Figure 3: An admittance plot for a two-layer design. The starting point at real admittance 1.5 is defined by the properties of the uncoated substrate. The larger the distance from real admittance 1 on the real axis, the higher the reflectance. The design should travel in clockwise arcs and arrive at point (1, 0), jumping from one material locus to another (starting a new layer) as needed.