Comparison of medical test absorbers

Abstract

Low reflection microwave absorbers are important to improve anechoic chamber measurements. Beside used material, shape of the absorber is important as well for desired low reflection absorbers. Pyramidal and wedge type absorbers are well-known microwave absorbers used for anechoic chamber measurements. They are used as medical test absorbers for anechoic chamber measurements of medical devices as well. In this study, effect of being shape of the absorber concave or convex on reflection characteristic of the absorber is investigated. Reflection coefficient values of the convex-shaped absorber are compared with the reflection coefficient values of the concave and wedge-shaped absorbers and shown that convex-shaped absorber has better characteristics. Absorber structures are analyzed by using Periodic Moment Method (PMM). Reflection values of the absorber structures for the 2–8 GHz frequency band are compared for the normal incidence case. Their bistatic pattern comparisons are presented at 2 GHz. Analysis of an alternative absorber structure to the wedge type absorber is an important contribution of the study.