A Switched-beam Antenna Using Circumfere- Ntial-slots on a Concentric Sectoral Cylin- Drical Cavity Excited by Coupling Slots

This paper presents a switched-beam antenna using circumferential-slot on a concentric sectoral cylindrical cavity excited by coupling slots to operate at 5.8 GHz. The advantages of this antenna are conformal structure, high directivity and capable of switched-beam pattern in six directions. The antenna design starts from a single sector which is capable of switching between radiating and non-radiating modes. The L-shaped coupling slots are proposed to accommodate the switching circuit. Each RF switch is made of two PIN diodes connected in a reverse series connection and placed across the slot at the appropriate location. Subsequently, the exciting probe is designed for matching TM01 mode of the circular waveguide. The measured results of the proposed antenna give a gain of 7 dBi and |S11| less than −20 dB at 5.8 GHz. This antenna is suitable for base station applications that require the switched-beam pattern in the azimuthal plane. Received 22 July 2011, Accepted 25 August 2011, Scheduled 1 September 2011 * Corresponding author: Denchai Worasawate ([email protected]). 128 Wounchoum et al.