Elementary patterns for conformal dipole arrays mounted in dielectrically clad conducting cylinders

The elementary pattern is derived for a conformal dipole array printed on the surface of a thin dielectric sheet covering a large-radius conducting cylinder. The dimension of the array in the cylinder axial direction is infinite. Two-dimensional Green's functions for a single dipole column are evaluated in the near zone of the cylinder using the Watson transform method. The poles of a Green's function are traced on a complex plane using perturbation techniques. As the beam of the dipole column is lifted off the horizontal plane towards the axial direction, a new set of poles emerge as a result of the coupling between TM and TE modes with respect to the cylinder axial direction. Since the emerging dominant pole as the elevation beam angle increases from zero is nearly real, a resonance inside the dielectric sheet can be generated in an array environment. Because of the resonance phenomenon, the elementary pattern cut at an elevation angle undergoes significant changes from the horizontal plane pattern.