Calculation of external aperture admittance and radiation pattern of a narrow slot cut across an edge of a sectoral cylinder in terms of a spectrum of two-dimensional solutions

A slotted triangular cylinder is a candidate for a base station antenna in mobile communications. This paper presents an analysis of the external aperture admittance and the radiation pattern of a transverse narrow slot cut across one of the wedges of a sectoral cylinder, the cross section of which approximates the actual triangular shape. Thereby, the external region can be described in terms of two canonical shapes, for which the dyadic Green´s functions are obtained analytically. The aperture admittance of the slot is expressed in terms of the integrals of magnetic current over the slot aperture and the infinitely extended interface of the canonical regions. These integrals are evaluated in the spacial and spectral domains, respectively. This hybrid analysis provides good convergence of the results. The dependence of the 3-dB beamwidth and the front to back ratio of the transverse radiation pattern from the slot upon the size and the sector angle of the cylinder are also presented