A Planar Four-Port Integrated UWB and NB Antenna System for CR in 3.1GHz to 10.6GHz

This paper is aimed to present a planar four-port integrated UWB and narrowband (NB) antenna system for cognitive radio (CR) technology in the UWB 3.1GHz to 10.6GHz. This system consists of a UWB antenna for spectrum monitoring and three NB antennas for communication. These ultra wideband and narrowband antennas are incorporated on an FR-4 substrate having dimensions $\pmb{28}\mathbf{mm}\pmb{\times31}\mathbf{mm}\pmb{\times1.6}\mathbf{mm}$ , The ultra wideband antenna, attached to port 1, is capable of monitoring the complete FCC unlicensed UWB spectrum 3.1GHz to 10.6GHz. The three NB antennas accomplish either single or dual bands to access the complete 3.1GHz to 10.6GHz band for communication. In particular, the first narrowband antenna, linked at port 2, attains a single band ranging from 8.26GHz to 11.16GHz. The second narrowband antenna, allied at port 3, also yields a single operating band ranges from 4.29GHz to 6GHz. The third NB antenna, associated with port 4, achieves a dual band behaviour starting from 3.06GHz to 4.49GHz and 5.97GHz to 8.35GHz. The coupling between the antennas is less than -17dB across the complete UWB. The proposed antenna system is fabricated and tested. It is observed that there is a good agreement between the simulated and measured results.