Equivalent radius analytic formulas of Substrate Integrated Cylindrical Cavity

Equivalent radius of a Substrate Integrated Cylindrical Cavity (SICC) is an important parameter for calculating the resonant frequency and designing a SICC device. In this paper, based on two sets of equivalent width analytic formulas of Substrate Integrated Waveguide (SIW), the equivalent radius analytic formulas of SICC were derived by the conformal transformation method for the first time. In order to verify the validity of these formulas, using the formulas given in this paper calculated the equivalent radii and the corresponding resonant frequencies of TM₀₁₀ mode SICCs, and the resonant frequencies of TM₀₁₀ mode SICCs were also calculated by the method introduced in [12] and simulated by electromagnetic simulation software. The results show that the formulas given in this paper have higher precision, and are convenient, suitable to more application fields, so they will play important role in the analysis and design of SICC devices.