A low-profile antenna is proposed in this letter for realizing dual polarizations with omnidirectional radiation patterns. Vertical polarization is obtained by a modified annular ring slot antenna, and horizontal polarization is obtained by a modified printed arc dipole array. By combining the ground plane of the ring slot antenna and the dipole array on the same layer, the profile of the antenna is reduced to minimum extent. The proposed prototype has a low profile of 0.024λ0 (λ0 is the free-space wavelength at 2.4 GHz). To verify the design, the proposed antenna is fabricated and measured. Measured reflection coefficients, isolation, and radiation patterns results agree well with the simulated data. The common band of vertical and horizontal polarizations makes the proposed antenna satisfy the WLAN diversity systems with omnidirectional characteristic.
2. Astely, D., E. Dahlman, A. Furuskar, Y. Jading, M. Lindstrom, and S. Parkvall, "LTE: The evolution of mobile broadband," IEEE Communications Magazine, Vol. 47, No. 4, 44-51, Apr. 2009.
3. Vaughan, R. G., "Polarization diversity in mobile communications," IEEE Transactions on Vehicular Technology, Vol. 39, No. 3, 177-186, Aug. 1990.
4. Li, Y., Z. Zhang, J. Zheng, and Z. Feng, "Compact azimuthal omnidirectional dual-polarized antenna using highly isolated colocated slots," IEEE Transactions on Antennas and Propagation, Vol. 60, No. 9, 4037-4045, Sept. 2012.
5. Li, Y., Z. Zhang, Z. Feng, and M. F. Iskander, "Design of omnidirectional dual-polarized antenna in slender and low-profile column," IEEE Transactions on Antennas and Propagation, Vol. 62, No. 4, 2323-2326, Apr. 2014.
6. Dai, X. W., Z. Y. Wang, C. H. Liang, X. Chen, and L. T. Wang, "Multiband and dual-polarized omnidirectional antenna for 2G/3G/LTE application," IEEE Antennas and Wireless Propagation Letters, Vol. 12, 1492-1495, 2013.
7. Guo, D., K. He, Y. Zhang, and M. Song, "A multiband dual-polarized omnidirectional antenna for indoor wireless communication systems," IEEE Antennas and Wireless Propagation Letters, No. 99, 2016.
8. Quan, X. and R. Li, "A broadband dual-polarized omnidirectional antenna for base stations," IEEE Transactions on Antennas and Propagation, Vol. 61, No. 2, 943-947, Feb. 2013.
9. Huang, H., Y. Liu, and S. Gong, "Broadband dual-polarized omnidirectional antenna for 2G/3G/LTE/WiFi applications ," IEEE Antennas and Wireless Propagation Letters, Vol. 15, 576-579, 2016.