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http://hdl.handle.net/2289/6418| Title: | A Wideband Resistive Beam-Splitter screen |
| Authors: | Mahesh, Nivedita Subrahmanyan, Ravi Udaya Shankar, N. Raghunathan, A. |
| Keywords: | Radio interferometry Mathematical model, Antenna measurements |
| Issue Date: | Nov-2015 |
| Publisher: | IEEE |
| Citation: | IEEE Transactions on antennas and propagation, 2015, Vo. 63, p4835 |
| Abstract: | We present the design, construction, and measurements of the electromagnetic performance of a wideband space beam splitter. The beam splitter is a sheet in free space that is designed to divide incident radiation into reflected and transmitted components for interferometer measurement of spectral features in the mean cosmic radio background. Analysis of a two-element interferometer configuration with a vertical beam splitter between a pair of antennas leads to the requirement that the beam splitter be a resistive sheet with sheet resistance ηo/2, where ηo is the impedance of free space. The transmission and reflection properties of such a sheet are computed for normal and oblique incidences and for orthogonal polarizations of the incident electric field. We have constructed such an electromagnetic beam splitter as a square-soldered grid of resistors of value 180 Ohms (approximately ηo/2) and a grid size of 0.1 m. We measured the reflection and transmission coefficients over a wide frequency range between 50 and 250 MHz in which the wavelength well exceeds the mesh size. Measurements of the coefficients for voltage transmission and reflection agree to within 5% with physical optics modeling of the wave propagation, which takes into account edge diffraction.i |
| Description: | Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations) |
| URI: | http://hdl.handle.net/2289/6418 |
| ISSN: | 0018-926X 1558-2221 (Online) |
| Alternative Location: | http://adsabs.harvard.edu/abs/2015ITAP...63.4835M http://arxiv.org/abs/1406.2585 http://dx.doi.org/10.1109/TAP.2015.2478443 |
| Copyright: | 2013 IEEE |
| Appears in Collections: | Research Papers (A&A) |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 2015_IEEETrasAnt&Prop_63_4835.pdf Restricted Access | Restricted Access | 1.31 MB | Adobe PDF | View/Open Request a copy |
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