Abstract: A system and a method for operating a radar system in a continuous wave mode for communicating information are provided. In one embodiment, the invention relates to a method for operating a radar system, having an antenna including a plurality of active array elements, in a continuous wave mode to communicate information, the method including receiving an instruction to enter the continuous wave mode, loading a plurality of tables, where each table includes information indicative of a primary group of the active array elements to be activated and a secondary group of elements to be deactivated, receiving a communication signal to be transmitted, and providing, repeatedly, the communication signal, for a preselected period of time, to the primary group of elements of each of the plurality of tables.

Abstract: A system and a method for operating a radar system in a continuous wave mode for communicating information are provided. In one embodiment, the invention relates to a method for operating a radar system, having an antenna including a plurality of active array elements, in a continuous wave mode to communicate information, the method including receiving an instruction to enter the continuous wave mode, loading a plurality of tables, where each table includes information indicative of a primary group of the active array elements to be activated and a secondary group of elements to be deactivated, receiving a communication signal to be transmitted, and providing, repeatedly, the communication signal, for a preselected period of time, to the primary group of elements of each of the plurality of tables.

Abstract: A cooperative swarm of unmanned vehicles includes a plurality of unmanned vehicles, each having a location identification system operable to provide location coordinates; a transceiver operable to send and receive location coordinates via omnipresent signals of opportunity, and a guidance system operable to selectively guide the unmanned vehicle towards an identified target and a specified location within an environment. Access to omnipresent signals of opportunity facilitates transmissions indicative of the identified target and/or location between unmanned vehicles in an environment, e.g., an urban environment, where direct line of sight contact is limited. In a related method, at least one omnipresent signal of opportunity is detected within an environment. Location coordinates are transmitted between unmanned vehicles via the detected signal.

Abstract: Provided is a bistatic and multistatic system for detecting and identifying a target in close proximity to an orbiting satellite. An electromagnetic fence is established to surround the satellite, using a ground-based communication uplink from a gateway antenna. A contact or breach of the electromagnetic fence by the target is detected by the satellite, or at other sensor locations, and an exact position, range and ISAR image of the target is calculated using scattered RF energy from the fence. Identification data is transmitted to satellite system monitors, whereby the data is used to decide on a corrective course of action.

Abstract: An optically controlled micro-electromechanical (MEM) switch is described which desirably utilizes photoconductive properties of a semiconductive substrate upon which MEM switches are fabricated. In one embodiment the bias voltage provided for actuation of the switch is altered by illuminating an optoelectric portion of the switch to deactivate the switch. In an alternative embodiment, a photovoltaic device provides voltage to actuate the switch without any bias lines at all. Due to the hysteresis of the electromechanical switching as a function of applied voltage, only modest variation of voltage applied to the switch is necessary to cause the switch to open or close sharply under optical control.

Abstract: An optically controlled micro-electromechanical (MEM) switch is described which desirably utilizes photoconductive properties of a semiconductive substrate upon which MEM switches are fabricated. In one embodiment the bias voltage provided for actuation of the switch is altered by illuminating an optoelectric portion of the switch to deactivate the switch. In an alternative embodiment, a photovoltaic device provides voltage to actuate the switch without any bias lines at all. Due to the hysteresis of the electromechanical switching as a function of applied voltage, only modest variation of voltage applied to the switch is necessary to cause the switch to open or close sharply under optical control.

Abstract: An optically controlled micro-electromechanical (MEM) switch is described which desirably utilizes photoconductive properties of a semiconductive substrate upon which MEM switches are fabricated. In one embodiment the bias voltage provided for actuation of the switch is altered by illuminating an optoelectric portion of the switch to deactuate the switch. In an alternative embodiment, a photovoltaic device provides voltage to actuate the switcdh without any bias lines at all. Due to the hysteresis of the electromechanical switching as a function of applied voltage, only modest variation of voltage applied to the switch is necessary to cause the switch to open or close sharply under optical control.

Abstract: A method and apparatus for comparing a force to a signal, or comparing two signals, through mechanical movement of capacitive plates in a transducer. The transducer plates are separated by d, which in one embodiment is preferably a linear function of a pressure or force F. In that embodiment, application of a signal i(t+&tgr;) to the plates will cause a voltage representing a correlation between F and i to appear between the plates. In another embodiment, instead of an external mechanical force or pressure, an electrical signal V related to a signal S may drive the transducer plates to achieve a voltage indicating a correlation between S and the signal input i(t+&tgr;). Transducers to practice the invention may be microelectromechanical devices fabricated using integrated circuit techniques to permit small size and low cost.

Abstract: A front end module (10, 30) for a low weight, low power communications system. The front end module (10) utilizes RF microelectromechanical (MEM) switches (16, 18, 20, 110, 112, 156) for dynamic reconfiguration capability. Components (12, 14, 22, 24, 26, 28) are shared for both the transmit and receive modes, thereby reducing the number of components required by the system (10, 30).

Abstract: An optically controlled micro-electromechanical (MEM) switch is described which desirably utilizes photoconductive properties of a semiconductive substrate upon which MEM switches are fabricated. In one embodiment the bias voltage provided for actuation of the switch is altered by illuminating an optoelectric portion of the switch to deactuate the switch. In an alternative embodiment, a photovoltaic device provides voltage to actuate the switch without any bias lines at all. Due to the hysteresis of the electromechanical switching as a function of applied voltage, only modest variation of voltage applied to the switch is necessary to cause the switch to open or close sharply under optical control.

Abstract: A method and system for transmitting, and a signal comprising multiple frequency bands from a single slot antenna are disclosed. The system comprises a slot antenna and a micro-electro-mechanical (MEM) switch, coupled to the slot antenna. The MEM switch is opened and closed, thereby changing the resonant frequency of the slot antenna. The slot antenna transmits a first frequency when the MEM switch is open and a second frequency when the MEM switch is closed. The method for transmitting a first frequency and a second frequency from a slot antenna comprises the steps of transmitting the first frequency from the slot antenna, closing a micro-electro-mechanical (MEM) switch coupled across the slot antenna, therein changing the resonant frequency of the slot antenna, and transmitting the second frequency from the slot antenna after the MEM switch is closed.

Abstract: An optically controlled micro-electromechanical (MEM) switch is described which desirably utilizes photoconductive properties of a semiconductive substrate upon which MEM switches are fabricated. In one embodiment the bias voltage provided for actuation of the switch is altered by illuminating an optoelectric portion of the switch to deactivate the switch. In an alternative embodiment, a photovoltaic device provides voltage to actuate the switch without any bias lines at all. Due to the hysteresis of the electromechanical switching as a function of applied voltage, only modest variation of voltage applied to the switch is necessary to cause the switch to open or close sharply under optical control.

Abstract: A method and system for transmitting, and a signal comprising multiple frequency bands from a single slot antenna are disclosed. The system comprises a slot antenna and a micro-electro-mechanical (MEM) switch, coupled to the slot antenna. The MEM switch is opened and closed, thereby changing the resonant frequency of the slot antenna. The slot antenna transmits a first frequency when the MEM switch is open and a second frequency when the MEM switch is closed. The method for transmitting a first frequency and a second frequency from a slot antenna comprises the steps of transmitting the first frequency from the slot antenna, closing a micro-electro-mechanical (MEM) switch coupled across the slot antenna, therein changing the resonant frequency of the slot antenna, and transmitting the second frequency from the slot antenna after the MEM switch is closed.

Abstract: Mixing and modulating methods are described for nonlinear optical amplifiers (30) which can generate intermodulation products of radio-frequency signals in an optical carrier signal (26) without the penalty of an optical conversion loss and without the need for radio-frequency mixers, electro-optic modulators and expensive polarization-maintaining optical fibers. The radio-frequency signals can be applied to either a bias port (36) or an optical input port (32) of the optical amplifier and are used to upconvert and downconvert signals in phased-array antenna and remote antenna embodiments of the invention.

Abstract: A phased array radar system employs programmable microelectromechanical (MEM) switches and transmission lines to provide true time delays or phase shifts in order to steer the array beam. The array includes an excitation signal source, a power division network for dividing the excitation signal into a plurality of excitation signal components, a plurality of programmable time delay/phase shift circuits including the transmission lines and MEM switches, and a plurality of radiating elements. An adaptive controller provides the control signals to set the MEM switches and select the time delay/phase shift through each time delay/phase shift circuit, thereby steering the array beam to a desired direction.

Abstract: A diamond matrix metallic mesh suppresses RF energy, and particularly side lobe energy, in a phased array antenna, while passing main beam energy. The metal mesh emulates the structure of the bond segments joining the carbon atoms in a diamond structure. The wire diamond lattice structure is placed above an array of radiating elements to absorb side lobe energy. The wire lattice structure is fabricated through use of complementary forms which compress a wire into a required unit shape. Many unit shaped wires are placed in a form which hold the wires in the proper position. Other unit shaped wires are rotated 90 degrees and attached in place to the held wires. Additional unit shaped wires are added to form the basic interlocking cube structure of the diamond lattice.

Abstract: A diamond matrix metallic mesh suppresses RF energy, and particularly side lobe energy, in a phased array antenna, while passing main beam energy. The metal mesh emulates the structure of the bond segments joining the carbon atoms in a diamond structure. The wire diamond lattice structure is placed above an array of radiating elements to absorb side lobe energy. The wire lattice structure is fabricated through use of complementary forms which compress a wire into a required unit shape. Many unit shaped wires are placed in a form which hold the wires in the proper position. Other unit shaped wires are rotated 90 degrees and attached in place to the held wires. Additional unit shaped wires are added to form the basic interlocking cube structure of the diamond lattice.

Abstract: A diamond lattice structure is employed as a ground plane in an array antenna system. The ground plane structure reflects incident energy radiated by the antenna radiating elements. The structure is fabricated from a layer of dielectric photonic band gap material in which a periodic void structure is defined. The void diameter is selected to maximize the void volume within the structure. Methods of constructing the ground plane are described.

Abstract: A broadband antenna system utilizes multiple photonic bandgap crystals to achieve nearly 100 percent power efficiency over a larger range of frequencies than prior antenna systems. Multiple custom tailored photonic bandgap crystals form a substrate for the antenna system. Each of the crystals is designed to cover a specific range of frequencies. The multiple crystals are attached together to form a photonic bandgap substrate whose bandwidth varies as a function of location on the substrate. A broadband antenna that can cover a wide frequency range, and whose active region shifts to different portions of the antenna as a function of frequency, is formed on the substrate such that the active region of the antenna is always on a crystal that has a corresponding operating bandwidth. The photonic bandgap crystals provide a nearly 100 percent efficient reflector for radiation emitted into the substrate that would otherwise be trapped or dissipated therein.

Abstract: An antenna system includes a set of symmetrically located center-fed and segmented dipole antennas embedded on top of a frequency selective photonic bandgap crystal. A two-dimensional array of microelectromechanical (MEM) transmission line switches is incorporated into the dipole antennas to connect the segments thereof. An MEM switch is located at the intersection between any two adjacent segments of the antenna arm. The segments can be connected (disconnected) by operating the switch in the closed (open) position. Appropriate manipulation or programming of the MEM switches will change the radiation pattern, scanning properties and resonance frequency of the antenna array. In addition, an MEM switch is inserted into the crystal to occupy a lattice site in the 3-dimensional crystal lattice.