Performance of a Miniature Dielectrically Loaded Volute Antenna

Oliver Leisten and Geraint Ffoulkes-Jones

Abstract:	This paper describes the design and predicted characteristics of a miniature dielectrically loaded quadrifilar helix antenna which is 5mm in diameter and approximately 20mm long. The antenna is considerably foreshortened with respect to its equivalent dimensions in air by the use of a Zirconium Tintinate ceramic dielectric core. The Zirconium Tintinate material used is produced by Morgan Matroc Ltd as a high stability microwave ceramic dielectric material and possesses a relative dielectric constant (E,) of 36. The intention is to provide a quadrifilar antenna of small physical size which should possess excellent phase centre stability and also low angle discrimination that is superior to that of the conventional microstrip patch antennas. The antenna element is realised on a rod section of ceramic material with a co-axial feed passing axially, through the centre of the rod to the feed connection point at the top surface. the base portion of the antenna is formed into a metallised sleeved balun which creates the conditions for the required balanced feed at the top feed point. This base section also serves as a convenient metal surface to solder to a circuit board or alternatively as a clamping surface for incorporation into a mechanical assembly. The radiating section consists of two loop pairs which are respectively fed from the individual inputs comprising the balanced pair of feeds. Each loop pair consists, in clockwise order, of a helix element that is 45 degrees short, followed by a helix element that is 45 degrees longer than half a wavelength at the operating frequency. This feed scheme creates the necessary orthogonality (at the radiation resistive normalisation impedance). The antenna element is small and light enough to be incorporated as tips into communication whip aerials.
Published in:	Proceedings of the 8th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1995) September 12 - 15, 1995 Palm Springs, CA
Pages:	869 - 877
Cite this article:	Leisten, Oliver, Ffoulkes-Jones, Geraint, "Performance of a Miniature Dielectrically Loaded Volute Antenna," Proceedings of the 8th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1995), Palm Springs, CA, September 1995, pp. 869-877.
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