Experimental evaluation of the Hybrid Smart Antenna system with directional array elements

Abstract

The Hybrid Smart Antenna Algorithm (HSAA) relies on elimination of the array elements with the smallest received signal powers in the beamforming process in order to improve the computational efficiency, and reduce the hardware cost. Earlier computer simulations [1] suggested that it is possible to further suppress the sidelobes by employing directive array elements. In this paper we present the results of experimental verification of this observation. Specifically, an 8-element array consisting of 30°half power beamwidth (HPBW) Yagi-Uda antennas is used with the HSAA. Although the directivity of the array elements is heavily affected by the mutual coupling effects, a significant decrease in the sidelobe levels is observed thus confIrming the simulation results. This experimental effort further confIrmed other advantages of the HSAA approach. It is shown that the exact direction of arrival (DOA) is determined by selecting only 2 elements out of the 8 possible with the Yagi-Uda elements while the array of omni-directional dipole elements required at least 5 out of 8 elements. The experimental procedure is described and comparison with simulation results is presented. I. INTRODUCTIONBy sampling the transmitted signal several times in space, and coherently combining them, smart antenna receiver systems provide extended communication ranges, higher data rates, and larger capacities. As expected, the number of elements in the array is the main determinant of the smart antenna system performance, and there is a linear relationship between the quality of the smart antenna system performance and the number of elements on the array. However, the computational complexity of the array increases with the second power of the number of array elements in addition to the linear increase in the hardware cost [1].

Mutual coupling compensation for a practical VHF/UHF Yagi‐Uda antenna array

“…All the aforementioned literature were about the antenna array with omnidirectional antennas. Recently, Celik et al [22], have experimentally evaluated the performance of a smart antenna system with directional elements. Their effort confirmed the advantage of Yagi-Uda antennas to omnidirectional ones in DOA estimation of impinging signals.…”