UWB Elliptical Monopoles With a Reconfigurable Band Notch Using MEMS Switches Actuated Without Bias Lines

Two CPW-fed elliptical monopoles were fabricated on liquid crystal polymer (LCP) with reconfigurable rejection band (band-notch) characteristics in the frequency range between 5 and 6 GHz. The first antenna uses a lambda/2 long, U-shaped slot and the second antenna uses two symmetrically placed lambda/4 long, inverted L-shaped stubs as resonating elements. Microelectromechanical system (MEMS) switches are used to activate and deactivate the resonating elements without the need of dc bias lines due to a novel design of the switch geometry. Transmission line models and surface current distributions are used to explain the effect of the added resonating elements. Reflection coefficient radiation pattern and gain measurements are presented to verify the design concepts featuring a very satisfactory performance.