Engineering topics
Publications and source records attributed to Estep, H..
A study of the relative merits of ELT antenna positions, when mounted on a small aircraft, is presented. The gain distribution of the best antenna position together with the worst crash scenario is also given.
It is noted that the stringent economy of data-collection systems consisting of several widely dispersed satellite-monitored sensor platforms can be partially achieved by using an inexpensive linearly polarized antenna on each platform and that due to Faraday rotation of the ionosphere, the satellite antenna must be circularly polarized to avoid a prohibitive polarization loss. The cumulative probability distribution of polarization loss between a linearly polarized platform antenna and an elliptically polarized satellite antenna is computed for satellite-antenna axial ratios of 3 and 4 dB. The results indicate that a polarization loss of 4.5 dB must be expected for a reliability of 85% and an axial ratio of 3 dB. It is suggested that the conventional assignment of a 3-dB polarization loss to the communication link considered may not insure the required link reliability.
Ground antenna configuration for Ku band tracking and data relay satellite
Dichroic surface has high stopband filter characteristics with a low stopband-to-passband frequency ratio. It utilizes two stagger-tuned, resonant artificial dielectric surfaces and is virtually polarization insensitive.