Cavity model analysis of 30°-60°-90° triangular microstrip antenna

Modal analysis of probe fed 30°-60°-90° triangular microstrip antenna (TMA) is presented using cavity model for TMz mode. Probe excitation is modeled here in three simple ways. A comparative study among these three types of feed modeling is given in a systematic way, hitherto unreported. Input impedance, quality factor, radiation patterns, efficiency, gain are discussed for first five modes. Closed form expressions for calculating the far-field radiation patterns are given here for the first time. New broadside modes are identified and excited successfully, hitherto unreported. Theoretical results are in good agreement with measured data and/or data obtained using 3D EM simulator. It is found that all first five modes show a peak in broadside direction. The results should be useful for practical design of 30°-60°-90° TMA.