James R Howell

US Patent:

6633744, Oct 14, 2003

Filed:

Oct 12, 1999

Appl. No.:

09/415960

Inventors:

James M. Howell - Woodstock GA

Assignee:

EMS Technologies, Inc. - Norcross GA

International Classification:

H04B 7185

US Classification:

455 121, 455 132, 455 133, 343757, 343908, 343909

Abstract:

A ground-based antenna for use with a satellite communications (SATCOM) system that reduces interference from geosynchronous earth orbit (GEO) satellites. Because GEO satellites that provide coverage of the continental United States (CONUS) are uniformly separated along an equatorial arc around the earth, the GEO satellites are approximately uniformly separated in sine space when viewed from a ground terminal located within CONUS over typical communications frequency bands, such as the Ka band (29-39 GHz) and the Ku band (10-15 GHz). The invention can reduce interference by providing an uniformly illuminated rectangular aperture, in which the horizontal dimension is chosen so when the aperture is normal to a transmission axis between the antenna and the Nth satellite of a SATCOM systems, the nulls of the antenna radiation pattern align with the NÂ1, NÂ2, NÂ3,. . . satellites. Additionally, the uniformly illuminated rectangular aperture provides the highest illumination efficiency, which has a distribution of sin(x)/x.

US Patent:

6704543, Mar 9, 2004

Filed:

May 23, 2000

Appl. No.:

09/576475

Inventors:

Thomas E. Sharon - Duluth GA
Thomas S. Taylor - Atlanta GA
William R. Hafner - Alpharetta GA
Steven H. Rigg - Norcross GA
James M. Howell - Woodstock GA

Assignee:

EMS Technologies, Inc. - Norcross GA

International Classification:

H04B 7185

US Classification:

455 121, 455 131, 455427, 455429

Abstract:

A satellite communications system having ground user terminals, hubs, and a geosynchronous satellite. The satellite generates a network of spot beam coverage areas on the earth. A hub and at least one ground terminal are located in each of at least two spot beams. A first user terminal transmits an uplink signal according to a first signal protocol to the hub through the satellite. A second user terminal receives a downlink signal according to a second signal protocol through the downlink spot beam from the hub through the satellite. The hub may be located in the same spot beam coverage area as the first or the second user terminal or may be located in an altogether different spot beam coverage area. Through selective frequency and/or polarization routing on board the satellite, a hub located within a âparentâ beam can communicate with user terminals within the parent beam at a specified frequency and polarization, and can communicate with users in other âdependentâ beams on a different frequency and/or polarization. This routing allocates the total available bandwidth between parent and dependent beams.

US Patent:

6784838, Aug 31, 2004

Filed:

Nov 8, 2002

Appl. No.:

10/290996

Inventors:

James M. Howell - Woodstock GA

Assignee:

EMS Technologies, Inc. - Norcross GA

International Classification:

H01Q 300

US Classification:

342377, 4555621

Abstract:

A phased array antenna system that is operative to simultaneously form multiple beams without requiring an undue amount of hardware. The system collects propagating energy with a number of antenna elements to form multiple beams, encodes the beams as the energy is collected, combines the encoded beams, and then decodes the combined signal to separate the beams. In this way, the beams can be formed with a single set of antenna hardware instead of requiring a multiplicity of antenna hardware, one for each beam. Frequency coding may be implemented by repeatedly applying a Doppler phase shift to each beam, and then using a Doppler filter to separate the beams. Alternatively, a code division multiplexing technique may be implemented by using a CDMA code generator to apply a code to each beam, and then using a CDMA filter to separate the beams.

US Patent:

6788250, Sep 7, 2004

Filed:

Nov 8, 2002

Appl. No.:

10/290985

Inventors:

James M. Howell - Woodstock GA

Assignee:

EMS Technologies, Inc. - Norcross GA

International Classification:

H01Q 322

US Classification:

342372, 342377

Abstract:

A phased array antenna system operative to broadcast multiple beams that each include coded data for specific users located within the coverage area of the corresponding beam. An appropriate receiver then receives and decodes a particular beam to extract the specific data for a corresponding user. Multiple users may be assigned to each beam using frequency division or orthogonal code multiplexing, and the user data may be encoded into the beams using frequency shift key or phase shift key encoding. For each coding technique, the encoded antenna control signals are combined into a total gain and total phase shift control signal, which drives a single phase and gain control device for each antenna element. In addition, a single data modulator generates the coding parameters for the entire communication system.

US Patent:

6950061, Sep 27, 2005

Filed:

Nov 8, 2002

Appl. No.:

10/291443

Inventors:

James M. Howell - Woodstock GA, US
Robert A. Freeman - Norcross GA, US

Assignee:

EMS Technologies, Inc. - Norcross GA

International Classification:

H01Q003/00

US Classification:

342359, 343757

Abstract:

A low-profile antenna system to be mounted to a moving vehicle for receiving signals, such as from a Digital Broadcast Satellite, includes a base for mounting to the surface of the vehicle, a platen mounted to the base for rotation, an azimuth drive motor for rotating the platen, an array of half-cylinder antenna elements mounted to the platen, an elevation drive motor for pivoting the antenna elements individually about their axes to change the elevation at which the antenna elements are pointing, and a cover. The azimuth drive motor and the elevation drive motor together allow the array of antenna elements to be pointed at a satellite over a wide range of vehicle orientations.

US Patent:

7109919, Sep 19, 2006

Filed:

Sep 3, 2004

Appl. No.:

10/934235

Inventors:

James M. Howell - Woodstock GA, US

Assignee:

EMS Technologies, Inc. - Norcross GA

International Classification:

H01Q 3/24
H04Q 7/20
H04Q 7/30

US Classification:

342372, 342377, 4554561

Abstract:

A phased array antenna system operative to broadcast multiple beams that each include coded data for specific users located within the coverage area of the corresponding beam. An appropriate receiver then receives and decodes a particular beam to extract the specific data for a corresponding user. Multiple users may be assigned to each beam using frequency division or orthogonal code multiplexing, and the user data may be encoded into the beams using frequency shift key or phase shift key encoding. For each coding technique, the encoded antenna control signals are combined into a total gain and total phase shift control signal, which drives a single phase and gain control device for each antenna element. In addition, a single data modulator generates the coding parameters for the entire communication system.

US Patent:

20040166801, Aug 26, 2004

Filed:

Nov 12, 2003

Appl. No.:

10/706326

Inventors:

Thomas Sharon - Duluth GA, US
Thomas Taylor - Atlanta GA, US
William Hafner - Alpharetta GA, US
Steven Rigg - Norcross GA, US
James Howell - Woodstock GA, US
Thomas Glynn - Annapolis MD, US
Dennis Kershner - Ellicott City MD, US

Assignee:

EMS Technologies, Inc. - Norcross GA

International Classification:

H04B007/185
H04Q007/20

US Classification:

455/012100, 455/427000

Abstract:

A satellite communications system having ground user terminals, hubs, and a geosynchronous satellite. The satellite generates a network of spot beam coverage areas on the earth. A hub and at least one ground terminal are located in each of at least two spot beams. A first user terminal transmits an uplink signal according to a first signal protocol to the hub through the satellite. A second user terminal receives a downlink signal according to a second signal protocol through the downlink spot beam from the hub through the satellite. The hub may be located in the same spot beam coverage area as the first or the second user terminal or may be located in an altogether different spot beam coverage area. Through selective frequency and/or polarization routing on board the satellite, a hub located within a “parent” beam can communicate with user terminals within the parent beam at a specified frequency and polarization, and can communicate with users in other “dependent” beams on a different frequency and/or polarization. This routing allocates the total available bandwidth between parent and dependent beams. The system enables asynchronous communications between each hub and the satellite to maximize frequency re-use and the overall capacity of the system.

US Patent:

20060017637, Jan 26, 2006

Filed:

Jul 14, 2005

Appl. No.:

11/181377

Inventors:

James Howell - Woodstock GA, US
Anna Howell - Woodstock GA, US

International Classification:

H01Q 19/06

US Classification:

343754000, 343757000

Abstract:

The invention includes a mechanical scanning feed and a spherical lens antenna system. The mechanical feed includes a waveguide, which has a movable wall assembly that contains a guide slot. The moveable wall portion also includes an end wall that is located proximate to the guide slot to prevent leakage of the propagating energy out of the waveguide. The mechanical feed also includes a drive mechanism, which moves the moveable wall assembly along the waveguide in a direction that is parallel to the direction of propagation of the energy. This allows the guide slot to be positioned at any elevation angle to allow a portion of the propagating energy to exit through the guide slot. This in combination with the waveguide being able to be rotated 360 degrees about the spherical lens provides the antenna system with nearly spherical coverage.