Design and measurement of a linearly dual-polarized dual-band and wideband multi-ring microstrip antenna fed by two L-probes

This paper presents design and measurement of a linearly dual-polarized dual-band and wideband multi-ring microstrip antenna fed by two L-probes. The proposed antenna consists of two circular ring patches and two L-probes arranged in a multi-layered dielectric substrate. By using a thick substrate for the L-probe and arranging two ring patches as radiation elements, the proposed antenna operates wideband and dual-band characteristics. Furthermore, by arranging two L-probes at the orthogonal positions, the proposed antenna can radiate dual linear polarizations. The measured fractional bandwidths corresponding to a reflection coefficient below -10 dB were 21.7% and 10.6% for the first and second modes, respectively. The measured isolation between two ports of the test antennas in the above bandwidths were less than -13 dB.