Development of a Modified Hilbert Curve Fractal Antenna for Multiband Applications

This paper presents the development of a Modified Hilbert Curve Fractal (MHCF) antenna with parasitic patches for multiband applications. The fractal antenna has been designed on a dual-layer substrate having a dimension of 50 x 60 x 3 mm simultaneously fed by a modified coplanar waveguide (CPW) feed. The geometry of the step feed has been optimized using swarm intelligence-based Dragonfly Optimization (DO) technique to enhance the bandwidth. The antenna offers multiband resonating characteristics with a bandwidth of 0.315 GHz (0.68-0.99 GHz), 3.220 GHz (3.98-7.20 GHz), 2.955 GHz (8.043-10.998 GHz) and 1.94 GHz (12.7-14.64 GHz). The proposed antenna indicates a higher degree of impedance matching with a stable omnidirectional radiation pattern at all resonating frequencies. The reported antenna has been fabricated and tested for the validation of resonating and radiation characteristics. Simulated and measured results are found in good agreement with each other. The fractal antenna is useful for radiolocation in Ultra High Frequency (UHF) band and for aeronautical radionavigation service (ARNS) in C-band, X-band and Ku-band as defined by International Telecommunication Union (ITU).