A beamforming method for a reactively steered adaptive array antenna with RF-MEMS device

An adaptive array antenna is an antenna that controls its own antenna pattern by means of feedback or feedforward control. Paying our attention to its application for terminals in WLAN (wireless local area networks), analog adaptive array antennas, such as RESAA (reactively steered adaptive array) antenna and phased array antenna, are advantageous and attractive in terms of cost and power consumption. Especially, with recent remarkable advance in MEMS (microelectromechanical system) technology, RF (radiofrequency)-MEMS implemented power- and bandwidth-efficient analog devices, such as inductors, capacitors and varactors, have been available. Therefore, the analog adaptive array antenna with RF-MEMS device at the wireless terminal side is promising in the future WLAN, however, a special beamforming method is required taking into consideration its response and characteristic. This paper proposes a new beamforming method taking into consideration the mechanical structure of the beam control device. Here, we assume a RESAA as an example of analog array antenna and the OFDM (orthogonal frequency division multiplexing)-based IEEE 802.11a standard as a system model.