Miniaturized Planar Pattern-Reconfigurable Antenna for Smart Wi-Fi Applications
Jiawen You, Yuandan Dong
Abstract
A single-layer planar printed antenna with four endfire unidirectional patterns is proposed. The antenna consists of four reconfigurable electric dipoles and two combined Z-shaped strips as a magnetic dipole printed on the upper and lower surfaces of the substrate. Four directional radiation modes are achieved by switching the PIN diodes to excite different electric dipoles. Based on the Huygens principle, the endfire directional patterns with a high front-to-back (F/B) ratio and wide beamwidth covering the entire azimuthal plane in four states are obtained. The fabricated antenna features a compact size of 0.33λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.33λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.016λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> represents the free space wavelength at 2.45 GHz). A prototype operating at 2.4 GHz WLAN band (2.40–2.48 GHz) was fabricated and tested. The measured bandwidth achieves 7.3% (2.36–2.54 GHz) and 5.0% (2.36–2.48 GHz) with | <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | < −10 dB and F/B ratio >15 dB, respectively. The measured peak gain and radiation efficiency of the proposed endfire pattern diversity antenna are higher than 3.20 dBi and 72% in the operating frequency band. The proposed antenna is well-suitable for space-limited intelligent Wi-Fi communication systems.