Airplane tail scatter analysis and tail notch calculation

A UGTD analysis has provided predictions of the fields scattered by the vertical stabilizer of the tail of a commercial passenger transport airplane, when illuminated by a fuselage- mounted Ku-band satcom antenna. The predicted scattered fields allow the worst case increase in sidelobe levels relative to the regulatory off-axis mask to be determined, and used as a design metric. Analysis of typical test cases has shown that by applying a -15dB maximum tail illumination criterion, the sidelobe increase, relative to the regulatory off-axis mask, is acceptably constrained. Finally this design criterion allows the angular dimensions of a trapezoidal transmit-muting "tail notch" to be rapidly calculated, using knowledge only of the antenna patterns.