Engineering topics

Cramer, P. W., Jr.

Publications and source records attributed to Cramer, P. W., Jr..

4 records

NASA NTRS1985

Beam forming network

The network, which is connected to a layer of 134 feed elements that transmit and receive microwaves, consists of a pair of circuit boards parallel to the feed element layer. One of the two boards has 87 dividers that each divide a signal to be transmitted into seven portions, and the other board has 134 combiners that each collect seven transmit signal portions and deliver the sum to one of the feed elements. A similar arrangement is used to handle received signals. The large number of interconnections are made by printed circuit conductors radiating from each of the numerous dividers and combiners, and by providing interconnection pins that interconnect the ends of pairs of conductors lying on the two boards. The printed circuit conductors extend in undulating paths that provide maximum separation of conductors to minimize crosstalk.

Cramer, P. W., Jr.↗

NASA NTRS1981

Determination of specular points on a surface of revolution

For a given source and observation point, specular points on a conducting surface must be found in order to apply the geometrical optics theory to calculate the reflected field. An efficient method is presented for finding all the specular points for the special case in which the conducting surface is a part of a surface of revolution. Our method, which reduces the conventional two-dimensional search to a one-dimensional search also makes it economically feasible to obtain a global solution for certain classes of surface, source, and observation point geometries that do not render solutions in the more conventional two-dimensional searches.

Lee, S. W.↗

NASA NTRS1979

Limited scan dual-band high-gain antenna

Dual band communication and tracking antenna concept combines S- and X-band high gain performance in near field cassagrainian configuration. Design incorporating subreflector in near field of feed permits limited electronic scanning with phased array feed of approximately subreflector size placed in region between subreflector and main reflector.

Cramer, P. W., Jr.↗

NASA NTRS1973

Conical quadreflex antenna analytical study

A method for evaluating the performance of a four-reflection or quadreflex antenna is reported. Geometrical optics was used initially to determine the ideal feed pattern required to produce uniform illumination on the aperture of the conical reflector and the reverse problem of quickly finding the aperture illumination given an arbitrary feed pattern. The knowledge of the aperture illumination makes it possible to compute the antenna efficiency, which is useful for comparing antenna performance during tradeoff studies. Scattering calculations, using physical optics techniques, were then used to more accurately determine the performance of a specific design.

Cramer, P. W., Jr.↗