Aerospace Defense

Abstract Microstrip open-loop resonator filters are one of the most important structures used in the design of microwave and RF filters. These resonators, which are actually rectangular or square rings with a gap, are widely used in telecommunication systems such as cellular, satellite and radar systems due to their desirable characteristics. Among the advantages of these filters are miniaturization, low losses, flexibility in design, easy fabrication and low cost. In this paper, a 5th order microstrip open-loop filter with a Chebyshev architecture and a center frequency of 1300 MHz and a bandwidth of 200 MHz is presented, with the distances between the resonators optimized by the ant colony algorithm (). In this study, an open-loop microstrip filter with dimensions of one-half the wavelength was designed by the ant colony algorithm and improved the S11 parameter by at least 5 dB in the passband.

Abstract The design of Urban Air Mobility (UAM) vehicles faces numerous challenges during the conceptual phase and subsystem integration due to their multidisciplinary nature and technical complexities. To address these challenges, this study presents a systems engineering framework based on the V-Model for a fixed-wing air taxi. The primary innovation of this approach lies in establishing a structured development process that ensures full Requirements Traceability Matrix (RTM) through continuous verification and validation at each stage, thereby reducing the risk of non-compliance with initial requirements by 40% .To evaluate efficacy, the performance of this model was compared against a traditional design method. In the traditional approach, engineering disciplines such as aerodynamics and propulsion are optimized sequentially with limited integration. This disjointed approach often leads to sub-optimal system-level performance due to the neglect of key interdisciplinary couplings. Numerical results from this comparison demonstrate that the design based on the V-Model achieved a flight endurance of 89 minutes (56% improvement), a range of 95 km (55.4% improvement), and a 35.6% reduction in cruise power consumption. Furthermore, this approach resulted in an 8.0% reduction in final weight and a 25.9% saving in manufacturing costs. These findings prove the effectiveness of the V-Model as a powerful framework for the optimal and reliable development of complex aerial systems.

Abstract In this study, the performance of anticorrosion coatings was evaluated through an integrated approach combining standards analysis, IRIA F operational data, and aircraft case studies. The results of potentiodynamic polarization and EIS tests in a 3.5 wt.% sodium chloride solution showed that the epoxy coating containing mandarin peel extract achieved protection efficiencies of 94% and 93% for aluminum alloys 2024 and 7075, respectively. Microscopic analyses and FTIR confirmed the stability of the coating, while MD simulations revealed the inhibitor adsorption mechanism. Based on these findings, practical guidelines were proposed for inspection, application of anticorrosion coatings, and optimization of storage conditions to enhance aircraft service life and operational readiness.

Abstract Electromagnetic absorbers operating within the X band play a critical role in reducing wave reflection, improving impedance matching, and enhancing the performance of radar systems In this study, a three-layer structure consisting of a surface Graphene/Epoxy layer, a porous CNT/Epoxy core, and an aluminum backing plate with a total thickness of 7 mm was designed and evaluated using a dual approach framework: numerical simulation in COMSOL Multiphysics and analytical modeling based on classical electromagnetic theories.

The numerical results indicate that the reflection loss reaches approximately −18.8 dB (corresponding to 98% absorption) around 9 GHz, whereas the analytical model predicts a peak value of −21 dB at the same frequency. Both methods show closely matched trends within the 8–12 GHz band, with deviations becoming more pronounced at the band edges and remaining below 10% near the resonance region. Impedance analysis reveals that minimizing the mismatch between the real part of the effective impedance and the free space value is the primary factor responsible for the reduced reflection at resonance. Furthermore, the geometric sensitivity analysis shows that increasing the thickness of the surface layer shifts the absorption peak toward approximately 8.5 GHz, while increasing the core thickness moves it toward around 9.5 GHz. These findings demonstrate that precise control over the geometry, thickness, and material parameters of each layer enables effective tuning of the frequency response and optimization of the absorber’s performance.

Abstract In this work, nanostructured copper selenide (CuSe) thin films were fabricated using a simple solution‑based chemical bath deposition method, which is attractive due to its low cost, readily available precursors, and scalability for potential aerospace sensing applications. In the chemical bath deposition process, growth parameters play a crucial role in determining the physical and electronic properties of the final product. In addition to the concentration of selenium ions, the complexing agent is a key factor affecting film formation and properties. The complexing agent controls the release rate of metal ions in the solution and consequently influences the stoichiometry and electronic structure of the deposited films. It was observed that variations in the concentration of the complexing agent significantly modify the band gap energy .Specifically, increasing the concentration of the complexing agent leads to a reduction in the band gap energy. This behavior can be attributed to the corresponding increase in the effective concentration of free copper ions in the solution, which alters the growth mechanism and electronic structure of CuSe thin films. Therefore, the complexing agent, through its influence on the concentration of metal ions during deposition, plays a fundamental role in tuning the band gap energy, which is important for optimizing these thin films for aerospace sensing applications