Triangular microstrip antenna is commonly used in wireless communication. Several approximate formulae for its design are in use. This paper presents a new design formulae for equilateral triangular patch antenna. This is based on Bhatnagar's Postulate. The postulate is extended and validated for equilateral triangular patch antenna. Thus a new thinking for estimating physical side length of a triangular microstrip antenna has been presented. The 'H' concept has been used here to put forward a new formula for estimating the physical side length of the triangular patch. It has been postulated that “Extension in physical side length of the patch is directly proportional to the
normalized thickness of the antenna substrate and the electrical side length of the patch. The constant of proportionality is independent of the resonant frequency, thickness and Dielectric
Constant of the substrate”. For a triangular patch also its value is unity.