Broadside-coupled slot-line field components

Expressions for the odd- and even-mode electric field components and for the magnetic field components in the dielectric and air regions of a suspended broadside-coupled slot-line with an overlay (Simons, 1982) are presented. It is assumed that the dielectric substrate and the overlays are isotropic and homogeneous and are of arbitrary thickness and relative permittivity. It is further assumed that the conducting cover and the zero-thicknes metallization on the substrate have infinite conductivity. These expressions are computed numerically at various points in the dielectric region and the air regions of the structure. The odd- and even-mode magnetic field in the longitudinal section through the slot are discussed. Also illustrated are the current distribution on the metal surfaces and the magnetic field tangential to the metal surfaces. Consideration is also given to a slot-line with a lower ground plane. The current paths on the lower ground plane and the magnetic field tangential to the lower ground plane are described.