Graphene/styrene-isoprene-styrene copolymer composite thin film as a flexible microstrip antenna for heptane vapors detection

The electronic devices use mainly copper based microstripantenna for communication between each portable device in a network. Inmany fields of science, graphene is one of the most promising material.Gradually, there are... [ view full abstract ]

The electronic devices use mainly copper based microstripantenna for communication between each portable device in a network. Inmany fields of science, graphene is one of the most promising material.Gradually, there are increasing possibilities for the use of graphene inelectronics. The main reasons for employing this material are its characteristics,which are, for instance, the good electrical conductivity or great potentialfor miniaturization.

This contribution is focused on the use of polymer composite containing graphene as a filler for the application materialized in a passiveantenna. This device consists of a layer of particulargraphene/styrene-isoprene-styrene copolymer composite deposited on PET foilsubstrate. To make the antenna, the graphene/styrene-isoprene-styrene copolymer dispersion was prepared by sonicationof the polymer toluene solution and after that dip-coated on the PET foil substrate(25 % by wt. of graphene particles). The thickness of electrically conductivecomposite film active layer was 0.58 mm while of the PET foil 0.21 mm. The prepared microstrip antenna(width 10, length 25 mm) operates at frequency 1.8 GHz (-40.02 dB). The measurement set up is schematicallydemonstrated in Fig. 1. The main advantage of the antenna is its low weight andflexibility. This antenna was finally exposed to saturated vapors of heptane at 25°C. Heptane is a solvent for the styrene-isoprene-styrene copolymer leadingto the composite film swelling. The swelling caused volume changes of thepolymer layer as well as a change of its macroscopic electrical resistance. Consequently,also the antenna parameters were changed such as the gain in decibels and the shiftof resonant frequency. It suggests, that the made polymer composite based thin film flexiblemicrostrip antenna can be used for heptane vapor detection.

This work was supported by the Ministryof Education, Youth and Sports of the Czech Republic – Program NPU I (LO1504)and with the support of the Operational Program Research and Development forInnovations co-funded by the European Regional Development Fund (ERDF) and the nationalbudget of the Czech Republic, within the framework of the projectCPS-strengthening research capacity (reg. number: CZ.1.05/2.1.00/19.0409).