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.
