A Planar Pattern-Reconfigurable Antenna With Stable Radiation Performance
Shengnan Zhao, Zhan Wang, Yuandan Dong
Abstract
In this letter, a planar antenna withreconfigurable radiation pattern is investigated for smart Wi-Fi systems. The design incorporates one pair of folded dipoles, a microstrip-to-via feeding balun and two reconfigurable parasitic strips which are near-field excited by the dipole pair. By controlling the states of two Pin diodes embedded in two reconfigurable printed lines, the proposed antenna can switch between one omnidirectional mode and two unidirectional endfire radiation modes. This optimized antenna exhibits a decent size of 0.5 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.38 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.004 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is free space wavelength at 2.45 GHz). Good agreement is observed between the simulated and measured results. The overlapped impedance bandwidth 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 for the three pattern modes is from 2.34 to 2.6 GHz in the measurement. Throughout the overlapping bandwidth, the front-to-back ratios are higher than 15 dB for the two unidirectional radiation modes and out-of-roundness is less than 1.2 dB for omnidirectional radiation mode. The measured peak realized gain of the proposed pattern-reconfigurable antenna is 6 dBi. This proposed Wi-Fi antenna is well poised for intelligent Wi-Fi communication systems.