Compact size cognitive radio with non- and uni-planar parasitic coupled section for UWB and WLAN/WiMax application

Due to the requirements of increased bandwidth and data transfer rate in wireless communication, cognitive radio (CR) has been proposed as a solution to the spectrum scarcity problem. Regarding the many advantages that ultra-wideband (UWB) antennas offer, they could be used in CR systems. Simultaneously, by designing a band reject filter for avoiding interference with other applications, like wireless local area network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX), safety communication can be provided. In this work, two novel CRs (so that secondary ports are as non-planar and uni-planar parasitic antennas shapes) are presented. Each antenna consists of two ports at the opposite sides; one of them plays as UWB port (first work: 3.1-10.6 GHz and second work: 2.98-11.83 GHz) with filtered WLAN/WiMAX (first work: 4.9-5.8 GHz and second work: 4.9-6.08 GHz) and the other one supports filtered frequency bandwidth (first work: 4.8-6.2 GHz and second work: 5.1-6 GHz). Size reduction occurred in this work with both structures having the same size of 25 x 25 x 0.8 mm(3). The designed antennas were measured and results of antennas have agreed well with the simulation analysis.