RF MEMS Reconfigurable Two-Band Antenna

The design methodology, analysis, and characterization of a radio frequency microelectromechanical systems (RF MEMS)-based reconfigurable antenna operating in the United States Public Safety bands are presented. It has two modes of operation with central frequencies of 718 and 4960 MHz, providing a high reconfigurable frequency ratio of <formula formulatype="inline"> <tex Notation="TeX">$\sim {7}$</tex></formula>. This antenna is electrically small with lateral dimensions being <formula formulatype="inline"><tex Notation="TeX">$\sim \lambda/10 \times \lambda/10$</tex></formula> at 718 MHz. The reconfigurability between the modes is achieved by a single RF MEMS switch, which enables changing the length of the current flow path, thereby the resonance frequency is changed. The measurement results for impedance and radiation characteristics of the fabricated antenna prototype agree well with the simulations. The measured bandwidths of the antenna are 2.6% and 7.6% at 718 and 4960 MHz, respectively.