Design of One Kind of Multilayer Microstrip Antenna Working at Dual-frequency and Treble-polarized

Two electromagnetic signals which have orthogonal both phase and space can generated one circular polarized (CP) signal, in the opposite hand, one CP signal can separates into two lineal polarized signals. One kind of strip fed multilayer microstrip antenna using cross-slot coupling is discussed in this paper. Constructed of one right-hand-circular polarized (RHCP) and one left-hand-circular polarized (LHCP) antenna cell, an antenna array is designed out in this paper. By choosing appropriate feeding circuit, the antenna array is designed to work at dual-frequency on 12.75 Ghz and 14 Ghz, fed separately by three dividedly ports, it can radiate vertical, horizontal, 45deg to horizon lineal polarized signals separately. The according PCB to this design worked well at this very dual-frequency.