Improved Evaluation of Sommerfeld Integrals for Microstrip Antenna Problems

An improved technique for accurate evaluation of the Sommerfeld integrals appearing in the Gzx component single layer microstrip Green´s function is described here that utilizes closed-form evaluation of the infinite tail, and numerical integration of a finite integral. The overall method avoids: (a) any pole calculations, and, (b) the traditional large argument approximation of the Bessel function of the Sommerfeld integrand. Initial numerical results from this proposed method are included. Since the method avoids any pole calculations, it can be expected to provide improvement for full-wave analysis of a wider class of microstrip patches on electrically thick substrates.