Design of a Compact 3D Metal Printed Ka-band Waveguide Polarizer

摘要： This letter presents design, development and characterization of compact wide band 3D printed circular waveguide based polarizer operating in Ka-band (28-34 GHz). The polarizer structure is investigated using fundamental and higher order modes and based on which a simplified equivalent structure is derived giving physical insight into its mechanism of operation. The design consists of a pair of radially opposite grooves inside a circular waveguide and excited using a coaxial probe which makes the design simple and highly compact as compared to other conventional circular polarizers. The design is compared with other existing waveguide based polarizers in terms of electrical and physical parameters. Fabrication is done using high resolution direct metal aluminum 3D metal printing. The measured axial ratio is better than 3 dB over the frequency band. The design simplicity makes it attractive for application in millimeter wave frequencies and beyond.