Abstract
The modal-expansion method is employed to analyze an array of multiple
monopole antennas. A perfectly conducting plate is introduced at the top of the monopole
array to facilitate the modal-expansion analysis. Expansion coefficients in the field
expressions are found by enforcing continuity conditions of the tangential field components
across the regional surfaces. Cylindrical function's addition theorem is employed to realize
the transformation of field expressions in different coordinate systems. Numerical results for
the