A Combined Right Hand Circular and Linear Polarisation Antenna For GPS and Cellular Telephone Usage

O.P. Leisten

Abstract:	The paper shall chart the continued development of the miniature dielectric loaded volute antenna topology that was the subject of a paper presented at ION-9.5’. It will give an account of development of the topology since that time with an emphasis on empirical verification. This review of progress shall lead to a conceptual explanation of the operation of a dual mode antenna which supports two resonant modes. The antenna comprises an upper radiating section with a straight helical loop and a meandered helical loop that are respectively disposed at right angles and phased so that they support a cardiod right hand circular polarisation pattern when excited with balanced currents. The lower portion of the antenna is a mode-manager and trap element which facilitates an alternative single- ended mode of resonance in which currents pass down the helices in phase synchronism and into the guiding region of the trap. In this mode of resonance the antenna acts as a current fed inverted monopole. It is possible to dimension the element so that the right- hand circularly polarised and vertically polarised modes are respectively positioned at the GPS Ll and 820-900MHz US cell-phone frequency allocations. An example of an antenna element design functioning as a dual-mode GPYcellular antenna in this mode is described together with the design of a typical automotive diplexer component which separates the GPS and cellular signals. Finally, the use of the antenna is considered, as part of a tight integration of GPS and cellular phone circuits, to implement mobile telephone appliances with positioning facilities.
Published in:	Proceedings of the 9th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1996) September 17 - 20, 1996 Kansas City, MO
Pages:	1763 - 1769
Cite this article:	Leisten, O.P., "A Combined Right Hand Circular and Linear Polarisation Antenna For GPS and Cellular Telephone Usage," Proceedings of the 9th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1996), Kansas City, MO, September 1996, pp. 1763-1769.
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