Microstrip patch antenna as a paper moisture sensor

Abstract This paper reports the use of non destructive, microstrip patch antenna as moisture sensor. Microstrip is designed to resonate at 2.4GHz. design simulated and fabricated on copper clad type FR4 (εr= 4.4) having thickness 1.6mm. Patch dimension are 27mm × 30mm substrate 63mm 60mm. The transmission line used provide excitation for antenna. after fabrication showed a resonance 2.38 GHz vector network analyzer S11=-19.38dB with impedance =49Ω. variations in frequency relation water content measured using Vector Network Analyzer by placing wet Moisture was found out taking weight dry paper. model recommended primarily basis water-dry reactions, along surface roughness explaining tendencies sensitivity graphs. Paper samples 13 different types, GSM values thicknesses, havingdimensions same that were tested. From results it observed increases decreases. change respect seen have quadratic moisture. fitted form equations. calculated %Mwet indicates an error around ±0-4% value compared actual value. response sensor almost linear references but coefficients depend non-linearly dimension.