Beam steering for circular switched parasitic arrays using a combinational approach
- Authors: Mofolo, Mofolo R. O. , Lysko, Albert A. , Olwal, Thomas O. , Clarke, Willem A.
- Date: 2011
- Subjects: Antenna radiation patterns , Circular switched parasitic arrays , Electronic beam steering
- Type: Article
- Identifier: uj:6090 , ISSN 978-1-61284-992-8 , http://hdl.handle.net/10210/10949
- Description: In this paper we present a method of electronic beam steering for circular switched parasitic array (SPA) antennas. In circular SPA antennas, one achieves azimuth beam steering by open-circuiting and short-circuiting different parasitic elements, usually with only one parasitic element open-circuited at a time. For the SPA antenna with few parasitic elements, this results in low azimuth beam steering resolution. In the proposed method, we iterate through different combinations of parasitic elements and the possible switch states of the lumped impedance loads connected to the parasitic elements. Our method aims to increase the azimuth beam steering resolution of the circular SPA antennas. The method is verified using a combination of simulation (using both MATLAB and WIPL-D) and a SPA antenna prototype implementation. The MATLAB code uses the induced EMF method, while the WIPL-D uses the Methods of Moment (MoM) for solving the antenna impedances. The three sets of results (simulations and measurement) match very well at 2.4 GHz. The results indicate the availability of more options (different loading configurations) for electronic beam switching that can be adopted to improve the beam steering resolution of circular SPA antennas.
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Method of electronic beam steering for circular switched parasitic dipole arrays
- Authors: Mofolo, M. , Lysko, A. , Clarke, W.
- Date: 2010
- Subjects: Switched parasitic arrays , Electronic beam steering
- Type: Article
- Identifier: uj:6088 , http://hdl.handle.net/10210/10943
- Description: This paper presents a method of electronic beam steering for a smart antenna system based on a switched parasitic array. The antenna system is made up of circular array of half wave dipoles, with four parasitic elements positioned equidistantly, surrounding one active central element. All parasitic elements are assumed to be switched between short-circuit and opencircuit states to change their resonant length. The switching between parasitic elements’ states is attained by connecting a switch that assumes ON/OFF states at the centre of each parasitic element. This allows some parasitic elements to act as reflectors while shortcircuited, whereas other parasitic elements act as directors when open-circuited. Thus, the direction of maximum gain is controlled by open- and shortcircuiting the parasitic elements. By appropriately selecting correct combination of short- and opencircuited parasitic elements together with the active element, a set of radiation patterns is formed covering the horizontal plane. Results for the horizontal coverage are presented with the main beam(s) directed at 00, 900, 1800, and/or 2700, as well as for an omnidirectional configuration resemblance. It is expected that increasing the number of parasitic elements will improve directional properties further.
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