Roger E Roberts

US Patent:

53029585, Apr 12, 1994

Filed:

Aug 14, 1992

Appl. No.:

7/929529

Inventors:

Roger G. Roberts - Auburn GA
Paul R. Cox - Duluth GA

Assignee:

EMS Technologies, Inc. - Norcross GA

International Classification:

G01S 1300

US Classification:

342157

Abstract:

A low loss, fast switching, electronically tunable filter circuit which is microstrip compatible is obtained through the use of a resonant ring structure having two couplers, a low noise amplifier and a variable phase shifter. The tunable filter may advantageously be used in the receive channel of a transmit/receive module for phased arrays wherein the resonant frequency of the ring can be tuned anywhere in the operating frequency range so as to increase the dynamic range of the receiver.

US Patent:

51701383, Dec 8, 1992

Filed:

Mar 15, 1991

Appl. No.:

7/669959

Inventors:

Roger G. Roberts - Auburn GA
Thomas E. Sharon - Alpharetta GA

Assignee:

Electromagnetic Sciences, Inc. - Norcross GA

International Classification:

H01P 1195

US Classification:

333 241

Abstract:

A miniaturized waveguide mode ferrite RF phase shifter is efficiently transitioned to a matched impedance microstrip transmission line mode at either end to result in an ultra small, efficient and lightweight essentially "planar" phase shifter device having a single ferrimagnetic toroid.

US Patent:

51443198, Sep 1, 1992

Filed:

Mar 14, 1991

Appl. No.:

7/669883

Inventors:

Roger G. Roberts - Auburn GA

Assignee:

Electromagnetic Sciences, Inc. - Norcross GA

International Classification:

H01Q 324
H01P 1185
H01P 1195

US Classification:

342372

Abstract:

An RF phase shifter combines a non-reciprocal ferrite 180. degree. stage with one or more reciprocal diode phase shifting stages to produce an essentially planar phase shifter that is ultra small, efficient and lightweight. Such phase shifter elements may be used in phased arrays to produce an array offering major improvements over existing planar substrate all diode phase shifters while maintaining the phase gradient between array elements and without switching the ferrite shifter between the transmit and receive modes.

US Patent:

59559985, Sep 21, 1999

Filed:

Jan 5, 1996

Appl. No.:

8/583707

Inventors:

Roger G. Roberts - Auburn GA
Wyman L. Williams - Duluth GA
Jeff M. Alexander - Clarkston GA

Assignee:

EMS Technologies, Inc. - Norcross GA

International Classification:

H01Q 1310

US Classification:

343768

Abstract:

A ferrite scanning line source is formed of a ferrite toroid and one or more dielectric slabs mounted to a side of the toroid. A signal propagating through the waveguide is phase shifted by the magnetization of the toroid. The further down the toroid the signal propagates the greater the phase shift that is applied to the signal. Radiators or coupling ports are formed by slots cut in a wall of the waveguide. The phase of the signal radiating from each slot in the line source is shifted from the signals emanating from the preceding and following slot in the line source. By properly locating the slots along the line source, a composite beam formed by the energy radiating from each slot may be titled (scanned) to a desired direction. In addition, the amount of phase shift applied to the signal by the waveguide depends on the magnetic state of the phase shifter. By changing the magnetic state of the phase shifter, by using a latch wire, the direction of the beam emanating from the line source can be scanned, such as by. +-. 20. degree.

US Patent:

51290995, Jul 7, 1992

Filed:

Mar 30, 1989

Appl. No.:

7/330638

Inventors:

Roger G. Roberts - Auburn GA

Assignee:

Electromagnetic Sciences, Inc. - Norcross GA

International Classification:

H04B 148
H01P 132

US Classification:

455 81

Abstract:

A reciprocal transceiver to radiator coupling circuit uses both microstrip and waveguide modes of RF signal transmission (including a pair of nonreciprocal hybrid mode phase shifters) to gain size and weight advantages useful in feeding large scale phase arrays. At the same time, the radar cross section of such array apertures is reduced by arranging separate nonreciprocal receive and transmit branches of the circuit to route spurious intra-circuit reflections of incoming RF signals to a matched termination.

US Patent:

50756486, Dec 24, 1991

Filed:

Mar 30, 1989

Appl. No.:

7/330617

Inventors:

Roger G. Roberts - Auburn GA
Jeff M. Alexander - Clarkston GA
James P. Montgomery - Roswell GA

Assignee:

Electromagnetic Sciences, Inc. - Norcross GA

International Classification:

H01P 504
H01P 5107
H01P 512

US Classification:

333128

Abstract:

A miniaturized waveguide mode ferrite RF phase shifter is efficiently transitioned to a matched impedance microstrip transmission line mode at either end to result in an ultra small, efficient and lightweight essentially "planar" phase shifter device having wide application in the microwave industry.

US Patent:

53049993, Apr 19, 1994

Filed:

Nov 20, 1991

Appl. No.:

7/795026

Inventors:

Roger G. Roberts - Auburn GA
Thomas E. Sharon - Alpharetta GA

Assignee:

Electromagnetic Sciences, Inc. - Norcross GA

International Classification:

H01Q 336
H01P 1161
H01P 516
H01P 118

US Classification:

343778

Abstract:

A 90. degree. coupling circuit cascaded with a pair of hybrid mode latchable phase shifters provides polarization agility for an RF radiator module of the type typically used in a phased array. For example, such radiator modules typically may utilize an active microwave integrated circuit (MIC), a monolithic microwave integrated circuit (MMIC) or a passive reciprocal hybrid mode element (RHYME) circuit. These circuits are arranged to provide duplex RF transmit/receive functions with controllable phase shifts at each radiator site in a phased array. By appropriately setting the two controllable phase shifters to different combinations of phase shifts (e. g. , 0. degree. and/or 90. degree. ) to a dual orthogonal mode radiator, different spatial polarizations for RF radiator transmit/receive functions can be defined. The radiator itself may include a square or circular waveguide including, in some cases, a reciprocal dielectric quarter-wave plate and a non-reciprocal ferrite quarter-wave plate.

US Patent:

44450982, Apr 24, 1984

Filed:

Feb 19, 1982

Appl. No.:

6/350418

Inventors:

Thomas E. Sharon - Decatur GA
Roger G. Roberts - Auburn GA

Assignee:

Electromagnetic Sciences, Inc. - Norcross GA

International Classification:

H01P 1397
H01P 111
H01P 1195

US Classification:

333 11

Abstract:

The present invention is for an apparatus and method of fast-switching a dual-toroid microwave ferrite phase shifter. A first circuit is provided for controllably switching the ferrite in one of the toroids between a saturated and partially saturated states. A second conduit is provided for controllably switching the ferrite in the other of the toroids between a saturated and partially saturated states. A control circuit is provided for controlling the first and second circuits such that the ferrite in at least one of the toroids is maintained in the saturated state at any given time such that any desired phase shift may be achieved with only one switching operation for each toroid. The present invention provides new reference states such that there are two reciprocal phase states for any given phase state such that a reciprocal phase state may always be achieved with only one switching operation for each toroid.