Dual-port spidron fractal slot antenna for multiband gap-filler applications

A novel dual-port Spidron fractal slot antenna has been developed for multiband gap-filler applications. The proposed antenna consists of a Spidron fractal slot, two microstrip feeding lines, and a conducting reflector. Two microstrip feeders are used to excite the Spidron fractal slot antenna at the 2.5 GHz and 5.5 GHz frequency bands. The proposed antenna was fabricated and tested. The fabricated antenna has dimensions of 55 mm$\,\times \,$55 mm$\,\times \,$18 mm. The measured $-10~{\rm dB}$ reflection bandwidths for the lower and upper frequency bands were 25% (2.28-2.93 GHz) and 19% (4.87-5.89 GHz), respectively. Although microstrip feeders share a single Spidron fractal slot, a low coupling level of less than $-18.4~{\rm dB}$ was achieved. The measured peak gains of the antenna were 5.64 dBi to 6.78 dBi at the lower band and 6.71 dBi to 8.22 dBi at the upper band.