Electromagnetic and absorption properties of carbonyl iron/rubber radar absorbing materials

• Published in: IEEE transactions on magnetics Vol. 42; no. 3; pp. 363 - 368
• Main Authors: Yong-Bao Feng, Yong-Bao Feng, Tai Qiu, Tai Qiu, Chun-Ying Shen, Chun-Ying Shen, Xiao-Yun Li, Xiao-Yun Li
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.03.2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Absorption; Carbonyl iron; Carbonyls; Cross-disciplinary physics: materials science; rheology; Dielectric materials; Electromagnetic wave absorption; Exact sciences and technology; Frequency; Iron; Magnetic materials; Magnetism; Materials science; Mathematical analysis; Organic materials; Other topics in materials science; Permeability; Permittivity; Physics; Radar; radar absorbing material (RAM); Random access memory; Reflection; reflection loss; Rubber; Volume fraction; reflection loss; Absorption; Magnetic permeability; Carbonyl iron; radar absorbing material (RAM); permeability; Rubbers; Magnetic materials; Permittivity; Magnetic properties
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2005.862763

We measured the effective complex magnetic permeability /spl mu//sub eff//sup */ and dielectric permittivity /spl epsiv//sub eff//sup */ spectra in rubber radar absorbing material (RAM) with various carbonyl iron volume fractions by using the transmission/reflection method with a vector network analyzer. We studied the effects of carbonyl iron content and rubber thickness on the microwave absorption properties in the frequency range of 2.6 to 18 GHz. Our mathematical analysis is based on electromagnetic theory. The results indicate that the effective complex magnetic permeability and dielectric permittivity values of the RAM increase as the carbonyl iron volume fraction increases. For sample thickness of 3.0 mm, an increase in carbonyl iron content reduces the minimum reflection loss from -1.3 to -23.9 dB and shifts the frequency of the minimum reflection loss from 15.5 to 3.5 GHz. For an equal volume fraction of carbonyl iron, the frequency of the minimum reflection loss decreases as the thickness is increased. However, the dip in the reflection loss plot (in decibels) initially decreases to a minimum value before it increases with a further increase in thickness. We determined the value of the reflection loss for the samples by the impedance matching degree (reflection coefficient), which depends on the thickness and composition of the RAM.