Abstract: A method and system use the mutual coupling property of multiple antenna elements for measuring differences in propagation time among various signal paths involving antenna elements in a radio frequency transmit/receive system. The method and system alleviate the need for external test equipment by using the same hardware used in standard operation of the transmit/receive system for performing propagation time measurement through the generation, mutual coupling, and acquisition of a specially selected reference signal. In an embodiment involving calibration of various signal paths to realize matched propagation times, the signal energy returned through these various paths during standard system operation arrives for acquisition more closely coincident in time, increasing the instantaneous bandwidth of the system.

Abstract: A quasi-switched, multi-band, high-power amplifier includes an input matching network, a low band path, a high band path, and an output matching network. The input matching network includes a single input port that is configured to receive an input signal. The input signal includes at least one tone within a specified frequency band. The low band path is configured, when the specified frequency band is a low frequency band, to amplify the input signal to generate a low band amplified signal. The high band path is configured, when the specified frequency band is a high frequency band, to amplify the input signal to generate a high band amplified signal. The output matching network includes a single output port and is configured to filter at least one of the low band amplified signal and the high band amplified signal into a load through the single output port.

Abstract: A method and system use the mutual coupling property of multiple antenna elements for measuring differences in propagation time among various signal paths involving antenna elements in a radio frequency transmit/receive system. The method and system alleviate the need for external test equipment by using the same hardware used in standard operation of the transmit/receive system for performing propagation time measurement through the generation, mutual coupling, and acquisition of a specially selected reference signal. In an embodiment involving calibration of various signal paths to realize matched propagation times, the signal energy returned through these various paths during standard system operation arrives for acquisition more closely coincident in time, increasing the instantaneous bandwidth of the system.

Abstract: A quasi-switched, multi-band, high-power amplifier includes an input matching network, a low band path, a high band path, and an output matching network. The input matching network includes a single input port that is configured to receive an input signal. The input signal includes at least one tone within a specified frequency band. The low band path is configured, when the specified frequency band is a low frequency band, to amplify the input signal to generate a low band amplified signal. The high band path is configured, when the specified frequency band is a high frequency band, to amplify the input signal to generate a high band amplified signal. The output matching network includes a single output port and is configured to filter at least one of the low band amplified signal and the high band amplified signal into a load through the single output port.

Abstract: A method and system use the mutual coupling property of multiple antenna elements for characterizing signal waveform distortion introduced by items in the signal path, including the antenna elements, of a radio frequency transmit/receive system. The method and system alleviate the need for external test equipment by using the same hardware used in standard operation of the transmit/receive system for performing waveform distortion characterization through the generation, mutual coupling, and acquisition of a reference signal. In an embodiment involving application of complementary inverse predistortion to generation of an operational signal and/or to processing of a received operational signal, the signal as received and processed during standard system operation is compensated for distortion contributed by system hardware, improving impulse response and system performance.

Abstract: A method and system use the mutual coupling property of multiple antenna elements for characterizing signal waveform distortion introduced by items in the signal path, including the antenna elements, of a radio frequency transmit/receive system. The method and system alleviate the need for external test equipment by using the same hardware used in standard operation of the transmit/receive system for performing waveform distortion characterization through the generation, mutual coupling, and acquisition of a reference signal. In an embodiment involving application of complementary inverse predistortion to generation of an operational signal and/or to processing of a received operational signal, the signal as received and processed during standard system operation is compensated for distortion contributed by system hardware, improving impulse response and system performance.

Abstract: A method and system use the mutual coupling property of multiple antenna elements for measuring differences in propagation time among various signal paths involving antenna elements in a radio frequency transmit/receive system. The method and system alleviate the need for external test equipment by using the same hardware used in standard operation of the transmit/receive system for performing propagation time measurement through the generation, mutual coupling, and acquisition of a specially selected reference signal. In an embodiment involving calibration of various signal paths to realize matched propagation times, the signal energy returned through these various paths during standard system operation arrives for acquisition more closely coincident in time, increasing the instantaneous bandwidth of the system.

Abstract: An element support and thermal control arrangement for an active array antenna, preferably modular, using line-replaceable units (LRUs), includes a radiating-side liquid-cooled cold plate lying parallel with a liquid-cooled TR coldplate. Antenna elements are supported and cooled by the radiating cold plate, and a beamformer lies between the radiating and TR coldplates. A plurality of column coldplates are attached to the rear of the TR coldplate and define bays or volumes in which power LRUs can be fitted in thermal communication with the TR coldplate, the column coldplates, or both.

Abstract: An element support and thermal control arrangement for an active array antenna, preferably modular, using line-replaceable units (LRUs), includes a radiating-side liquid-cooled cold plate lying parallel with a liquid-cooled TR coldplate. Antenna elements are supported and cooled by the radiating cold plate, and a beamformer lies between the radiating and TR coldplates. A plurality of column coldplates are attached to the rear of the TR coldplate and define bays or volumes in which power LRUs can be fitted in thermal communication with the TR coldplate, the column coldplates, or both.

Abstract: An antenna array coacts with a ground plane for radiation. Calibration of the array is accomplished with the aid of one or more extensible calibration antenna elements, such as monopole antenna elements. Each calibration monopole is ordinarily retracted below the ground plane and is not “energized.” When calibration is desired, it is extended to protrude above the ground plane so as to achieve mutual coupling with one or more of the elements of the array antenna. Calibration signals may be passed in either direction. The calibration antenna may be extended/retracted by vacuum, mechanical device, or electrical motor.

Abstract: An array of thick flared notch radiators, wherein the separation distance between adjacent pairs of flared notch sticks is set to be less than one-half wavelength at the highest frequency of concern. The separation distance suppresses the propagation of higher order modes along the length of the sticks, which would degrade the array performance. The separation distance is achieved by fabricating the sticks with an increased thickness, thereby reducing the stick-to-stick channel width.

Abstract: Ferro-electric frequency selective surface radomes that have dielectric layers that comprise voltage controlled material, and the electrical properties of the dielectric layers are voltage controlled. By varying the dielectric properties, the passband frequency of the radomes can be shifted to optimize frequency and angular response of the frequency selective surface. The radomes comprise grating screens having a plurality of printed radiating elements. Inner and outer voltage controlled dielectric layers are disposed on the grating screens. Relatively high ohms per square resistive films are disposed on exposed surfaces of the voltage controlled dielectric layers.

Abstract: An impregnated carbon film expanded into a honeycomb structure is employed in a tapered notch phased array antenna and is used to absorb cross-polarized incident fields to reduce the reflections from shorted TEM parallel plate modes existing between radiator elements of the antenna. The carbon loading used to achieve this absorption may comprise a resistive taper, or analog circuit or anisotropic elements having a predetermined tapering resistive profile. The honeycomb cross-polarized load of the present invention provides the electrical performance necessary to meet tapered notch phased array antenna electrical requirements while reducing the weight and cost of antennas in which it is employed.

Abstract: An asymmetrical notch radiating element comprising a metal or metal-clad dielectric substrate into which a tapered slot or notch is disposed. The direction of the axis of the tapered slot lies along any preselected axis and is not constrained to be collinear with the normal to the aperture of the element. An asymmetrical antenna array comprises a plurality of asymmetrical notch radiating elements as described above. Each of the plurality of radiating elements is disposed such that the apertures of each of the elements are substantially coplanar and are at an angle relative to the notch axis. The present antenna uses asymmetric slot lines to control the antenna's electrical performance. The precise slot dimensions are chosen to optimize radiation and reduce scattering. The asymmetric flared notch allows optimization of the transmit gain in a direction that is not necessarily normal to the array surface.