An analytical model is presented to improve the performance of the equilateral triangular microstrip antenna (ETMA). An improved model is presented taking into account the insertion of an air gap between the substrate and the ground plane, and High Tc superconducting material (HTS) for the triangular patch. The full-wave spectral domain technique in conjunction with the complex resistive boundary condition is used to calculate the characteristics including resonant frequencies, bandwidths, and radiation efficiency. Numerical results for the air gap tuning effect on the operating frequency and bandwidth of the high Tc superconducting triangular microstrip antenna (HTSTMA) are presented. The effect of temperature on resonant frequency and bandwidth of the HTSTMA are also given. The computed data are found to be in good agreement with results obtained using other methods.