Modified resonant frequency computation for tunable equilateral triangular microstrip patch

In this paper, a new closed form expression is developed to accurately estimate the resonant frequency of an equilateral triangular patch. The proposed computation is also extended to the two-layer structure in order to define the air-gap tuning effect on the resonant frequency. The theory established in this paper is compared with the experimental and theoretical results available in the literature. The results of this study show a considerable improvement achieved over the previous theories within very small percentage errors for almost all cases.