A compact pattern reconfigurable antenna utilizing multiple monopoles

A reconfigurable antenna for optimal radiation patterns used for automotive urban scenarios is proposed in this paper. The antenna is anticipated to radiate in the best sub-channels obtained from a channel simulation. The antenna consist of two serially fed monopoles placed on one substrate. The pattern switching is realized by changing the phase of the feeding signal. Thus, two directional patterns are realized, whereby the first is in and opposite the driving direction and the second is shifted by 90° in azimuth, thus orthogonal to the driving direction. The chosen frequency of operation is 2.45 GHz. As a proof of concept two prototypes of the antenna, one utilizing p-i-n diodes and one using MEMS (micro-electro-machanical switch) as switching elements have been fabricated and measured. The maximum gain achieved is about 5 dBi. The measurement results show that only slight improvement is achieved if MEMS are used instead of p-i-n diodes.