Publications

This paper describes a method to answer the following questions: can several of the elements of a phased array be employed as auxiliary (AUX) elements and how can the phase of each be adjusted so that the (1) cross-polarization (cross-pol) isolation is minimized to 40 dB, (2) the sidelobe levels...

This paper summarizes the challenges in achieving (and even specifying) the antenna polarization accuracy requirements for the Multifunction Phased Array Radar (MPAR) and the progress that has been made towards meeting these requirements through demonstrations and theoretical investigations.

Superconducting qubits are electronic circuits comprising lithographically defined Josephson tunnel junctions, inductors, capacitors, and interconnects. When cooled to dillution refrigerator temperatures, these circuits behave as quantum mechanical "artificial atoms," exhibiting quantized states of electronic charge, magnetic flux, or junction phase depending on the design parameters of the constituent circuit elements...

Within DOT, the FAA has initiated an effort known as the NextGen Surveillance and Weather Radar Capability (NSWRC) to analyze the need for the next generation radar replacement and assess viable implementation alternatives. One concept under analysis is multifunction radar using phased-array technology -- Multifunction Phased Array Radar or MPAR.

A stepped notch antenna at Ku-band is developed to provide a thermal heat sink for active arrays. The antenna with forced air cooling provides up to 0.4 degrees C/W of thermal resistance. The antenna integration with a printed circuit board allows for high volume surface mount assembly of active devices.

Various RF circuit blocks implemented by using commercially available MEMS digital capacitor arrays are presented for reconfigurable RF systems. The designed circuit blocks are impedance-matching network, tunable bandpass filter, and VSWR sensor. The frequency range of the designed circuits is 0.4-4GHz. The MEMS digital capacitor arrays that are employed in...

We present a new method for determining pulse imperfections and improving the single-gate fidelity in a superconducting qubit. By applying consecutive positive and negative pi pulses, we amplify the qubit evolution due to microwave pulse distortions, which causes the qubit state to rotate around an axis perpendicular to the intended...

In the presence of time-reversal symmetry, quantum interference gives strong corrections to the electric conductivity of disordered systems. The self-interference of an electron wave function traveling time-reversed paths leads to effects such as weak localization and universal conductance fluctuations. Here, we investigate the effects of broken time-reversal symmetry in a...

Microwave photonic (MWP) links with a low noise figure and high dynamic range are required for antenna remoting, radio-over-fiber (RoF), and other advanced applications. MWP links have recently been demonstrated with noise figures approaching 3 dB, without any electrical preamplification, by using low-noise high-power laser sources in conjunction with efficient...

The Micro-sized Microwave Atmospheric Satellite (MicroMAS) is a 3U cubesat (34x10x10 cm, 4.5 kg) hosting a passive microwave spectrometer operating near the 118.75-GHz oxygen absorption line. The focus of the first MicroMAS mission (hereafter, MicroMAS-1) is to observe convective thunderstorms, tropical cyclones, and hurricanes from a near-equatorial orbit at approximately...