International Symposium on Antennas and Propagation
Using Hybrid Ring Coupler to Form Butler Matrix of Switched Beam Antenna Array System for Wireless Communication Products
Ching-Jen Chang, Hsin-Piao Lin, Shiann-Shiun Jeng,
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Switched beam Antenna array is a kind of smart antenna system, wherein an appropriate radiation pattern to transmit and receive signals can be selected. The structure switched beam antenna array system implemented in this paper contains an antenna array and a feed network composed by the 4*4 Butler matrix. Here, one wavelength of hybrid ring coupler will replace the original Butler matrix structures formed by branches of coupling devices, to undergo implementations and measurements. Because hybrid ring couplers may replace Butler matrix, its allocation of positions along the circuit is quicker. On the antenna array implementation, this paper uses four omni-direction antennas with distances of half a wavelength from each other to form an antenna array with linear arrangement. This coordinates with the hybrid ring Butler matrix feed network. The measured four beam directions obtained from realistic implementations matches the simulated ideal omni-directional radiation pattern of the antenna array. Hence, the antenna array implementation method this paper proposes can serve as a reference for future applications of switched beam systems on wireless communication products.