Attempt has been made to synthesize polyaniline-carbon fiber (PANI-CF) composite via in-situ emulsion polymerization using beta-naphthalene sulphonic acid (NSA) which acts as both surfactant as well as dopant. Free standing PANI-CF thin sheets are prepared which have electrical conductivity similar to 1.02 S/cm with improved mechanical strength and thermal stability. The scanning electron microscopy is used to study the surface morphology of the composites. Structural characterization is done by using XRD. The dielectric attributes (epsilon* = epsilon' - i epsilon '') of PANI-CF sheets are calculated using experimental S parameters (S-11, S-12) by Nicolson Ross Wier equations. It has been demonstrated that these sheets show maximum shielding effectiveness (SE) of 31.9 dB at 12.4 GHz frequency at a thickness of 1.5 mm. Free standing PANI-CF sheets so prepared have a potential for X-band microwave absorber application. (C) 2015 Elsevier B.V. All rights reserved.