Miniature Multi-Element Antenna for Wireless Communications

We present a novel broad-band miniature antenna and employ it in a multi-element geometry with diversity capabilities for wireless communications. This antenna (diameter 0.2 and thickness 0.06 ) consists of two stacked circular patches that create two cylindrical slots resonating at two slightly different frequencies, fed by a strategically positioned coaxial probe. An extensive parametric study and results for a prototype working at 5.2 GHz are presented. A multi-element geometry with two or four of such elements follows. Microelectromechanical system (MEMS)-based switches located within its geometry can not only change the working frequency of the design, but also activate a particular radiation beam depending on their specific location (resonant slot-aperture or feed line). Simulation results of a four-element antenna with dimensions 0 8 0 8 0 06 and a frequency band operation from 5 to 6 GHz are presented and compared to an experimental prototype. Circuit and radiation characteristics are discussed in terms of reconfigurability and diversity capabilities.