A Ku-Band Compact Wideband Tri-Polarized Antenna with Low Cross Polarization

A Ku-band compact wideband tri-polarized antenna is proposed. The antenna consists of the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 45^{\circ}$</tex> dualpolarized ring-shaped dipoles and the vertical distributed monopole. A simple feed structure formed by metallized vias is proposed to solve the feeding problem of the compact dualpolarization dipoles. Meanwhile, Y-shaped coupling lines and V-shaped parasitic strips are adopted to expand bandwidth for dipoles. The distributed monopole is fed by a four-ways power division network and its bandwidth is expanded through loading the feeding vias of dipoles. Simple feed forms and functional multiplexing of feed structures between different polarizations result in a compact and symmetric tri-polarized antenna with the size of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.45\lambda_{0}\times 0.45\lambda_{0}\times 0.23\lambda_0$</tex>. The simulated results indicate the tri-polarized antenna has an overlap bandwidth of 28.7%, the port isolation greater than 30dB and the cross polarization less than -28dB in operating bandwidth, which can be applied in satellite systems to improve communication performances.