Integrated Polarization Converter for Planar Cross-Polarized Millimeter Wave Components
In the millimeter wave (mmW) band, it is possible to excite signals in printed circuit boards or PCB where the electric field is parallel to the plane of substrate and bounded by the upper and lower conducting layers of the PCB. Based on this concept, dually polarized mmW components have been developed recently to double the capacity of those components. The integration of dually polarized and conventional single polarized components on one substrate creates a significant bottleneck. The solution for this bottleneck is the design of an integrated polarization converter which fully rotates the horizontally polarized field. This rotation converts the horizontal field to be vertical to be easily fed to the rest of the circuit with minimum loss. The polarization conversion is achieved by artificially induced skew anisotropy, which is realized by drilling tilted holes in the conventional isotropic substrate. This theoretical concept for polarization conversion is developed in this paper. The design procedures along with a simulation example are presented. Fabrication methodologies and different variations of prototypes are discussed.