TEM horn antenna: input reflection characteristics in transmission

The reflection coefficient of open-ended, parallel-plate transmission lines of different TEM-wave impedance, Z0, have been observed using an impulsive source waveform and a sampling oscilloscope. When converted to the frequency domain the results support the theoretical analysis of mode conversion and reflection due to Weinstein. Reflection from a smoothly tapered Z0 within the feed line is also considered, showing that good pulse-optimised antennas can be designed on these two principles.