With the increasing radio communications activities of recent years, the radio spectrum is becoming intensely crowded and this trend is set to increase at an extraordinary rate. Radio astronomy is particularly sensitive to interference of this type. A high temperature superconducting (HTS) filter, at the front-end of the receiver, has the potential to effectively eliminate the interference from adjacent bands. Such a filter will have negligible loss, have extremely sharp filter skirts and be small enough to fit into the current low temperature systems. HTS microwave filters started to emerge during the early 1990s, and since then much effort has been put into filter designs for narrow band applications. However, there are still not many wide band HTS filters reported. Here we are interested in a wide band filter for radio astronomy applications. Four HTS microstrip filters have been designed according to the specification from Jodrell Bank Radio Observatory. Among them, a nine-pole Chebyshev HTS wideband filter has been fabricated and tested. Good agreement between simulated and experimental results has been obtained. The filter has also been tested in Jodrell Bank radio astronomy. The telescope receiver system test showed that the HTS filter contributed negligible noise to one of the receiving channels when compared to the other channel without an HTS filter. The prototype filter is to be used on the Lovell Telescope in Jodrell Bank Observatory.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:560819 |
| Date | January 2004 |
| Creators | Li, Yuanzhi |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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