Feedline effects analysis of series-fed microstrip antenna array by full wave discrete image technique

A general analysis of the effects of the feedline on the radiation pattern of a series-fed microstrip antenna array is carried out using the full wave discrete image technique, which approximates the spectral Green's function by a series of complex exponential functions (images), and then inverses the Fourier transform analytically by using the Sommerfeld identity. In order to explore the effect of the feedline, a typical four-element series-fed microstrip antenna array is studied numerically and experimentally. When the leading feedline only includes one-half of a standing wave current, the radiation pattern is degraded, showing a higher sidelobe level and a wider mainlobe, as compared to the pattern where feedline effects are not present.<>