Optimisation of thin microwave absorbers and the effect on bandwidth

The approach described is based on optimising the design of Salisbury Screen type absorbers by varying the dielectric constant of the spacer and the resistance and lumped capacitance (as arrays of discs) of the interleaving sheets. The method used has been to optimise the design parameters to obtain specified input impedances at a number of frequencies. A series of simultaneous equations are set up, two for each frequency relating the real and imaginary parts of the impedance to the required values. An example of these equations is shown