Design and analysis of effective graded microwave absorbing material for low observable technology

Compositional designing of effective graded radar absorbing material for low observable technology is always a challengeable task in material science. The micro scale or quantum scale interaction of electromagnetic radiation is depends on the characteristic property of each atom or their assembly in a material composition. The filler and matrix in a composite structure plays a vital role between the advantages in electromagnetic absorption capability and the disadvantage due to difficulties in practical homogenous dispersion with weight concentration. The present work describes synthesis of biomaterial based effective graded radar absorbing material (RAM) for application in stealth technology. Ultrasonic treated rice husk raw material shows a significant increase of dielectric property of the composite material blended with epoxy resin. The significant modification in surface of the biomaterials with ultrasonic wave provides the enhanced mechanical strength as well as hardness of the material. Bio ceramic material composed of china clay and carbon rich waste rice husk ash possesses good dielectric loss for frequency 10 GHz and reflection loss -24.5 dB which is quite significant for stealth technology. Scanning electron microscopy (SEM) study shows good dispersion of rice husk ash in the epoxy matrix. Frequency dependence of both dielectric constant and dielectric loss are measured in the X band frequency range (8.2-12.4 GHz). This low cost laboratory scale synthesized RAM find its application in designing of stealth aircraft and jet fighter for military purposes. (author)