Sensitivity analysis of a circularly polarized U-slot microstrip antenna

In this paper, sensitivity models for centre frequency and maximum radiated power of a rectangular microstrip antenna at φ = 0 plane using Effective Length Theory have been developed. A wide operating bandwidth for a single-layer coaxially fed microstrip antenna is obtained by cutting a U shaped slot on the metal patch. The sensitivity of perturbation of different truncated slot and feed position for a microstrip antenna is a novel concept. An approximate sensitivity model is derived here using perturbation and variational method and confirmed by modified Haneishi model and hybrid FEM/MoM solver. The proposed sensitivity models provide better approximations for calculating shift of centre frequency and maximum radiated power of the microstrip antenna.