Chaotic patterned absorber design

In this thesis, a comprehensive study on the design, simulation, fabrication, and experimental validation of ultra-wideband microwave absorbers based on various chaotic systems is presented. Inspired by the complexity and irregularity inherent in nonlinear dynamical systems, chaotic attractors have been systematically investigated to generate unique resonator patterns. These patterns were transformed into two-dimensional fractal structures using the Julia Fractal system, and the chaotic patterns processed through the Gaussian filtering method were fabricated by screen-printing with HSF-54 resistive ink onto an FR-4 substrate. As a result of these processes, the chaotic-patterned microwave absorber structures exhibited high absorption rates exceeding 90% within the 2–20 GHz frequency range. A series of parametric analyses were conducted on substrate thickness, unit cell dimensions, incidence angle, material conductivity, and polarization modes (TE, TM, and TEM). The findings revealed that the fabricated chaotic-patterned microwave absorbers possess strong angular stability and polarization independence. Comparative studies among different chaotic systems highlighted that optimized configurations demonstrated near-perfect absorption with minimal reflection, emphasizing the electromagnetic advantages of nonlinear dynamics in absorber performance. To examine the accuracy of the simulation results, various measurements were performed using a VNA, and the fabricated chaotic-patterned absorbers were experimentally analyzed. The experimentally obtained scattering parameters (S-parameters) and absorption rates were found to be in good agreement with the simulation results. This study introduces a new methodology for absorber design, offering new advantages in fields such as Defense, Healthcare, Communication, EMI shielding, and intelligent electromagnetic surface development. The research demonstrates that chaos patterns derived from various chaotic attractors can serve as a powerful tool for next-generation adaptive and highly efficient microwave absorbers.