Focusing properties of leaky‐microwave from equiangular spiral slotted rectangular waveguide

Previously, the authors proposed an equiangular spiral slotted rectangular waveguide (SSW). The present paper examines various unique characteristics in the fields near the focus such as phase anomalies, focal shifts, behavior of Poynting vectors, etc., and the frequency dependency of focusing properties with respect to changes of the excitation frequency. As a result, it was found that SSW had similar various characteristics near the focus for an ordinary axisymmetric optical system. It was clarified that SSW also had additional unique asymmetric properties arising from structural asymmetry and its operation as a two‐dimensional focusing system.