A Simple Equivalent Circuit Approach for Multi-Band Polarization Converters Design

A systematic design method for multi-layer multiband linear to circular polarization converters based on classical filter theory is presented. The proposed design method uses a couple of second-order band-stop filters on each layer to create a single-band polarizer. Multiple such layers are then cascaded together to create the desired N-band response. An equivalent circuit model for the multi-layer polarizer is investigated. Equivalent circuit parameters are determined from system-level performance indicators such as the desired center frequency of operation. Circuit parameters are then related to physical parameters using closed-form equations. A design example of a dual-band polarizer for K-Ka band applications is illustrated. Anyway, the method is general and can be applied to the design of more complex configurations for N-band applications.