Abstract: An electrically small antenna system modulates the Q factor of the antenna during electrical transmission to decrease the Q factor during signal transitions between frequency states thereby affecting an improved trade-off between antenna bandwidth and operating efficiency.

Abstract: A phase shift element includes an antenna, a first dielectric layer, a ground plane mounted to a first surface of the first dielectric layer, a reflecting circuit, and a single antenna-reflector line connected between the antenna and the reflecting circuit through the ground plane and the first dielectric layer. The antenna-reflector line is formed of a conducting material. The reflecting circuit is mounted to a second surface of the first dielectric layer. The first surface is opposite the second surface. The reflecting circuit is configured to reflect a signal received on the single antenna-reflector line from the antenna back to the antenna on the single antenna-reflector line. The reflecting circuit is further configured to be switchable between four different impedance levels that each provide a different phase shift when the signal is reflected by the reflecting circuit.

Abstract: A phase shift element includes an antenna, a first dielectric layer, a ground plane mounted to a first surface of the first dielectric layer, a reflecting circuit, and a single antenna-reflector line connected between the antenna and the reflecting circuit through the ground plane and the first dielectric layer. The antenna-reflector line is formed of a conducting material. The reflecting circuit is mounted to a second surface of the first dielectric layer. The first surface is opposite the second surface. The reflecting circuit is configured to reflect a signal received on the single antenna-reflector line from the antenna back to the antenna on the single antenna-reflector line. The reflecting circuit is further configured to be switchable between two different impedance levels that each provide a different phase shift when the signal is reflected by the reflecting circuit.

Abstract: A phase shift element includes an antenna, a first dielectric layer, a ground plane mounted to a first surface of the first dielectric layer, a reflecting circuit, and a single antenna-reflector line connected between the antenna and the reflecting circuit through the ground plane and the first dielectric layer. The antenna-reflector line is formed of a conducting material. The reflecting circuit is mounted to a second surface of the first dielectric layer. The first surface is opposite the second surface. The reflecting circuit is configured to reflect a signal received on the single antenna-reflector line from the antenna back to the antenna on the single antenna-reflector line. The reflecting circuit is further configured to be switchable between four different impedance levels that each provide a different phase shift when the signal is reflected by the reflecting circuit.

Abstract: A phase shift element includes an antenna, a first dielectric layer, a ground plane mounted to a first surface of the first dielectric layer, a reflecting circuit, and a single antenna-reflector line connected between the antenna and the reflecting circuit through the ground plane and the first dielectric layer. The antenna-reflector line is formed of a conducting material. The reflecting circuit is mounted to a second surface of the first dielectric layer. The first surface is opposite the second surface. The reflecting circuit is configured to reflect a signal received on the single antenna-reflector line from the antenna back to the antenna on the single antenna-reflector line. The reflecting circuit is further configured to be switchable between two different impedance levels that each provide a different phase shift when the signal is reflected by the reflecting circuit.

Abstract: A phase shift element includes a first dielectric layer, a conductive layer, a second dielectric layer, a conducting pattern layer, switches, and vertical interconnect accesses (vias). Each conductor of a plurality of conductors of the conducting pattern layer is orthogonal to two other conductors. Each switch is switchable between a conducting position and a non-conducting position. Each via is connected to a single conductor. The first conductive material reflects an electromagnetic wave incident on the conducting pattern layer and on the second dielectric layer. When a switch is in the conducting position, the switch electrically connects two conductors to each other through their respective vias. A plurality of different switch configurations of the switches provide a 2-bit phase quantization on the reflected electromagnetic wave relative to the electromagnetic wave incident on the conducting pattern layer when the electromagnetic wave is incident on the conducting pattern layer.

Abstract: A waveguide includes a first double-ridge waveguide, a second double-ridge waveguide, and a polarization rotator. The first double-ridge waveguide provides a phase of an input electrical field rotated 0° or 90°. The second double-ridge outputs an electric field with a polarization that is perpendicular to a first polarization of the input electrical field. The polarization rotator is mounted between the first double-ridge waveguide and the second double-ridge waveguide and includes a frame, a dielectric layer, a first conducting pattern layer forming a first conductor and a second conductor, a first switch connected between the first conductor and the second conductor, a second conducting pattern layer forming a third conductor and a fourth conductor, and a second switch connected between the third conductor and the fourth conductor. Wherein a phase rotation of 90° or ?90° is provided by the polarization rotator based on a state of the first and second switch.

Abstract: A phase shift element includes a first dielectric layer, a conductive layer, a second dielectric layer, a conducting pattern layer, switches, and vertical interconnect accesses (vias). Each conductor of a plurality of conductors of the conducting pattern layer is orthogonal to two other conductors. Each switch is switchable between a conducting position and a non-conducting position. Each via is connected to a single conductor. The first conductive material reflects an electromagnetic wave incident on the conducting pattern layer and on the second dielectric layer. When a switch is in the conducting position, the switch electrically connects two conductors to each other through their respective vias. A plurality of different switch configurations of the switches provide a 2-bit phase quantization on the reflected electromagnetic wave relative to the electromagnetic wave incident on the conducting pattern layer when the electromagnetic wave is incident on the conducting pattern layer.

Abstract: A waveguide includes a first double-ridge waveguide, a second double-ridge waveguide, and a polarization rotator. The first double-ridge waveguide provides a phase of an input electrical field rotated 0° or 90°. The second double-ridge outputs an electric field with a polarization that is perpendicular to a first polarization of the input electrical field. The polarization rotator is mounted between the first double-ridge waveguide and the second double-ridge waveguide and includes a frame, a dielectric layer, a first conducting pattern layer forming a first conductor and a second conductor, a first switch connected between the first conductor and the second conductor, a second conducting pattern layer forming a third conductor and a fourth conductor, and a second switch connected between the third conductor and the fourth conductor. Wherein a phase rotation of 90° or ?90° is provided by the polarization rotator based on a state of the first and second switch.

Abstract: An antenna system is provided that includes a coaxial cable, an antenna, a reflector wall, and a slot wall. The reflector wall is formed of a conductive material connected to a conductive shield to extend in an axial direction, is separated from an antenna conductor by a second dielectric material in a radial direction relative to the antenna conductor, and partially surrounds the antenna conductor in the radial direction from a first angle to a second angle when projected into a radial plane. The slot wall is formed through a portion of the conductive shield to expose a dielectric material from a third angle to a fourth angle when projected into the radial plane, is formed on a first side relative to a base. The first angle, the second angle, the third angle, and the fourth angle are defined relative to a common axis parallel to the radial plane.

Abstract: A multiple band phase shifter includes a first dielectric layer, a conductive layer, a second dielectric layer, and for each central operating frequency of a plurality of central operating frequencies, a switch, a plurality of vias, and a conducting pattern layer. Each via is formed of a conductive material that extends through the first dielectric layer, through a third dielectric material formed in and through the conductive layer, and through the second dielectric layer and is connected to a first throw arm or a second throw arm of the switch. The conducting pattern layer includes conductors electrically connected to a distinct via. An electric polarization of a reflected electromagnetic wave is rotated by 90 degrees when the switch is positioned in the first conducting position and the electric polarization of the reflected electromagnetic wave is rotated by ?90 degrees when the switch is positioned in the second conducting position.

Abstract: A magneto-inductive transmit antenna is provided that includes a shield formed of a magnetic material, a magnetic field source mounted on a first side of the shield, and a coil wrapped around the shield to define a number of turns. The coil is configured to conduct a current therethrough. The magnetic material is configured to exhibit a change in permeability based on the current conducted through the coil when the current is conducted through the coil. The change in permeability is configured to modulate a magnetic field of the magnetic field source. The magnetic field is modulated relative to a second side of the shield opposite the first side when the permeability is changed.

Abstract: An antenna system is provided. The antenna system includes a coaxial cable, an antenna, and an impedance matching structure. The coaxial cable includes a center conductor extending a length of the coaxial cable, a dielectric material surrounding the center conductor along the length of the coaxial cable, and a conductive shield surrounding the dielectric material along the length of the coaxial cable. The antenna includes a conductor having an electrical length of half a wavelength at a selected operating frequency. The impedance matching structure includes a second center conductor mounted between an end of the center conductor of the coaxial cable and a feed end of the antenna. The impedance matching structure is configured to match an impedance of the coaxial cable to an impedance of the antenna.

Abstract: A phase shifter includes a first dielectric layer, a switch mounted to the first dielectric layer, a conductive layer mounted to the first dielectric layer, a second dielectric layer mounted to the conductive layer, a conducting pattern layer mounted to the second dielectric layer, and a plurality of vias. The switch is switchable between a first conducting position and a second conducting position. Each via is connected between a first or a second throw arm of the switch and a conductor of the conducting pattern layer. When an electromagnetic wave incident on the phase shifter is reflected, an electric polarization of the reflected electromagnetic wave is rotated by ±90 degrees compared to an electric polarization of the incident electromagnetic wave based on a conducting position of the switch. The phase shifter can be used as one-bit spatial phase shifter to provide either 0° or 180° phase shift over wide bandwidths.

Abstract: A multiple band phase shifter includes a first dielectric layer, a conductive layer, a second dielectric layer, and for each central operating frequency of a plurality of central operating frequencies, a switch, a plurality of vias, and a conducting pattern layer. Each via is formed of a conductive material that extends through the first dielectric layer, through a third dielectric material formed in and through the conductive layer, and through the second dielectric layer and is connected to a first throw arm or a second throw arm of the switch. The conducting pattern layer includes conductors electrically connected to a distinct via. An electric polarization of a reflected electromagnetic wave is rotated by 90 degrees when the switch is positioned in the first conducting position and the electric polarization of the reflected electromagnetic wave is rotated by ?90 degrees when the switch is positioned in the second conducting position.

Abstract: An antenna includes a first dipole arm and a second dipole arm. The first dipole arm is connected to a first conductor and is formed of a first conducting material. The first dipole arm extends in an axial direction from the first conductor. The second dipole arm is connected to a second conductor that is distinct from the first conductor and is formed of a second conducting material. The second dipole arm extends in the axial direction from the second conductor and is wound around the first dipole arm to form a number of loops. The second dipole arm does not contact the first dipole arm. An axial length of the second dipole arm in the axial direction is less than 90% of an axial length of the first dipole arm in the axial direction.

Abstract: A magneto-inductive transmit antenna is provided that includes a shield formed of a magnetic material, a magnetic field source mounted on a first side of the shield, and a coil wrapped around the shield to define a number of turns. The coil is configured to conduct a current therethrough. The magnetic material is configured to exhibit a change in permeability based on the current conducted through the coil when the current is conducted through the coil. The change in permeability is configured to modulate a magnetic field of the magnetic field source. The magnetic field is modulated relative to a second side of the shield opposite the first side when the permeability is changed.

Abstract: A system and method for an electron paramagnetic resonance imaging (EPRI) system includes a magnet configured to apply a static magnetic field to a subject to be imaged and a gradient coil configured to apply a magnetic field gradient to the static magnetic field. The system also includes a parallel plate waveguide (PPWG) configured to use a traveling wave to generate a radio frequency (RF) magnetic field over a volume of interest (VOI) in the subject to elicit EPRI data from the VOI and a processor configured to reconstruct the EPRI data into an image of the VOI.

Abstract: A balun includes a center conductor, a dielectric material, a tapered wall, a ring, and a prong. The center conductor extends a length of the balun. The dielectric material surrounds the center conductor along the length of the balun. The tapered wall forms a portion of a tube between a first wall and a second wall. The first wall is opposite the second wall. The tapered wall is formed of a conductive material. The portion of the tube forms a slot exposing the dielectric material. The ring connects to the second wall of the tapered wall and is formed of the conductive material. The ring forms a tube surrounding the center conductor and the dielectric material. The prong connects to the ring to extend toward the first wall and is formed of the conductive material. The prong extends over a portion of the dielectric material exposed by the slot.

Abstract: A phase shifter includes a first dielectric layer, a switch mounted to the first dielectric layer, a conductive layer mounted to the first dielectric layer, a second dielectric layer mounted to the conductive layer, a conducting pattern layer mounted to the second dielectric layer, and a plurality of vias. The switch is switchable between a first conducting position and a second conducting position. Each via is connected between a first or a second throw arm of the switch and a conductor of the conducting pattern layer. When an electromagnetic wave incident on the phase shifter is reflected, an electric polarization of the reflected electromagnetic wave is rotated by ±90 degrees compared to an electric polarization of the incident electromagnetic wave based on a conducting position of the switch. The phase shifter can be used as one-bit spatial phase shifter to provide either 0° or 180° phase shift over wide bandwidths.