A reconfigurable wide band phased array antenna for generating multiple antenna beams for multiple transmit and receive functions. The antenna array comprises multiple long non-resonant TEM slot antenna apertures with RF MEMS switches disposed within the slots. The RF MEMS switches are positioned directly within the feed lines across the slots to directly control the coupling of RF energy to the slots. Multiple RF MEMS switches are used within each slot, which allows multiple transmit/receive functions and/or multiple frequencies to be supported by each slot. The frequency coverage provided by the slot antenna has a greater than 10:1 frequency range.