Reconfigurable single-feed antennas for diversity wireless communications

Antenna arrays are used in wireless communications to combat multipath fading by exploiting the spatial diversity of the multipath channel. Often only two antenna elements are used, since larger arrays require a complex feed structure and possibly more power amplifiers (PAs) and low-noise amplifiers (LNAs). An alternative to a more standard antenna array with one or multiple corporate feeds is a single-feed electronically reconfigurable antenna combined with an oversampling receiver. Such an antenna can exploit the diversity offered by a multipath channel by switching the radiation pattern. We present a reconfigurable one port multiply excited (OPOMEX) antenna array along with simulations of the resulting diversity gain. We show that this approach offers more than 14 dB of diversity gain at an error probability of 10^-4. This improvement is less than that of a standard dipole array of equivalent aperture size, but the OPOMEX antenna contains a single simple feed and requires a single LNA for reception. The paper discusses the tradeoffs involved in using the reconfigurable OPOMEX antenna to exploit spatial diversity in a wireless communication system.