Engineering topics

Davidson, Shayla E.

Publications and source records attributed to Davidson, Shayla E..

5 records

NASA NTRS1988

Distributed Architecture For Phased-Array Antennas

Distributed Architecture for Phased Array Antennas (DISTAR) computer program simulation tool used to study implementation of distributed phased-array equipment. Allows placement of possibly-faulty transmitting/receiving modules at locations throughout array. Variations in amplifiers and phase shifters degrades performance of antenna, depending on environmental conditions and array architecture. Enables antenna designer to examine characteristics of array and how they affect both types and extents of antenna failures. General specifications for amplifier and phase-shifter tolerances determined for various architectures. Written in FORTRAN 77.

Davidson, Shayla E.↗

NASA NTRS1988

Dual-Band Microstrip Antenna With Reactive Loading

Effective but bulky coaxial stub replaced. Short-circuited microstrip transmission line serves as reactive loading element for microstrip antenna. Constructed integrally with stripline radiating element, shorted line preserves low microstrip profile and enables tuning of antenna for two-band operation.

Davidson, Shayla E.↗

NASA NTRS1987

Designing Rectangular RHCP Microstrip Antennas

RHCP, Right-Handed, Circularly Polarized Microstrip Antenna program, aids in design of rectangular microstrip-antenna element, given desired frequency of operation and characteristics of substrate. Begins design calculations on basis of square element with linear polarization. Effective dielectric constant and changes in electrical length due to fringing at edges of radiating element taken into account. Coaxial feed inset with 50 ohms input impedance. Placement of feed such that two orthonormal modes produced in antenna cavity, right- or left-handed circular polarization obtained. Written in FORTRAN 77.

Davidson, Shayla E.↗

NASA NTRS1987

Waveguide-Horn-to-Waveguide Transition Assembly

Microstrip-to-waveguide transition integrated with waveguide-horn antenna element. Integrated transition assembly couples electromagnetic energy through horn and transition board to connector.

Davidson, Shayla E.↗

NASA NTRS1987

Phased array antenna for space shuttle orbiter

The National Aeronautics and Space Administration is developing a distributed phased array antenna at the Lyndon B. Johnson Space Center as a possible upgrade for the Space Shuttle Orbiter S-band phase modulation communications system. The antenna consists of an eight-element transmit section, eight-element receive section, and a single L-band receive element. The antenna design is constrained by the existing Orbiter system and space environment. The solution to the interface design problems led to an antenna system which provides improved link margins and yet supports previous operational configurations. This paper describes the system development, antenna hardware, and the interface consideration which led to the final design.

Davidson, Shayla E.↗