CORNER EFFECTS ON THE MUTUAL IMPEDANCE BETWEEN EDGE SLOTS

An analysis for calculating the mutual impedance between two edge slot s in a linear slotted waveguide array is presented. The analysis uses a 90-degrees wedge Green function to account for the influence of the waveguide corners on the evaluation of the external mutual coupling. A novel asymptotic formula for the 90-degrees wedge Green function is d erived to expedite the numerical analysis for slots with large separat ion. Numerical results show that the phase of mutual impedance retards linearly with slot separation and the magnitude decays as the separat ion is increased. However, the mutual impedance of edge slots is large r and decays more slowly than that of longitudinal slots or other slot s in a large ground plane. The distinguished characteristics can be at tributed to the energy guiding effect of the waveguide corners, which is discovered and verified mathematically and numerically. Also shown in the numerical calculations are the incremental conductances of the individual slots in a linear edge slot array, which are compared, and found to be in good agreement, with the available experimental data.