Engineering topics

Hussein, Ziad

Publications and source records attributed to Hussein, Ziad.

4 records

NASA NTRS2006

Interferometric System for Measuring Thickness of Sea Ice

The cryospheric advanced sensor (CAS) is a developmental airborne (and, potentially, spaceborne) radar-based instrumentation system for measuring and mapping the thickness of sea ice. A planned future version of the system would also provide data on the thickness of snow covering sea ice. Frequent measurements of the thickness of polar ocean sea ice and its snow cover on a synoptic scale are critical to understanding global climate change and ocean circulation.

Hussein, Ziad↗

NASA NTRS2005

A wide-band dual-polarized VHF microstrip antenna for global sensing of sea ice thickness

A VHF microstrip patch antenna was developed to achieve a bandwidth of 45 MHz (30%) from 127 MHz to 172 MHz with dual-linear-polarization capability. This microstrip antenna used foam substrates and dual stacked patches with capacitive probe feeds to achieve wide bandwidth. Four such capacitive feeds were used to achieve dual polarizations with less than -20 dB of cross-polarization level. Twenty-four shorting pins were used on the lower patch to achieve acceptable isolation between the four feed probes. This antenna has a measured gain of 8.5 dB at 137 MHz and 10 dB at 162 MHz. By using the Method of Moments technique, multipath scattering patterns were calculated when the antenna is mounted on the outside of a Twin Otter aircraft.

VHF↗

NASA NTRS2003

Cylindrical Antenna With Partly Adaptive Phased-Array Feed

A proposed design for a phased-array fed cylindrical-reflector microwave antenna would enable enhancement of the radiation pattern through partially adaptive amplitude and phase control of its edge radiating feed elements. Antennas based on this design concept would be attractive for use in radar (especially synthetic-aperture radar) and other systems that could exploit electronic directional scanning and in which there are requirements for specially shaped radiation patterns, including ones with low side lobes. One notable advantage of this design concept is that the transmitter/ receiver modules feeding all the elements except the edge ones could be identical and, as a result, the antenna would cost less than in the cases of prior design concepts in which these elements may not be identical.

Hussein, Ziad↗

NASA NTRS1998

In-Situ Radars For Sounding of Mars and Europa

One of fundamental problems in the Mars science is the determination of Martian volatile budget. Of Primary importance is the knowledge of the planetwide distribution of ground ice.

Mars Europa Ice Mars Rover Europa Lander↗