Performance Evaluation of Automatic Switched-Beam Antennas for Indoor WLAN Systems

In this paper, the design of a compact low cost switched-beam antenna for users in Wireless Local Area Networks (WLAN) is introduced. Four antenna elements are arranged in 2×2 lattice. The modification of beamforming network based on Butler matrix is originally proposed for 2×2 planar array. The design is verified through computer simulations and also the prototype of automatic switched-beam antenna is constructed to confirm its performance. Moreover, the validation of performance enhancement is investigated through the signal strength measurements at the users operating in existing WLAN infrastructure. The results confirm the advantage of switched-beam antenna employing modified Butler matrix by improving signal strength with average power of 4.37 dB over the use of omni-directional antenna. Key-words: Antenna arrays, Beamforming, Butler matrix, Measurement, Signal strength, WLAN