The design and analysis of a Ka-band coaxial to waveguide transition

The main objective of this paper is to design and analyze a Ka-band coaxial to waveguide transition which is an indispensable component in a satellite payload system, providing the microwave signal transfer from coaxial to waveguide or vice verse. We analyze a Ka-band coaxial to waveguide transition based on the FDTD method used by Nabarro (see IEEE Trans. Microwave Theory Tech. vol.42, p.347-50, 1994 and IEE Proc., vol.142, no.6, p.495-7, 1995). In order to simulate a real situation and to analyze the characteristics of a transition accurately, a coaxial cable is modeled by cylindrical cells, a rectangular waveguide is modeled by rectangular cells, and the connecting part between two structures are analyzed using the interpolation scheme which is based on the first order Taylor series approximation and coordinate transformation. The s-parameters and input impedances of a transition using the present approach are compared with those of HFSS and measurement.