Engineering topics

Boreham, J. F.

Publications and source records attributed to Boreham, J. F..

5 records

NASA NTRS1986

Microwave Power Combiner With Switching Diodes

In multiple-port microwave power combiner, each of outputs of two or more power amplifiers of same frequency and phase passed to common output port separately or together. Each amplifier connected to combiner through switch consisting of resonant structures, radio-frequency chokes, and diode. Switches not only permit flexiblity in selection of amplifiers but isolate unused amplifiers from network, all while operating at relatively low power loss.

Conroy, B. L.↗

NASA NTRS1981

Total Hip Joint Replacement Biotelemetry System

The development of a biotelemetry system that is hermetically sealed within a total hip replacement implant is reported. The telemetry system transmits six channels of stress data to reconstruct the major forces acting on the neck of the prosthesis and uses an induction power coupling technique to eliminate the need for internal batteries. The activities associated with the telemetry microminiaturization, data recovery console, hardware fabrications, power induction systems, electrical and mechanical testing and hermetic sealing test results are discussed.

Boreham, J. F.↗

NASA NTRS1979

Evaluation of the JPL X-band 32 element active array

Tests performed on an X-band 32-element active array are described. Antenna pattern characteristics of the array were tested in its standard operating mode as well as several degraded performance modes, including failures of 1, 2, 3, 4, 8, 16, and 31 elements. Additionally, the array was characterized with the addition of a metallic shroud, and also characterized versus rf drive level and at a single off-axis electronic beamsteered position. Characterization was performed on several of the 3/4-watt, three-stage, X-band solid-state power amplifier modules. The characterization included swept amplitude response, amplitude and phase versus temperature from -20 to +60 C, and intermodulation distortion of selected modules. The array is described and conclusions and recommendations based upon the experience and results achieved are included.

Boreham, J. F.↗

NASA NTRS1974

Application of acoustic surface wave filter-beam lead component technology to deep space multimission hardware design

This paper discusses the utilization of acoustic surface wave filters, beam lead components, and thin film metallized ceramic substrate technology as applied to the design of deep space, long-life, multimission transponder. The specific design to be presented is for a second mixer local oscillator module, operating at frequencies as high as 249 MHz.

Kermode, A. W.↗

NASA NTRS1972

High power microstrip RF switches.

Description of a microstrip-type single-pole double-throw switch, which uses only two PIN diodes, eliminates usual dc blocking capacitors, and has demonstrated an RF power handling capacity greater than 100 W CW at S-band. The insertion loss is less than 0.25 dB, and the input-to-off port isolation is greater than 36 dB over a bandwidth larger than 30 MHz.

Choi, S. D.↗