Flexible Super Wideband Antenna for Microwave Imaging Applications

In this study, a Coplanar Waveguide (CPW)-fed flexible super-wideband antenna is designed and analyzed in free space and cylindrical bend. Polyimide was used as the substrate material. A dielectric constant (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\epsilon_{r}$</tex>) of 3.5 and height (h) of 0.135 mm were considered. The CPW-fed flexible superwideband antenna resonates at 19.38 and 30.84 GHz when placed in free space and at 16.38 and 33.02 GHz when bent cylindrically. The reflection coefficients (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{S}_{11}$</tex>) were -33.90 dB and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-37.27 \mathbf{d B}$</tex> for free space and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-51.74 \mathbf{d B}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-62.33 \mathbf{d B}$</tex> for the cylindrical bend. The bandwidth was observed as 44.21 GHz (15.11 to 59.33 GHz) for free space with gains of 7.82 dBi and 8.82 dBi, respectively. For the cylindrical bend, the bandwidth was observed as 47.47 GHz (13.75 to 61.22 GHZ) with gains of 2.24 dBi and 4.08 dBi, respectively. The CST v2019 software was used to design and simulate the proposed antenna. According to the design analysis, the proposed antenna is suitable for Microwave Imaging applications.