Practical design method for an electromagnetic wave absorber at 9.45 GHz

A design chart for the fabrication of an electromagnetic wave absorber was constructed. The design chart consists of the matching boundaries, which enclose the complex permeability values satisfying |/spl Gamma/|/spl les/0.1. The area inside of the boundary represents over 20 dB attenuation. The secant method was employed to compute the matching boundary values corresponding to 20 dB attenuation. In addition to the matching boundary which is determined by the theoretical equations, several restrictions due to the fabrication process were examined. Based on the study on the effects of the variance of the thickness and permittivity on the electromagnetic wave absorbing characteristics, a means to exclude such effects was also included in the proposed design method. Among the six variables required to construct the design chart, the effect of /spl epsiv//sub r/' was investigated in the range of 5-30 at 9.45 GHz. The effect of /spl epsiv//sub r/" was not considered.< >