Coaxial to rectangular waveguide transitions

The transition between coaxial line and rectangular waveguide has been extensively studied in the past. The probe antenna usually a cylinder, is the extension of the inner conductor of the coaxial line into the waveguide normal to the H-plane. Several models for the probe geometry and current distribution are considered, both for open- and short-circuited antennas. In the case of shorted antenna, a two-stage analysis is employed. In the first stage, the coaxial line is matched to the reduced-size waveguide followed by the second stage which involves the design of an impedance transformer. The mode matching method is used to solve this part of the problem, which helps obtain more accurate results than those obtained by classical approximate methods.<>