Combined pattern and frequency reconfiguration of single-element ultra-wideband monopole antenna for Cognitive Radio devices

A novel and simple frequency and pattern reconfigurable single element ultra-wideband monopole antenna realised in a compact design is presented. The antenna occupies overall dimensions of 34×31×0.88 mm³. The antenna can switch from ultra-wideband operation to narrowband operation with three different radiation pattern configurations. Three p-i-n diodes are used as switches and their package and biasing effects are included in the simulations. The simulated reflection coefficient, radiation patterns, surface current, gain and total efficiency of the ultra-wideband mode and the pattern-reconfiguration modes are presented. The compactness, simplicity and flexibility of the proposed multimode antenna meet the growing demand of Cognitive Radio devices for more intelligent and multi-functional antennas.