Four arms star: An useful geometry for switchable FSS

In this paper, the four arms star geometry is proposed as a basic FSS element. The design of the proposed geometry is described and simulated results obtained using the Method of Moments are presented. When compared to the conventional rectangular patch, the four arms star FSS presented a considerable reduction of the first frequency of resonance and values about 50% can be achieve without further optimizations. In addition, the proposed geometry is useful to switchable FSS, because the switch point is limited to a small area, which can avoid undesirable effects, such as parasitic capacitances. The ON-OFF switch states were ideally simulated and the well-defined ON-OFF switch states were observed. In order to validate the numerical results, three FSS were selected, fabricated and experimentally characterized. For each one, the ON-OFF switch state was considered. The obtained experimental results present a very good agreement when compared to simulated ones and confirm the expected frequency behavior. The four arms star FSS performance become very attractive to many applications in modern communications systems, especially smart antennas.