CPW-fed body worn monopole antenna on magneto-dielectric substrate in C-band

Abstract

Body worn antennas generally face the problem of isolation when operated in close proximity to human body. Use of magneto-dielectric material as substrate for antenna makes the system compact and reduces the influence of body on performance of antenna. In addition, miniaturization of antenna size also takes place. 7 wt.% of nano-sized Ni0.5Zn0.5Fe2O4 is dispersed as magnetic filler in flexible linear low density polyethylene matrix. Beyond 7 wt.%, the sample stiffens and loses flexibility because of percolation limit of the polymer. Verification of the composite as a potential substrate for a body worn antenna is carried out by fabricating a coplanar waveguide fed simple rectangular monopole antenna, using transmission line model at 6 GHz. Antenna performance is studied by wearing the patch on human wrist. S11 of −21.78 dB at 5.32 GHz and −10 dB bandwidth of 49.62% is observed. For comparison, an antenna at the same resonant frequency is developed on linear low density polyethylene with magnetic inclusions. The antenna on magneto-dielectric substrate shows better performance than dielectric substrate. The magnetic and dielectric properties of the Nickel Zinc Ferrite-linear low density polyethylene composite magneto-dielectric substrate reduces the influence of the human body which makes the antenna system compact and robust as additional techniques are not required for shielding of human body influence on antenna performance.