Abstract: The radar cross section (RCS) of a vehicle/antenna combination is reduced by using an antenna and ground plane which are of substantially the same area, and using a frequency selective surface (FSS) in the regions on the periphery of the ground plain where the FSS is designed to be transparent and thereby pass out-of-band frequencies, while reflecting one or more operating frequencies of the antenna. A multilayer absorber below the FSS absorbs the out-of-band frequencies that a larger ground plane may have otherwise reflected to the body of the vehicle to which the antenna is mounted.

Abstract: The suprastructure over a substrate integrated waveguide (SIW) can provide for beam scanning utilizing a reconfigurable metasurface. The reconfigurable metasurface will have a plurality of PIN diode arrays that can be turned ON and OFF. In one design, the length of the reconfigurable metasurface is effectively enlarged or reduced in size to achieve beam scanning. In another design the tilt angle of the reconfigurable metasurface is adjusted to achieve beam scanning. The suprastructure also can be modified with metallic offset wings, where two or more pairs of offset wing can form a horn shaped element. The presence of the wings or horn, as well as control of the size and number of the wings can improve the gain of the SIW. These two suprastructure improvements may be used in combination, and they may be used over classical slotted SIWs or over an SIW with curved sections between consecutive slots.

Abstract: Subreflectors for frequency-reuse types of satellite communication system which cover the S and C bands take the form of a three-dimensional waveguide with cross dipoles on each end, where each branch of each dipole is electrically connected by conductor that passes through the center of a substrate that fills the volume of the waveguide. The frequency selective surface sub-reflector is configured to permit the S-band antenna to transmit therethrough with an insertion loss of less than 0.5 decibels, and to reflect transmissions of the C-band antenna with transmissions through the frequency selective surface sub-reflector being less than 15 decibels.

Abstract: A substrate integrated waveguide (SIW) for phase shifter for millimeter wave applications has a waveguide with a plurality of curved sections and which passes through the substrate from a wave entry port to a wave exit port. The plurality of curved sections forms a serpentine path of curves in a first direction followed by curves in a second direction which are opposite the first direction. Phase shifting elements are positioned in the waveguide in each of the curved sections. The phase shifting elements may take the form of PIN diodes or a pattern of liquid metal filled vias in the waveguide.

Abstract: A character Identification method has been proposed to obtain a specific reaction of a tag inside a printed chipless RFID system on a lossy dielectric substrate. The proposed technique is based on the eigenmode resonance to generate weight excitation coefficients and to extract a desired current distribution induced on the tag illuminated by a transmitter/receiver antennas arrays using the SVD-eigenmodes. The proposed methodology is based on techniques such as the proposed regrouping method to create groups of tags and the correlation method applied between a measure receive signal and the receive signal belong the library (or the create database). This method allows the confirmation/or not of the belonging of the tag to a group and the recognition of the measure tag based on two important parameters: the magnitude and the phase of an identification vector. The CIM method allows the user to better distinguish the tag from others, and to improve the independence from the environment.

Abstract: An exemplary phase shifter is a waveguide with multiple alternate paths for waves. The phase shifter includes at least two alternative paths, one straight and one curved. Rounding, chamfer, or a combination of both are used at the corners where the path transitions from the straight waveguide section to the curved waveguide section or vice versa.

Abstract: A wind turbine with reduced electromagnetic scattering includes a wind turbine support structure having a cylindrical shape, a wind turbine blade supported by the wind support structure, and a plurality of multi-layer absorbers to limit the electromagnetic scattering, the absorber including at least cobalt ferrite alloy nano-particles, cobalt ferrite alloy nano-flakes, and air. The wind turbine blade includes a blade root, a blade tip opposite the blade root, and a blade middle part extending between the blade root and the blade tip. The plurality of multi-layer absorbers further includes a planar absorber that covers the wind turbine support structure, and a curved absorber that covers the middle part.

Abstract: The present disclosure provides a low-cost beam scanning antenna and method of beam scanning in which two phase shifts are performed in an array of antenna elements. One of the phase shifts is performed in discrete stepwise increments in a feedline of the antenna element and another phase shift is performed by radiating a signal through variable phase shifters. The amount of phase shift provided by the variable phase shifters is varied by changing a rotation angle of the variable phase shifters.

Abstract: The present disclosure provides a low-cost beam scanning antenna and method of beam scanning in which two phase shifts are performed in an array of antenna elements. One of the phase shifts is performed in discrete stepwise increments in a feedline of the antenna element and another phase shift is performed by radiating a signal through variable phase shifters. The amount of phase shift provided by the variable phase shifters is varied by changing a rotation angle of the variable phase shifters.

Abstract: A wind turbine with reduced electromagnetic scattering includes a wind turbine support structure having a cylindrical shape, a wind turbine blade supported by the wind support structure, and a plurality of multi-layer absorbers to limit the electromagnetic scattering, the absorber including at least cobalt ferrite alloy nano-particles, cobalt ferrite alloy nano-flakes, and air. The wind turbine blade includes a blade root, a blade tip opposite the blade root, and a blade middle part extending between the blade root and the blade tip. The plurality of multi-layer absorbers further includes a planar absorber that covers the wind turbine support structure, and a curved absorber that covers the middle part.

Abstract: The ferrite-loaded, Fabry-Perot Cavity antenna uses a novel superstrate based beam scanning/shaping mechanism by optimally placing three magnetized ferrite cylinders within the cavity. Beam scan in a certain direction required oppositely located ferrite cylinder to be axially biased using externally controlled DC magnetizing field. The FPC utilizes a composite dielectric superstrate to inversely relate the mainlobe-to-sidelobe ratio with scan-angle, which demonstrates larger reduction in side lobe level with increases angle of beam scan. The designed 10 GHz ferrite-loaded FPC antenna has dimensions of 6.4 cm×2 cm×1.6 cm. It achieves a ?10 dB impedance bandwidth of 525 MHz, directivity of 11.04 dB and a broadside beam steering range of ±12° for 200 kA/m (0.25 T) changes in the externally applied axial magnetizing field.

Abstract: A multifrequency antenna comprising a stack of nonconductive substantially planar substrates, with a conductive layer disposed on each substrate surface. A first substrate includes transmission lines disposed on a rear surface and a conducting layer on the other surface. A second substrate is stacked on the first substrate. A conducting layer is disposed on one side of the second substrate surface. Conducting layers disposed on first and second substrates include a plurality of slotted openings arrayed about an antenna axis. A third substrate stacked on the second substrate includes a conducting layer top. A lossy dielectric-magnetic material encloses sides and rear of the multifrequency antenna, to prevent electromagnetic energy penetration through the enclosure. An edge diffraction suppresser reflector is attached in the rear surface of the multifrequency antenna, and has two or more essentially circular, conducting plates and a multitude of conducting cylinders along the axis of the multifrequency antenna.

Abstract: A multifrequency antenna comprising a stack of nonconductive substantially planar substrates, with a conductive layer disposed on each substrate surface. A first substrate includes transmission lines disposed on a rear surface and a conducting layer on the other surface. A second substrate is stacked on the first substrate. A conducting layer is disposed on one side of the second substrate surface. Conducting layers disposed on first and second substrates include a plurality of slotted openings arrayed about an antenna axis. A third substrate stacked on the second substrate includes a conducting layer top. A lossy dielectric-magnetic material encloses sides and rear of the multifrequency antenna, to prevent electromagnetic energy penetration through the enclosure. An edge diffraction suppresser reflector is attached in the rear surface of the multifrequency antenna, and has two or more essentially circular, conducting plates and a multitude of conducting cylinders along the axis of the multifrequency antenna.

Abstract: A compact antenna for circular polarization comprises a substrate of a dielectric material which is formed on its bottom surface with a ground plane and on its top surface with four planar rectangular patches of an electrically conductive material. The four patches are mounted in a coplanar relation on the top surface of the substrate, and arranged along four sides of a square pattern with the length of each patch angled at 90.degree. with respect to the length of the two adjacent patches. Each of the four patches is short-circuited to the ground plane at a shorting point located at a corner of the square pattern. A 90.degree. hybrid circuit is connected to directly feed only the two adjacent patches with a phase difference of 90.degree. to thereby define these two patches as active antenna elements which are fed with 0.degree. and 90.degree. signals, respectively.

Abstract: A collision avoidance system for a vehicle has a vehicle steering sensor for sensing a direction in which the vehicle is being steered, a source of radiation, an articulated reflector for directing radiation from the source in a desired direction, an articulation mechanism for effecting articulation of the articulate reflector, and a close loop control circuit responsive to the vehicle steering sensor for controlling the articulation mechanism so as to cause the articulated reflector to direct radiation in a direction which is generally the same as that direction in which the vehicle is turning.

Abstract: An antenna apparatus for receiving two distinct frequencies in the MHz or GHz range. A patch layer of electrically conducting material is positioned in the interior of a dielectric layer that has top and bottom surfaces. First and second ground planes are positioned on the top and bottom surfaces of the substrate, respectively. The patch is electrically connected by plated via holes to an annular strip of conducting material, positioned on the top substrate surface and surrounding the first ground plane. A patch antenna for receiving a first frequency is thus formed by the patch layer and the second ground plane. A cavity antenna for receiving a second frequency is formed from the patch layer, the first ground plane, and the annular strip. Two receiver feed connections, positioned at selected first and second positions on the patch resonator, receive distinct first and second frequencies.

Abstract: Antenna apparatus for receiving two distinct frequencies in the MHz or GHz range. A resonator layer of electrically conducting material is positioned in the interior of a dielectric layer that has first and second opposed surfaces (front and back). First and second ground planes are positioned on the first and second opposed surfaces of the substrate. The resonator is electrically connected to an annular strip of conducting material, positioned on the first substrate surface and surrounding the first ground plane. Two receiver feed connections, positioned at selected first and second positions on the patch resonator, receive distinct first and second frequencies. This apparatus may be used to receive the two GPS operating frequencies, the two GLONASS operating frequencies or two wireless LAN operating frequencies.