Electromagnetic Sciences, Inc.

Ems Technologies, Inc.

Roger G Roberts

Thomas E Sharon

Jeff M Alexander

James P Montgomery

Wyman L Williams

Paul R Cox

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.. Phased array antenna systems are formed of groups of radiating elevation line sources that are fed signals by a group of azimuth line sources coupled by microstrips to the elevation line sources.

Electronically scanned ferrite line source

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. If a square waveguide is utilized, then 0.degree., 90.degree. hybrid mode latchable phase shifters may be arranged on either side of a common ground plane with direct waveguide coupling into a septum polarizer waveguide section of the radiator element. A 90.degree. Lange hybrid coupler also may be used by itself in conjunction with an electrically rotatable ferrite quarter-wave plate radiating element to achieve a certain degree of polarization agility.

Polarization agility in an RF radiator module for use in a phased array

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.

Low loss, fast switching, tunable filter circuit

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.

Single toroid hybrid mode RF phase shifter

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.

Planar substrate ferrite/diode phase shifter for phased array

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.

Reciprocal hybrid mode RF circuit for coupling RF transceiver to an RF

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.

Hybrid mode RF phase shifter and variable power divider using the same

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.

Growing community of inventors

Auburn, GA, United States of America

Roger G Roberts