Bae Systems Information and Electronic Systems Integration Inc.

Bae Systems Information and Electronics Systems Integration Inc.

Sanders Associates Limited

Roland A Gilbert

John T Apostolos

Paul A Zank

Eldon M Sutphin

Court E Rossman

Tadd C Kippeny

Zane Lo

Paul Gili

Michael J Bowers, Ii

Don A Harris

David P Charette

Darrel F Sedivec

Michael D Blazej

John A Windyka

David H Herlihy

Jesse L Butler

A system and method for detecting at least one compound in a material under test (MUT) is presented. The system includes a Nuclear Quadrupole Resonance (NQR) frequency generator that generates an NQR frequency (f) and propagates the ffrequency toward the MUT. A microwave frequency generator generates a microwave frequency (f) and propagates the ffrequency toward the MUT. A RF output probe detects radio frequency (RF) emissions returned from the MUT. A detector detects the at least one compound based, at least in part, on whether the RF emissions returned from the MUT include any frequencies corresponding to f+/&#x2212;(n&#xd7;f), where n is an integer of 2 or greater. In the preferred embodiment, n=2.

Detection using microwave assisted NQR

A system and method for detecting at least one material under test (MUT) is presented. A Nuclear Quadrupole Resonance (NQR) measurement system includes a waveform generator configured to generate a continuous wave (CW) input signal comprising one or more frequencies. An RF shielded chamber receives the at least one MUT that is carried by a person walking through the chamber. A probe within the chamber illuminates the MUT with the CW signal and simultaneously receives possible NQR emissions from the at least one MUT. A bridge circuit is utilized to cancel the strong excitation CW signal from the generator which would otherwise mask the weak NQR emissions from the MUT that are received and detected by the measurement system. A detector can then detect the MUT based, at least in part, on the resonance signal.

Nuclear quadrupole resonance system

A method and apparatus is provided for avoiding pattern blockage due to scatter from an object in which an artificial surface directs the energy from the antenna prior to arriving at a blocking structure such that either the wave fronts of the energy are linear when they arrive at the blocking structure or the phase of the energy incident on the object is adjusted such that the energy reflected from the object is in phase with energy directly from the antenna radiating elsewhere in the far field pattern, or both.

Method and apparatus for avoiding pattern blockage due to scatter

A system and method for distributing the power of an electromagnetic signal is presented. In one embodiment, a power distribution cavity includes, a planar cavity, input ports and output ports. The planar cavity is formed with a metallic sheet in the shape of a star pattern with a plurality of elongated star arms extending from a round center portion of the metallic sheet. The input ports are attached to the round center portion of the metallic sheet for receiving an input signal. The signals entering the cavity from the input ports creating independent resonant modes within the cavity that combine producing a tapered aperture distribution of signals at the output ports. The output ports are attached near to the outward ends of the elongated star arms. The planar cavity is thus configured to propagate electromagnetic fields at the output ports that were excited within the cavity by the input ports.

Planar tri-mode cavity

A method for mounting multiple small RFID chips onto larger antenna. The chips are mechanically aligned with an interdigitated gap at the feed point of the antenna by electrostatic or magnetic techniques. In an alternate embodiment RF field coupling between the chips and the antenna is employed.

Methods for coupling an RFID chip to an antenna

An RF-actuated microelectromechanical systems (MEMS) switch for use with switchable RF structures such as antennas and reflectors is disclosed. An antenna within each MEMS switch module is coupled to a circuit that provides a trigger voltage based on an RF control signal received at the antenna. The trigger voltage output of the circuit is used as the control the MEMS switch. This allows arrays of MEMS switch modules to be actuated by remotely generated radio frequency signals thus alleviating the need for running metallic conductors or optical fibers to each MEMS switch. Frequency response characteristics, phasing, reflectivity, and directionality characteristics may be altered in real-time.

RF-actuated MEMS switching element

A miniature broadband monopole antenna design configured with integrated band-selecting filtering is disclosed. The antenna is electrically folded, and includes top and bottom monopole sections, with a meanderline to provide an inductive load between the two sections. The overall antenna structure can be embedded in a relatively small, RF transparent, composite structure (e.g., such as the fin of a guided munition), and has minimal impact on aerodynamics (low drag). The top, bottom, and meanderline elements of the antenna operate together to collectively provide multi-band operation (e.g., 30 MHz to 3 GHz).

Miniature multi-band, electrically folded, monopole antenna

A gapless Vivaldi notch/meander line antenna is provided having a top plate with a Vivaldi notch, a cavity and a rearwardly-extending notch, with the top plate having integral side plates and a meander line bridging the rearwardly-extending notch at its distal end.

Gapless concatenated Vivaldi notch/meander line loaded antennas

The present invention features an RF-actuated microelectromechanical systems (MEMS) switch for use with switchable RF structures such as antennas. An antenna within each MEMS switch module is coupled to a tuned circuit and a detector. The DC voltage output of the detector is used as the control input to the MEMS switch. This allows arrays of MEMS switch modules to be actuated by remotely generated radio frequency signals thus alleviating the need for running metallic conductors or optical fibers to each MEMS switch. The MEMS switch is particularly suited for use in conjunction with both passive and active antenna elements to allow reconfiguration of antenna or other RF structures. Frequency response characteristics, phasing, and directionality characteristics may be altered easily.

Method and apparatus for using RF-activated MEMS switching element

Combined Vivaldi notch and meander line loaded antennas are concatenated in an array to provide an ultra wideband antenna having a decreased low frequency cut-off due to the concatenation. In the concatenation process, plates of adjacent antennas are shared so that one plate is used for both of the adjacent antennas. In a preferred embodiment, the side plates and the top and bottom plates are identically configured.

Concatenated Vivaldi notch/meander line loaded antennas

The present invention provides a broadband RF absorptive structure based on a classic Salisbury screen. Closely-spaced frequency selective surface reflective layers interact with a ground plane to reflect coherent signals at 377&OHgr; into a spacecloth front layer. The frequency response of the absorptive structure is relatively flat across an octave (i.e. a 2:1 frequency ratio) bandwidth. The overall thickness of the inventive structure is less than &lgr;/4 thickness of the interactions of the FSS layers and the ground plane.

Thin, broadband salisbury screen absorber

The present invention provides a low-cost, frequency-tunable, steerable, reflector array capable of simulating the electromagnetic effects of a parabolic or similarly-shaped reflector on a planar or conformal surface. Simple scatterers such as short circuited dipoles, disposed on a geometrically planar or conformal substrate, are configured from a series of scatterer sub-elements, electrically connected serially to one another by MEMS switches. These connected scatterer sub-elements form a reflective array disposed above a ground plane on the substrate. By properly controlling the length and spacing of the activated dipole elements, it is possible to simulate the equiphase reflection profile of a horn feed or sub-reflector feed of a parabolic or similar reflector. In addition, the array may be steered by selectively controlling the scatterer configurations.

Dipole tunable reconfigurable reflector array

The present invention provides a low-cost, steerable antenna formed with a dielectric medium separating a pair of conductive plates and a centrally located signal feed. Switches selectively interconnect the conductive plates through the dielectric medium in patterns, which determine the direction of operation of the antenna. The directionality of the antenna may be fixed or rapidly changed, depending upon the application.

Metamorphic parallel plate antenna

The present invention provides a programmable image antenna formed on the face plate of a cathode ray tube (CRT) or on another substrate. The inner CRT face is coated with a silicon semiconductor material replacing conventional phosphors utilized in CRTs for generating visual images. An electron beam impinging upon the silicon-coated CRT face plate creates conductive areas during liberation of minority carriers, in the form of electron-hole pairs. Antenna elements having a virtually unlimited variety of shapes and/or sizes can be formed on the CRT face.

Programmable image antenna

The present invention provides a reconfigurable diplexer which is well suited for use with mulitple element antenna arrays. The diplexer includes a common, slot-line transmission line adapted to carry electromagnetic signals; a pair a separate slot-line transmission lines coupled to the common transmission line; each separate slot-line transmission line having an individual filter coupled thereto, wherein each filter is adapted to selectively give its respective separate slot-line transmission line a characteristic impedance dependent upon predetermined frequencies of the electromagnetic signals; and a separate slot-line balun associated with each separate slot-line transmission line and adapted for coupling signals to and/or from its respective separate slot-line transmission line. The diplexer may be configured to operate in several different bands such as the INTELSAT frequencies (7.2-8.4 GHz) or DSCS frequencies (11.7-14.5 GHz).

Growing community of inventors

Milford, NH, United States of America

Roland A Gilbert