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A Compact Tri-port Antenna System for Cognitive Radio Applications

In this paper, a compact and low-profile tri-port antenna system is proposed for cognitive radio (CR) applications. The proposed system consists of a ultra-wide band (UWB) antenna fed by co-planar waveguide (CPW) structure and two meandered monopole antennas on the same substrate. The spectrum sensing is performed by UWB antenna (3.1 GHz - 10.1 GHz) and meandered antennas operates in several frequency bands for communication purpose. Without any decoupling structure the isolation level between UWB and meandered antennas is higher than 15 dB in the UWB frequency range. The measured S-parameters and radiation patterns are in good agreement with simulation results.