Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

performance of the microwave circuits and components comprising the systems. For example, power amplifiers with output powers
of several watts over broad bandwidths, low noise amplifiers with noise figures as low as 3 dB at 94 GHz, stable oscillators
with low noise characteristics and high output power, and electronically steerable antennas were required. In addition, the reliability
of the systems had to be increased because of the high monetary and human cost if a failure occurred. to achieve these goals,
industry, academia and the government agencies supporting them chose to develop technologies with the greatest possibility of
surpassing the state of the art performance. Thus, Si, which was already widely used for digital circuits but had material characteristics
that were perceived to limit its high frequency performance, was bypassed for a progression of devices starting with GaAs
Metal Semiconductor Field Effect Transistors (MESFETs) and ending with InP Pseudomorphic High Electron Mobility Transistors
(PHEMTs). For each new material or device structure, the electron mobility increased, and therefore, the high frequency characteristics
of the device were improved. In addition, ultra small geometry lithographic processes were developed to reduce the
gate length to 0.1 pm which further increases the cutoff frequency. The resulting devices had excellent performance through the
millimeter-wave spectrum.
Derived from text
Technology Assessment; Microwave Circuits; Millimeter Waves; Logic Circuits; High Electron Mobility Transistors; Silicon;
Germanium; Field Effect Transistors
20000064111 DYNACS Engineering Co., Inc., Brook Park, OH USA
Suspended Patch Antenna Array With Electromagnetically Coupled Inverted Microstrip Feed
Simons, Rainee N., DYNACS Engineering Co., Inc., USA; May 2000; 10p; In English; 6th; Ka Band Utilization, 31 May - 2 Jun.
2000, Cleveland, OH, USA; Sponsored by Istituto Internazionale delle Comunicazioni, Italy
Contract(s)/Grant(s): NAS3-98008; RTOP 632-6E-51
Report No.(s): NASA/CR-2000-210069; E-12247; NAS 1.26:210069; No Copyright; Avail: CASI; A02, Hardcopy; A01, Microfiche
The paper demonstrates a four-element suspended patch antenna array, with a parasitic patch layer and an electromagnetically
coupled inverted microstrip feed, for linear polarization at K-Band frequencies. This antenna has the following advantages over
conventional microstrip antennas: First, the inverted microstrip has lower attenuation than conventional microstrip; hence, conductor
loss associated with the antenna corporate feed is lower resulting in higher gain and efficiency. Second, conventional proximity
coupled patch antennas require a substrate for the feed and a superstrate for the patch. However, the inverted microstrip fed
patch antenna makes use of a single substrate, and hence, is lightweight and low cost. Third, electromagnetic coupling results in
wider bandwidth. Details regarding the design and fabrication will be presented as well as measured results including return loss,
radiation patterns and cross-polarization levels.
Author
Antenna Arrays; Performance Tests; Antenna Radiation Patterns; Cross Polarization; Fabrication; Linear Polarization; Patch
Antennas
20000064661 Abdus Salam International Centre for Theoretical Physics, Trieste, Italy
Second harmonics and compensation effect in ceramic superconductors
Mai Suan Li,; Sep. 30, 1998; 10p; In English
Report No.(s): DE99-609737; IC-98/141; No Copyright; Avail: Department of Energy Information Bridge
The nonlinear Alternating Current (AC) susceptibility and the compensation effect observed in ceramic superconductors
which show the paramagnetic Meissner effect are studied by the Monte Carlo simulations on a three dimensional lattice model
of the Josephson array with finite self-conductance. Our study is based on the possible existence of the chiral glass phase in these
materials. In agreement with experiments, the compensation effect is demonstrated to be present in d-wave superconductors but
not in the s-wave ones.
NTIS
Harmonics; Compensation; High Temperature Superconductors
20000064722 Naval Surface Warfare Center, Dahlgren Div., Dahlgren, VA USA
Electronic Equipment Handbook on Methods for Meeting U.S. Navy Shipboard Electrical Power Interface Requirements
Final Report
Hall, James R.; Apr. 2000; 26p; In English
Report No.(s): AD-A377030; NSWCDD/TR-00/33; No Copyright; Avail: CASI; A03, Hardcopy; A01, Microfiche
This handbook provides guidance for the implementation of electronic equipment suitable for U.S. Navy shipboard applications.
The primary focus of this handbook is on the electrical power interface between combat systems equipment and U.S. Navy
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