Patent:

6842091, Jan 11, 2005

Filed:

Feb 28, 2003

Appl. No.:

10/377333

Inventors:

David S. Yip - La Mirada CA, US

Assignee:

Northrop Grumman Corporation - Los Angeles CA

International Classification:

H03H 964
H03H 925

US Classification:

333195, 333196, 310313 D

Abstract:

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 (λ) of the grating () (Nλ/M), where λ is the wavelength of the center of the frequency band of interest, M and N are integers and M>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 Nλ, any desired net distributed reflectivity from the grating can be implemented in both magnitude and phase.

US Patent:

6882256, Apr 19, 2005

Filed:

Jun 20, 2003

Appl. No.:

10/465555

Inventors:

David Yip - La Mirada CA, US

Assignee:

Northrop Grumman Corporation - Los Angeles CA

International Classification:

H01P001/10
H81B007/02
H81B007/04

US Classification:

333262, 333105, 200181

Abstract:

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.

US Patent:

7821360, Oct 26, 2010

Filed:

Aug 28, 2008

Appl. No.:

12/199972

Inventors:

David Yip - La Mirada CA, US
Alvin Kong - Manhattan Beach CA, US
Thomas Jung - Rolling Hills Estates CA, US

Assignee:

Northrop Grumman Systems Corporation - Los Angeles CA

International Classification:

H03H 9/64

US Classification:

333193, 310313 B

Abstract:

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.

US Patent:

20040169570, Sep 2, 2004

Filed:

Feb 28, 2003

Appl. No.:

10/377379

Inventors:

David Yip - La Mirada CA, US
Edward Garber - Los Angeles CA, US
Alvin Kong - Manhattan Beach CA, US

International Classification:

H03H009/64

US Classification:

333/195000, 310/31300D

Abstract:

A dual track SAW reflector filter () including a first track () and a second track (). The first track and the second track () include an input transducer (), an output transducer (), first reflectors () and second reflectors (). The reflectivity function of the first reflectors () and the second reflectors () are equal in magnitude and opposite in phase. The input transducers () have the same polarity and the output transducers () have opposite polarities. Surface acoustic waves produced by the input transducers () and received directly by the output transducers () are in phase and cancel at the output transducers (). Surface acoustic waves reflected by the reflectors (and ) are in phase and add at the output transducers ().