Input impedance of a coaxial line probe feeding a circular waveguide in the TM/sub 01/ mode

By means of the conversion of complex power technique (CCPT), a formally exact full-wave solution is given for the case of a coaxial line probe fending a circular waveguide for TM/sub 01/ modal excitation. The overall scattering matrix of the coaxial-line-prove-circular-waveguide system is deduced. Numerical results for the impedance as 'seen' by the coaxial line are presented and compared with experimental results obtained in the 9.0-11.5-GHz frequency range. Their agreement is reasonably good except at the lower frequencies (<10.0 GHz), where the TM/sub 01/ mode in the circular guide is close to its cutoff frequency (8.14 GHz).<>