Polarizer based on waveguide with complex cross-section

Waveguide transducers of linear polarization waves to the circular ones are widely used in microwave engineering. The concept of such devices is based on the decomposition of an initial linearly polarized wave into two orthogonal components and obtaining the 90° phase shift between them in the polarizer output. Many ways of implementation of this concept are known, the most common way is an insertion of lumped or longitudinal discontinuities into a regular circular or square waveguide.