Wideband Dual-Polarized Antenna For Spectrum Monitoring Systems

An antenna merging inverted-cone monopole and cross bow-tie dipole are presented for achieving dual polarizations while maintaining a wide bandwidth. The proposed design consists of an inverted-cone hollow tube, a small circular ground, and a cross bow-tie dipole with a conductor ring. The invertedcone monopole is fed by a 50-Ω N-type connector to realize a vertical polarization (VP). The cross bow-tie dipole is excited by a broadband feeding network to achieve a horizontal polarization (HP). More importantly, the cross bow-tie dipole not only serves as the radiating element for the HP, but also acts as the ground plane for the inverted-cone monopole. Additionally, the antenna can achieve omnidirectional radiation patterns in particular frequency band for VP and HP, respectively. Simulated results show that the inverted-cone monopole achieves a wide-impedance bandwidth (for |S11| <; -10 dB) from 190 to 850 MHz, and the cross bow-tie dipole realizes a wide operating bandwidth from 80 to 880 MHz. A prototype of the proposed antenna is fabricated and tested. Measured results are in good agreement with simulated ones.