A Compact Dual-Element Uniplanar Antenna for Portable Broadband MIMO Systems

A printed dual-port coplanar waveguide (CPW)-fed antenna is proposed for wideband communication systems. The antenna includes two identical hybrid trapezoidal-elliptical radiating elements that are printed perpendicular to each other. Also, two orthogonal CPW lines are used to feed the antenna. In order to achieve broadband dual-polarized operation with a compact size, the geometrical parameters of the antenna are optimized by using Ansoft HFSS. The antenna was fabricated and tested. Reasonable agreement between the simulation and experimental results is obtained. The fabricated prototype with a small size of 25 x 53 mm(2) can cover the wide operating frequency band from 2.4 to 18GHz (reflection coefficient less than -10 dB) for both ports. The measured isolation is better than 25 dB over the entire operating bandwidth. Moreover, the measured results show that the proposed antenna can provide omnidirectional radiation patterns with a good orthogonal polarization operation, reasonable gain, high radiation efficiency, and constant group delay.