Abstract: An electromagnetic energy absorber comprising a thin electrically-conductive ground plane as a base. Dielectric layers are positioned over the ground plane and high impedance surface (HIS) as a top layer. The impedance layer can be formed by loading the lumped resistor to a metallic grating like an FSS (Frequency Selective Surface). An air-spacer between the substrates has replaced the problem of the large electrical thickness of the substrate with effective permittivity. Metamaterial structures enable control over the resonant frequencies, and performance is enhanced over a broad frequency band. In addition, two broadband reflective-type linear to orthogonal polarization converters are disclosed that provide improved bandwidth and angular stability performance.

Abstract: A tunable passband filter including a signal input port for receiving an input radio frequency (RF) signal, a signal output port for transmitting a filtered output RF signal, a first high-pass section having a first tunable microelectromechanical system (MEMS) switch array to receive the input RF signal from the signal input port, a second high-pass section having a second tunable MEMS switch array to transmit the output RF signal to the signal output port, and a low pass section operatively coupled between the first high-pass section and the second high-pass section, and having each of a first tunable MEMS bridge array, a second tunable MEMS bridge array, and a high impedance line. The tunable passband filter is configured to filter the input RF signal to yield the filtered output RF signal.

Abstract: The present disclosure provides several embodiments of integrated conformal antennas that are designed to be integrated into handheld devices and support operation at millimeter-wave operating frequency band that includes 28 GHz. The antennas have low mutual coupling despite close proximity, and maintain a front-to-back radiation ratio of 10 dB or better within the operating frequency band. The integrated conformal antennas are further capable of supporting operation of the device in different orientations, different forward gains, or a combination thereof.

Abstract: The present disclosure provides several embodiments of integrated conformal antennas that are designed to be integrated into handheld devices and support operation at millimeter-wave operating frequency band that includes 28 GHz. The antennas have low mutual coupling despite close proximity, and maintain a front-to-back radiation ratio of 10 dB or better within the operating frequency band. The integrated conformal antennas are further capable of supporting operation of the device in different orientations, different forward gains, or a combination thereof.

Abstract: A tunable multi-mode laser is configured to generate a multi-mode optical signal at a tuned wavelength. The laser includes a semiconductor optical gain region, a feedback region, and a phase modulation region between the gain and feedback regions. Each of the regions may be monolithically integrated. A feedback loop is coupled to the tunable laser to receive the optical signal and includes at least one delay line. The delay line may also be monolithically integrated. An output of the delay line is fed back to the tunable multi-mode laser in order to provide at least one of self-injection locking and self-phase locked looping for the multi-mode tunable laser. Each of the optical gain region and phase modulation region of the laser is biased by the output of the delay line in order to reduce phase drift of the optical signal.

Abstract: An electromagnetic energy absorber comprising a thin electrically-conductive ground plane as a base. Dielectric layers are positioned over the ground plane and high impedance surface (HIS) as a top layer. The impedance layer can be formed by loading the lumped resistor to a metallic grating like an FSS (Frequency Selective Surface). An air-spacer between the substrates has replaced the problem of the large electrical thickness of the substrate with effective permittivity. Metamaterial structures enable control over the resonant frequencies, and performance is enhanced over a broad frequency band. In addition, two broadband reflective-type linear to orthogonal polarization converters are disclosed that provide improved bandwidth and angular stability performance.

Abstract: An electromagnetic bandgap (EBG) structure for improving isolation characteristics between antennas of a MIMO antenna array. The structure includes an EBG unit cell formed on a metal layer over a composite dielectric substrate and over a ground plane. The ground plane may include a defected ground structure to further improve isolation, and another metal layer including a substrate integrated waveguide may be included at an interface of the composite dielectric substrate.

Abstract: A frequency selective surface (FSS) having periodicity between one eighth and one quarter of an operational wavelength of the FSS and a low profile. The FSS has multiple pattern elements which are used to produce multiple transmission poles, and in some embodiments multiple transmission zeros. The transmission poles and transmission zeros are in the Ka and Ku bands, making the FSS applicable to 5G application. The transmission poles and transmission zeros also have high angular stability an oblique incident angle as high as 60°, as well as polarization insensitivity.

Abstract: A frequency selective surface (FSS) having periodicity between one eighth and one quarter of an operational wavelength of the FSS and a low profile. The FSS has multiple pattern elements which are used to produce multiple transmission poles, and in some embodiments multiple transmission zeros. The transmission poles and transmission zeros are in the Ka and Ku bands, making the FSS applicable to 5G application. The transmission poles and transmission zeros also have high angular stability an oblique incident angle as high as 60°, as well as polarization insensitivity.

Abstract: An electromagnetic bandgap (EBG) structure for improving isolation characteristics between antennas of a MIMO antenna array. The structure includes an EBG unit cell formed on a metal layer over a composite dielectric substrate and over a ground plane. The ground plane may include a defected ground structure to further improve isolation, and another metal layer including a substrate integrated waveguide may be included at an interface of the composite dielectric substrate.

Abstract: A tunable passband filter including a signal input port for receiving an input radio frequency (RF) signal, a signal output port for transmitting a filtered output RF signal, a first high-pass section having a first tunable microelectromechanical system (MEMS) switch array to receive the input RF signal from the signal input port, a second high-pass section having a second tunable MEMS switch array to transmit the output RF signal to the signal output port, and a low pass section operatively coupled between the first high-pass section and the second high-pass section, and having each of a first tunable MEMS bridge array, a second tunable MEMS bridge array, and a high impedance line. The tunable passband filter is configured to filter the input RF signal to yield the filtered output RF signal.

Abstract: An electromagnetic energy absorber comprising a thin electrically-conductive ground plane as a base. Dielectric layers are positioned over the ground plane and high impedance surface (HIS) as a top layer. The impedance layer can be formed by loading the lumped resistor to a metallic grating like an FSS (Frequency Selective Surface). An air-spacer between the substrates has replaced the problem of the large electrical thickness of the substrate with effective permittivity. Metamaterial structures enable control over the resonant frequencies, and performance is enhanced over a broad frequency band. In addition, two broadband reflective-type linear to orthogonal polarization converters are disclosed that provide improved bandwidth and angular stability performance.

Abstract: The present disclosure provides several embodiments of integrated conformal antennas that are designed to be integrated into handheld devices and support operation at millimeter-wave operating frequency band that includes 28 GHz. The antennas have low mutual coupling despite close proximity, and maintain a front-to-back radiation ratio of 10 dB or better within the operating frequency band. The integrated conformal antennas are further capable of supporting operation of the device in different orientations, different forward gains, or a combination thereof.

Abstract: A tunable multi-mode laser is configured to generate a multi-mode optical signal at a tuned wavelength. The laser includes a semiconductor optical gain region, a feedback region, and a phase modulation region between the gain and feedback regions. Each of the regions may be monolithically integrated. A feedback loop is coupled to the tunable laser to receive the optical signal and includes at least one delay line. The delay line may also be monolithically integrated. An output of the delay line is fed back to the tunable multi-mode laser in order to provide at least one of self-injection locking and self-phase locked looping for the multi-mode tunable laser. Each of the optical gain region and phase modulation region of the laser is biased by the output of the delay line in order to reduce phase drift of the optical signal.

Abstract: A microelectromechanical switch having improved isolation and insertion loss characteristics and reduced liability for stiction. The switch includes a signal line having an input port and an output port between first and second ground planes. The switch also includes a beam for controlling activation of the switch. In some embodiments, the switch further includes one or more defected ground structures formed in the first and second ground planes, and a corresponding secondary deflectable beam positioned over each defected ground structure. In some embodiments, the switch includes a metamaterial structure for generating a repulsive Casimir force.

Abstract: The present disclosure provides for a microelectromechanical switch including a first port (e.g., input port), one or more second ports (e.g., output ports), a cantilever beam, and a mechanical spring connected to the cantilever beam for providing a mechanical force to move the cantilever beam. The cantilever beam extends from a first end, which is in contact with either the first port or one of the second ports, to a second end that is switchably connectable to the other of the first port or said one of the second ports. The first and second ports and cantilever beam may be formed in a coplanar waveguide.

Abstract: The present disclosure provides for a phase shifter having at least one phase shift section. The phase shift section includes an input port for receiving an incoming radio frequency signal, an output port for transmitting an outgoing radio frequency signal, an input junction coupled to the input port, an output junction coupled to the output port, and a plurality of transmission lines. The input junction includes a first plurality of cantilever type switches, and the output junction includes a second plurality of cantilever type switches. Each transmission line connects one of the first plurality of cantilever type switches to a corresponding one of the second plurality of cantilever type switches. The first plurality of cantilever type switches, the second plurality of cantilever type switches, and the plurality of transmission lines are formed in a coplanar waveguide.

Abstract: The present disclosure is directed to a balun circuit adapted to operate at a frequency of between about 5 GHz to about 110 GHz. The balun circuit includes first and second output striplines and an input stripline formed on a first surface of the substrate, and a slotline formed on a second surface of the substrate opposite the first surface. The slotline has first and second ends, the first end overlapping the first output stripline and the second end overlapping the second output stripline, and the input stripline overlapping the slotline midway between the first end and the second end.

Abstract: A microelectromechanical switch having improved isolation and insertion loss characteristics and reduced liability for stiction. The switch includes a signal line having an input port and an output port between first and second ground planes. The switch also includes a beam for controlling activation of the switch. In some embodiments, the switch further includes one or more defected ground structures formed in the first and second ground planes, and a corresponding secondary deflectable beam positioned over each defected ground structure. In some embodiments, the switch includes a metamaterial structure for generating a repulsive Casimir force.

Abstract: The present disclosure is directed to a balun circuit adapted to operate at a frequency of between about 5 GHz to about 110 GHz. The balun circuit includes first and second output striplines and an input stripline formed on a first surface of the substrate, and a slotline formed on a second surface of the substrate opposite the first surface. The slotline has first and second ends, the first end overlapping the first output stripline and the second end overlapping the second output stripline, and the input stripline overlapping the slotline midway between the first end and the second end.