Paul Francis Carr

US Patent:

46098437, Sep 2, 1986

Filed:

Feb 26, 1985

Appl. No.:

6/705060

Inventors:

Paul H. Carr - Bedford MA
Jose H. Silva - Bedford MA

Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC

International Classification:

H01L 4108

US Classification:

310313A

Abstract:

The 19. 1 propagation X-cut of berlinite (AlPO. sub. 4) has been discovered to have cubic temperature compensation for surface acoustic waves (SAW). The temperature variations of frequency or time delay over a 35. degree. to 85. degree. C. temperature range are comparable to ST-quartz. However, berlinite has at least twice the piezoelectric coupling. This is essential for low insertion loss, broadband SAW devices such as filters and correlators. In addition, 19. 1 propagation, X-cut berlinite has lower volume wave spurious than ST-cut quartz.

US Patent:

61779091, Jan 23, 2001

Filed:

Nov 4, 1999

Appl. No.:

9/433762

Inventors:

James R. Reid - Cambridge MA
John S. Derov - Lowell MA
Paul H. Carr - Bedford MA

Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC

International Classification:

H01Q 138

US Classification:

343700MS

Abstract:

A reconfigurable photoconducting antenna is created on a semiconductor substrate. At equilibrium, the semiconductor is semi-insulating, and therefore appears as a dielectric. Illuminating a region of the substrate results in the generation of free carriers in the substrate and allows the creation of a conductive region (semi-metallic) in the substrate. This conductive region functions as the radiating element of the antenna. Controlling the pattern of the illuminated region directly controls the pattern of the radiating antenna. By using a digital micromirror device (DMD. TM. ) to control the pattern of the light, a desired antenna design may be placed on the semiconductor substrate. The pattern can be dynamically adjusted simply by changing the position of the individual mirrors in the DMD. TM. array. The device operates through a standardized digital interface and can be switched between patterns in a period of approximately 20 microseconds.

US Patent:

39421406, Mar 2, 1976

Filed:

Nov 8, 1974

Appl. No.:

5/522367

Inventors:

Kenneth R. Laker - Arlington MA
Alan J. Budreau - Arlington MA
Paul H. Carr - Bedford MA

Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC

International Classification:

H03H 926
H03H 930
H03H 932
H01L 4108

US Classification:

333 72

Abstract:

The input transducers of a multichannel surface acoustic wave device are electrically connected in a series or series-parallel circuit arrangement and are connected to a single channel electromagnetic wave transmission line through an inductor. The inductance value of the inductor is chosen such that minimum transducer insertion loss is achieved at the center frequency of the midband channel. The circuit arrangement is selected which achieves optimum coupling to the midband channel subject to the constraint that the insertion losses of all the remaining channels, measured at their respective center frequencies, lie at or near the above optimum value within an acceptable prespecified margin.