Abstract: A method of changing phase of a microwave electromagnetic beam in free space is provided wherein a cascade of device layers is located transverse to a path of the microwave beam. Each of the device layers have one or more columns. Each column has a device combination series-coupled to an adjacent device combination in the column. Each device combination has a first device having inductive characteristics at microwave frequencies and a second device series-coupled to the first device. The second device has at microwave frequencies characteristics of a fixed capacitance in parallel with a variable capacitance. The capacitance of one or more of the second devices is variable to establish a desired phase shift and a desired frequency band edge within a desired frequency pass band.

Abstract: Low cost millimeter wave imagers using two-dimensional focal plane arrays based on backward tunneling diode (BTD) detectors. Two-dimensional focal arrays of BTD detectors are used as focal plane arrays in imagers. High responsivity of BTD detectors near zero bias results in low noise detectors that alleviate the need for expensive and heat generating low noise amplifiers or Dicke switches in the imager. BTD detectors are installed on a printed circuit board using flip chip packaging technology and horn antennas direct the waves toward the flip chip including the BTD detectors. The assembly of the horn antennas, flip chips, printed circuit board substrate, and interconnects together work as an imaging sensor. Corrugated surfaces of the components prevent re-radiation of the incident waves.

Abstract: A method of changing phase of a microwave electromagnetic beam in free space is provided wherein a cascade of device layers is located transverse to a path of the microwave beam. Each of the device layers have one or more columns. Each column has a device combination series-coupled to an adjacent device combination in the column. Each device combination has a first device having inductive characteristics at microwave frequencies and a second device series-coupled to the first device. The second device has at microwave frequencies characteristics of a fixed capacitance in parallel with a variable capacitance. The capacitance of one or more of the second devices is variable to establish a desired phase shift and a desired frequency band edge within a desired frequency pass band.

Abstract: Low cost millimeter wave imagers using two-dimensional focal plane arrays based on backward tunneling diode (BTD) detectors. Two-dimensional focal arrays of BTD detectors are used as focal plane arrays in imagers. High responsivity of BTD detectors near zero bias results in low noise detectors that alleviate the need for expensive and heat generating low noise amplifiers or Dicke switches in the imager. BTD detectors are installed on a printed circuit board using flip chip packaging technology and horn antennas direct the waves toward the flip chip including the BTD detectors. The assembly of the horn antennas, flip chips, printed circuit board substrate, and interconnects together work as an imaging sensor. Corrugated surfaces of the components prevent re-radiation of the incident waves.

Abstract: A circularly polarized antenna system having improved axial ratio is disclosed. The antenna system comprises a circularly-polarized antenna, and a high-impedance buffer surface, surrounding the circularly polarized antenna, and disposed between the circularly polarized antenna and a ground plane. The width of the high-impedance buffer surface between the circularly-polarized antenna and the ground plane is selected to achieve an H-plane radiation pattern substantially identical to an E-plane radiation pattern over a desired scan angle.