Design and Fabrication of Microstrip Patch Antenna on Flexible Epoxy Substrate Material

This paper deals with the fabrication and characterisation of microstrip patch antenna on a flexible substrate. The flexible planar antenna finds wide applications in defence, satellite, medical and automobile industries. Now days it is the most researched topics across the world. The flexible antenna gets conformal to the surface and can be used across curved surfaces. An antenna using room temperature vulcanizing silicone rubber compound is used as substrate on which the patch antenna is fabricated. Patch size was chosen such that the antenna resonates at 4.5 GHz. The substrate material used was characterised for its dielectric properties using Vector network analyzer (VNA). The resonant frequency does not show variation when the antenna is folded up to an angle of 30° from its centre feed location. The antenna with measured substrate properties was also simulated in High Frequency Structure Simulator (HFSS). Measured results for resonance frequency are in close approximation with that of simulated one. Slight variation in resonant frequency may be due to finite ground plane dimensions and variation of feed location. Silicone compound offers the flexibility of adding magnetic materials to alter the dielectric and magnetic properties, resulting in further miniaturisation. The simulation and measured results suggest that flexible substrate antenna can be successfully used for miniaturisation and with curved surfaces.