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Title: Beam spoiling a reflector antenna with conducting shim.

Abstract

A horn-fed dish reflector antenna has characteristics including beam pattern that are a function of its mechanical form. The beam pattern can be altered by changing the mechanical configuration of the antenna. One way to do this is with a reflecting insert or shim added to the face of the original dish.

Authors:
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1088051
Report Number(s):
SAND2012-10689
456418
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English

Citation Formats

Doerry, Armin Walter. Beam spoiling a reflector antenna with conducting shim.. United States: N. p., 2012. Web. doi:10.2172/1088051.
Doerry, Armin Walter. Beam spoiling a reflector antenna with conducting shim.. United States. doi:10.2172/1088051.
Doerry, Armin Walter. Sat . "Beam spoiling a reflector antenna with conducting shim.". United States. doi:10.2172/1088051. https://www.osti.gov/servlets/purl/1088051.
@article{osti_1088051,
title = {Beam spoiling a reflector antenna with conducting shim.},
author = {Doerry, Armin Walter},
abstractNote = {A horn-fed dish reflector antenna has characteristics including beam pattern that are a function of its mechanical form. The beam pattern can be altered by changing the mechanical configuration of the antenna. One way to do this is with a reflecting insert or shim added to the face of the original dish.},
doi = {10.2172/1088051},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Dec 01 00:00:00 EST 2012},
month = {Sat Dec 01 00:00:00 EST 2012}
}

Technical Report:

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  • The report extends an earlier one dealing with the reflection coefficient approximation (RCA) for modeling objects located near an interface between electrically different half spaces. The procedure to handle objects on opposite sides of the interface is described. The method, which is denoted as the transmission coefficient approximation (TCA), is based on a ray-optics formulation and an assumed reciprocity along a given ray path. An integral-equation, moment-method technique for wires, when combined with the RCA-TCA, permits modeling the response of antennas above ground to buried objects. Similar problems of geophysical interest, as well as those of the more conventional antennamore » interface, may also be modeled. Sample results to illustrate how the technique may be applied are presented. A comparison of results is made between the RCA-TCA and those obtained from a rigorous treatment based on the Sommerfeld integrals to demonstrate the validity of the approximate approach. The approximate approach offers much greater efficiency (approximately 50 times faster) relative to the rigorous approach.« less
  • The electromagnetic field configuration generated if there is no wall surrounding the channel is investigated. An azimuthally symmetric channel of given uniform, finite, conductivity and radius is treated. It is shown that if Q is the total charge in the pulse, then the total charge that passes through any plane z > 0 is exactly equal to Q and that as the pulse moves through the channel and the distance from the ground plane to the pulse approaches infinity, the electromagnetic field configuration approaches that which results from the steady state with the same pulse moving in a channel ofmore » infinite length in the absence of a ground state. (JFP)« less
  • This report documents a series of wind tunnel tests on a sample airfoil designed to evaluate and quantify the ''pumped spoiling'' concept. The test airfoil was a Sandia National Laboratories natural laminar flow section designated SAND-1850. All tests were operated at a Reynolds Number of 1.5 million with a model having a 1-ft chord and a 9-ft span. The spoiling perforations consisted of 1.6 mm diameter holes on 6.35 mm centers. The pressure in the internal plenum that supplied the spoiling air to the perforations was maintained at the tunnel dynamic head. Test results were consistent and repeatable. Up tomore » an angle of attack of 6/sup 0/, there was very little difference in the lift coefficient among the many test arrangements studied. Past 8/sup 0/, however, the lift coefficient trends were very sensitive to the test configuration of the model. The report includes the test results for 32 combinations of the spoiling arrangements ranging from ''clean'' baseline airfoil to spoiling flow through all perforations. In addition to the section coefficients, the report presents model force data and section pressure profiles. 29 figs., 4 tabs.« less