Analysis of a printed grid array antenna by a fast MoM calculation technique

An integral equation for an arbitrarily shaped printed wire antenna has been derived and solved with the help of the method of moments (MoM). So far, zigzag dipole, loop, and spiral antennas have been analyzed using this integral equation. Conventionally, the MoM impedance matrix element Z_m,n is composed of four terms g_{m-1, n-1}, g_{m-1, n}, g_{m, n-1}, and g_{m, n} each involving a triple integral and requiring a long time to compute. This paper presents a new representation of the MoM impedance matrix element, which drastically reduces the computation time, compared with the time required using the conventional impedance element. The new representation is based on a technique for decomposition of the Green´s functions, each function being decomposed into a weighted free-space Green´s function term and a perturbation term. The decomposition yields a new MoM impedance matrix element, Z^NEW,_{m, n}, which is composed of three terms, Z^ψS_{m, n}, and Z^ψ_{m, n}, and ΔZ_{m, n}, involving single, double, and triple integrals, respectively. Obviously, the calculation of the new impedance matrix element Z^NEW_{m, n}, is simpler than that of the conventional impedance matrix element Z_{m, n}, resulting in a reduction in computation time