New Radiowave Absorbers Using Magnetic Loss Caused by Metal Particles' Internal Eddy Current

A new type of radio-wave absorber is proposed which utilizes the eddy current loss of conductor particles appearing as magnetic loss of the composite material. Theoretical investigation based on a simple model suggests that the eddy current loss appears as a broad peak of μr", and the peak frequency can easily be controlled by changing the particle size. A preliminary experiment with metal composite materials showed the exsistence of the predicted magnetic lossy characteristics due to the eddy current in particles. The realizability of the wave absorber by manufactured composite material is also shown.