Synthesis and Evaluation of Nano Radar Absorbent Materials & Radar Absorbing Structures

Abstract

Electromagnetic (EM) Waves absorbing technology is one of the most valuable research areas in contemporary camouflage techniques. The synthesis, development, application and evaluation of Microwaves Absorbent Materials of various categories are investigated and discussed in this work. Microwave Absorbers have been used for both the civil and military purposes for many years. They are able to eliminate EM wave pollution and also used for microwave shielding. Nowadays, the demand for different kinds of Microwave Absorbers is on the rise in the frequency range of 1-20 GHz due to their use in Electro Magnetic Interference (EMI) Shielding. Research work is going on in the development of magnetic absorbing materials and dielectric absorbing materials utilizing magnetic loss and dielectric loss properties respectively. This project focuses on the dielectric absorbing materials as opposed to the heavy magnetic materials, which is a concerning problem. In this research we have synthesized and evaluated the composite materials for the purpose of Microwave Absorption. Ranking of different matrices was done and Carbon Black-CB nano sized particles (different weight ratios) were dispersed in epoxy resin. Subsequently, each mixture is coated onto the Aluminum plates. The Scattering parameters (S11, S21), dielectric constant and the dissipation factor of energy were measured in the frequency range 11-18 GHz, mainly by using Vector Network Analyzer. Also, sandwich composite structures were fabricated and evaluated with different core materials for the transmission purpose in the frequency range 11-18 GHz. For the experimental work, the frequency range used was 2.6-4 GHz and 11-18 GHz. With different weight percent of Carbon Black nano particles dispersed in the epoxy matrix, Dielectric RAM is synthesized. Satisfactory results are observed for Carbon Black 2% (CB2-Epoxy) combination in Ku-band. Beyond this loading, the trend reverses and it is observed that for CB3, CB4, and CB5 the attenuation level is on the decline. Few results obtained for Sandwich Composite Structures approve that they are good candidates for the transmission of EM waves.