Radius Error Effect Studies of Bipolar Spherical Resonator Cavity on SLED

The bipolar spherical cavity SLED has been widely used in accelerator and high power microwave fields as it has high quality factor and is much tighter in volume than the traditional structure. However, due to its high compactness, small radius changes will lead to significant changes in the system's performance. Therefore, we study the radius error effects of the bipolar spherical resonator on SLED through theoretical analysis and numerical simulation. We conclude that if the radius of the sphere is symmetrically larger or smaller only on the axis of mode rotation, the resonant frequency of the spherical cavity will be correspondingly smaller or larger, and the change of the radius will not cause reflection. However, when the radius of the sphere changes asymmetrically perpendicular to the axis of mode rotation, the two degenerate modes will resonate at different frequencies. Due to the characteristics of the dual polarized coupler in this case, obvious reflection will appear and this could reduce the working performance of SLED seriously.