Abstract: Provided is an antenna transceiver system for transmitting and receiving voice, digital data, radar and IR signals, and for processing received signals for use by an operator. The system includes an antenna array having a plurality of radiating elements, each element connected to a transmit/receive (“T/R”) module. Each T/R module includes phase shifters, as well as a phase conjugation module for transmitting a return signal to a location along a beam path of an incoming signal. Transmission of the return signal does not require knowledge of the location of either the signal source or the antenna transceiver system. The antenna transceiver system is disposed on a plurality of vertically aligned planes integrated into a compact unit. The units can be embedded in headgear of a user, allowing for hands-free operation of the system. Alternatively, the antenna transceiver system can be integrated into a vehicle, man-transportable backpack, or other designated platforms.

Abstract: A phased array antenna adapted to be mounted in a helmet. In the illustrative embodiment, the antenna comprises a substrate and an array of radiating elements disposed on said substrate, each of the elements including a-resonant cavity and a mechanism for feeding the cavity with an electromagnetic signal., The cavity is formed in a multi-layer structure between a ground plane and a layer of metallization. A radiating slot or slots are provided in the layer of metallization. A first layer of dielectric material is disposed within the cavity. The feed mechanism is a microstrip feed disposed in the first layer of dielectric material parallel to a plane of a portion of the substrate over which an associated element is disposed. A layer of foam is disposed between the layer of dielectric material and the ground plane. Second and third parallel layers of dielectric material are included in each element. The second layer is disposed adjacent to the ground plane.

Abstract: A system for scanning an antenna array of the present invention. The system includes a first mechanism for modulating a desired signal on an optical carrier signal. The first mechanism includes a frequency-tunable optical oscillator with a phase shifter for changing an output frequency of the optical oscillator. A second mechanism employs the optical carrier signal to derive signals having predetermined phase relationships. A third mechanism receives the feed signals and radiates corresponding transmit signals in response thereto to the antenna array to steer the array. In more specific embodiment, the desired signal is a Radio Frequency (RF) signal, and the phase shifter is an electrically controlled optical RF phase shifter. The optical carrier signal includes a first optical carrier signal and a second optical carrier signal.

Abstract: A phased array antenna adapted to be mounted in a helmet. In the illustrative embodiment, the antenna comprises a substrate and an array of radiating elements disposed on said substrate, each of the elements including a-resonant cavity and a mechanism for feeding the cavity with an electromagnetic signal., The cavity is formed in a multi-layer structure between a ground plane and a layer of metallization. A radiating slot or slots are provided in the layer of metallization. A first layer of dielectric material is disposed within the cavity. The feed mechanism is a microstrip feed disposed in the first layer of dielectric material parallel to a plane of a portion of the substrate over which an associated element is disposed. A layer of foam is disposed between the layer of dielectric material and the ground plane. Second and third parallel layers of dielectric material are included in each element. The second layer is disposed adjacent to the ground plane.

Abstract: A system for scanning an antenna array of the present invention. The system includes a first mechanism for modulating a desired signal on an optical carrier signal. The first mechanism includes a frequency-tunable optical oscillator with a phase shifter for changing an output frequency of the optical oscillator. A second mechanism employs the optical carrier signal to derive signals having predetermined phase relationships. A third mechanism receives the feed signals and radiates corresponding transmit signals in response thereto to the antenna array to steer the array. In more specific embodiment, the desired signal is a Radio Frequency (RF) signal, and the phase shifter is an electrically controlled optical RF phase shifter. The optical carrier signal includes a first optical carrier signal and a second optical carrier signal.

Abstract: A system for generating a simulated radar return signal. The novel system includes a processor adapted to receive target and waveform parameters and in accordance therewith generate a composite digital signal, and a digital to analog converter adapted to convert the digital signal to an analog signal. The system also includes an upconverter adapted to convert the analog signal to radio frequency. The processor calculates time-domain digital data samples representing a composite radar return waveform based on the target and waveform parameters. These data samples are output at each time interval that the digital to analog converter samples data. The composite waveform can include returns from a large number of targets and from targets embedded in clutter. The system can also be adapted to test a radar system having multiple antenna ports by replicating the basic design for each port.

Abstract: A recirculating delay line that includes an optical delay circuit generates repetitions of an input signal waveform that is of limited time duration.

Abstract: A millimeter wave (MMW) antenna array includes a continuous transverse stub (CTS) radiating aperture comprising a set of spaced continuous transverse stubs, each having a longitudinal extent. A series feed system is coupled to an excitation source for exciting the stubs with MMW electromagnetic energy having a linear phase progression along the longitudinal extent of the stubs to produce an array beam which can be scanned over a beam scan range by changing the excitation frequency.

Abstract: A the system for scanning an antenna array (26) adapted for use with active radar arrays. A first mechanism (14, 18, 20, 24) generates an optical signal oscillating at a predetermined frequency. A second mechanism (32, 34) employs the optical signal to derive feed signals, which have predetermined phase relationships. A third mechanism (22) receives the feed signals and radiates corresponding transmit signals in response thereto to the antenna array (26) to steer the antenna array (26) in accordance with the predetermined phase relationships. In a specific embodiment, the transmit signals are microwave frequency signals. The first mechanism (14, 18, 20, 24) includes a first optical oscillator (18) and a second optical oscillator (20) that feed a first optical manifold (32) and a second optical manifold (34), respectively, of the second mechanism (32, 34).

Abstract: A recirculating delay line that includes an optical delay circuit generates repetitions of an input signal waveform that is of limited time duration.

Abstract: A system and method for automatically generating a return beam in the direction of a received beam. The inventive system (10) includes a phased array antenna (12) for receiving a radio frequency signal having a first wavefront from a first direction. In response to this signal, the invention (10) provides a second signal having a second wavefront. The second signal is a phase conjugate of the first signal and is transmitted in a reverse direction relative to the direction of the first signal. In the illustrative embodiment, the invention includes a plurality of phase conjugators each of which are disposed in a transmit/receive module and coupled to an associated radiating element. Each of the phase conjugators includes a mixer (60) having the input signal as a first input thereto. The input signal has a first frequency and a first phase.

Abstract: The invention is an optoelectronic (OE) crossbar switch (10) for both digital and analog signals, used either separately or combined, whose functions are reconfigurable and distributed. The invention allows multiple senders to be connected with multiple receivers simultaneously. The invention uses optical filters for wavelength division multiplexing and demultiplexing (WDM and WDD). A single fiber module input/output port carries multiple bi-directional signals that are optically filtered out in the module using WDM/WDD filters (12) at each sender/receiver and then selected after optical filtering using photodiode detectors (15) as detectors and switches. Laser transmitters (14), photodiode detectors (15), and smart electronics (18) are used to implement the crossbar switch functions.

Abstract: A system and technique for phased array antenna beam steering for transmitting and receiving without sending the waveform through an actual (physical) time delay when a time varying frequency is used as the waveform. The inventive system is adapted for use with an antenna having an array of radiating elements and includes a plurality of signal sources. Each source is adapted to provide a signal having a predetermined frequency offset signal for an associated radiating element or set of radiating elements. For transmit a plurality of first mixers is provided. Each of the first mixers is coupled to receive an excitation signal as a first input and the output from a respective one of the sources as a second input. The output of each mixer is coupled to a respective subset of the antenna radiating elements. In effect, each of the sources provides a virtual time delay.

Abstract: A system and technique for phased array antenna beam steering for transmitting and receiving without sending the waveform through an actual (physical) time delay when a time varying frequency is used as the waveform. The inventive system is adapted for use with an antenna having an array of radiating elements and includes a plurality of signal sources. Each source is adapted to provide a signal having a predetermined frequency offset signal for an associated radiating element or set of radiating elements. For transmit a plurality of first mixers is provided. Each of the first mixers is coupled to receive an excitation signal as a first input and the output from a respective one of the sources as a second input. The output of each mixer is coupled to a respective subset of the antenna radiating elements. In effect, each of the sources provides a virtual time delay.

Abstract: The invention is an optoelectronic (OE) crossbar switch (10) for both digital and analog signals, used either separately or combined, whose functions are reconfigurable and distributed. The invention allows multiple senders to be connected with multiple receivers simultaneously. The invention uses optical filters for wavelength division multiplexing and demultiplexing (WDM and WDD). A single fiber module input/output port carries multiple bi-directional signals that are optically filtered out in the module using WDM/WDD filters (12) at each sender/receiver and then selected after optical filtering using photodiode detectors (15) as detectors and switches. Laser transmitters (14), photodiode detectors (15), and smart electronics (18) are used to implement the crossbar switch functions.

Abstract: A substantially lossless transmissive link, such as an RF fiber optic link, that selectively employs a number of techniques to improve various link parameters. The link may be structured to comprise a high power light source, such as a laser, that provides light output having a high level of optical power. A feedback circuit may be disposed around the light source that reduces relative-intensity-noise levels produced by the light source at low frequencies. A modulator is provided that modulates the light output of the light source. Preferably, a dual output modulator may be used to provide two modulated optical signals whose respective RF modulation is “effectively” 180 degrees out of phase. An optical fiber that transmits the modulated optical signal(s). A photodetector without a load resistor directly on its output that is operable at the high level of optical power, receives the modulated light and recovers the RF signal.

Abstract: Fiber optic delay lines in the form of a modified corporate feed having progressive phase delays and a corporate feed having equal phase delays are used to couple RF modulated light signals to detecting, mixing, amplifying and radiating devices of an active array radar. Different RF signals may be sent over the same fiber delay lines using different light colors (or wavelengths) so that the RF modulated signals in the fiber delay lines do not interact with each other. The RF signals can be put on and taken out of the fiber lines using wavelength division multiplexers, for example. This provides an array with a single optical manifold that allows simultaneous full aperture operation at multiple frequencies and/or beams over a wide operating frequency range.

Abstract: A noise measurement test system 10' for making phase noise and amplitude noise measurements of microwave signals derived from a continuous wave RF source. The system 10' comprises an RF input for receiving an applied RF noise signal and an RF coupler 11 coupled to the RF input for splitting the applied RF noise signal into first and second paths 18a, 18b. A mixer 15 that comprises a synchronous phase detector 15 is coupled to receive signals from the first and second paths 18a, 18b, respectively, and which outputs demodulated phase noise. The first path 18a comprises a variable attenuator 14 and a variable phase shifter 13 coupled between the coupler 11 and the first input of the mixer 15 for providing a reference signal input to the synchronous detector 15. The second path 18b comprises a delay line and an adjustable RF carrier nulling circuit 30 coupled between the coupler 11 and the mixer 15.

Abstract: An electronic device operating in the microwave frequency range having components disposed in a plurality of planes, wherein the planes are stacked vertically. The electronic device is a T/R module or element forming a part of a subarray used in an active array radar. The T/R module or element comprises a transmit chip, a receive chip, low noise amplifiers, a phase shifter, an attenuator, switches, dc power supply, interconnects that interconnect the foregoing components and logic circuits to control the foregoing components. The components when stacked in a 3-D package are disposed behind a radiator or antenna, which transmits and receives the microwave signals. Behind the T/R module or element is a manifold which provides input and output to and from the T/R module or element. The microwave chips of the T/R module are monolithic microwave integrated circuit chips and control logic, which are disposed in an aluminum nitride substrate and coated with a conformal hermetic coating.

Abstract: A calibration and diagnostic system and method for evaluating the performance of a wide band array utilizing a true-time-delay beamforming network. A short pulse typically on the order of a 2 nanoseconds is synthesized by transmission of a large number of discrete, equally spaced frequencies over the bandwidth over a short period of time, during which the system response (amplitude and phase) is measured and stored in a computer. The collected data is then transformed into the time domain to demonstrate the range resolution of the system. By signal injection with a built-in calibration system, the setting of each programmable delay line of the array can be calibrated. A fiber-optic test set is used as a transponder in the far field to perform complete end-to-end tests of the array system.