The nonuniformline matching was achieved by forming the TEM horn plates into
empirically determined tear-drop shapes. A small resistance-card
termination was placed at the tip of the aperture to provide adequate
current attenuation for a traveling wave. With these empirical
modifications, the length of the TEM horn was reduced to 0.33λ with
a reasonable reflection coefficient for the frequency range of 100 MHz
to 2 GHz