The Anglet: An E/H-plane Bent, 90-Degree Twisted, TE101/TM110-Mode Singlet Building Block

In this work, a subclass of the singlet building block is defined. Termed the anglet, a waveguide cavity-based structure is demonstrated that combines a bend, a 90-degree polarization rotation, and produces one pole and one transmission zero. The anglet is defined due to its unique ability to be viewed as either a TE
101
-mode singlet or a TM
110
-mode singlet based on the users coordinate point of view together with the requirements for the bend direction and polarization rotation. Two types of anglets are demonstrated by simulation and a third-order filter is demonstrated for the incorporation of an anglet in a practical design. Emphasis on its unique capabilities are highlighted due to its nature as a fundamental-mode resonator with evanescent bypass coupling. Furthermore, an accurate approximation for the source-load coupling is described and a prototype filter is fabricated and measured in order to validate the concept.