In this article, a triple-band wearable monopole antenna fed by a coplanar waveguide (CPW) with an integrated electromagnetic bandgap (EBG) array is proposed. The monopole antenna consists of an asymmetric inverted U-shaped strip, a horizontal branch, and an L-shaped ground stub, which can generate the 2.45/5.8 GHz wireless local area network (WLAN) band and the 3.5 GHz worldwide interoperability for microwave access (WiMAX) band. To reduce the influence of antenna radiation on the human body, a triple-band 3 × 3 EBG array has been integrated into the back of the monopole antenna. The EBG unit is composed of two rectangular rings and a circular ring, and the operating frequencies correspond to the triple bands of the monopole antenna. In this paper, the impedance and radiation performances of the stand-alone monopole antenna and the integrated antenna are analyzed, and the safety for the human body is evaluated based on specific absorption rate (SAR) values. The proposed triple-band antenna can be used in wearable devices in wireless body area networks (WBANs).

The investigation of how to control the microwave scattering from strong scattering sources has vital applications in military and civilian areas. As a typical target, a rightangle dihedral corner reflector has been extensively investigated because of its strong electromagnetic scattering over a wide observation angle range. In this paper, a right-angle dihedral corner reflector with three loading conditions of the camouflage grass described in our previous investigation is discussed to investigate the radar cross section (RCS) reduction effect for the typical target. For different RCS reduction effects of the camouflage grass loading conditions, which include paste, cover and shield, the calculated results and the measurement results are presented and compared. The loading of camouflage grass greatly reduces the RCS of the corner reflector over a wide angle range at 10 GHz and a broad band from 4 GHz to 18 GHz. The paste loading condition of camouflage grass achieves the best RCS reduction effect. Then, the difference in the monostatic RCS curves is analyzed and explained by multiple scattering effects. The advantages of employing camouflage grass lie in its ability to clearly reduce the RCS of the dihedral corner reflector without shaping the targets or use absorbing materials.

In this work, the complex electromagnetic model of a camouflage grass was accurately generated in geometry, of which the grass leaves were represented by lathy curved rectangular metal surfaces. To investigate the electromagnetic scattering characteristics of the camouflage grass model in the radar band, its radar cross section (RCS) from 4 GHz to 18 GHz was calculated by multilevel fast multipole method (MLFMM). For validation, the camouflage grass sample was manufactured and measured. A relatively good agreement was observed between the results of the calculation and the measurement. Based on this modeling and calculation method, the electromagnetic scattering characteristics of camouflage grass with different leaf lengths, widths, and densities were investigated. According to the numerical results of the application examples, the electromagnetic scattering characteristics changed regularly with the variation of the leaf parameters, and these results were analyzed by electromagnetic wave scattering and phase cancellation. This model will help with the radar camouflage experimental design and electromagnetic scattering investigation of camouflage grass.

To reduce the lightness and enhance the thermal resistance of Al-pigmented low-emissivity coatings, CuCr₂O₄ pigment was introduced into the coating system via ball milling. The results revealed that both ball milling time and Al: CuCr₂O₄ mass ratio significantly affect the optical and infrared properties of the coatings. When the milling time reached 9 h, the pigment attained an optimal flake morphology, leading to the best infrared performance of the composite coating. Additionally, the CuCr₂O₄ content effectively suppressed the lightness of Al-pigmented coatings. Compared to Al-pigmented low-emissivity coatings, the composite coating with an Al:CuCr₂O₄ ratio of 10:2 exhibited a reduction in L* value from 90 to 65. Meanwhile, it retained a low average infrared emissivity of 0.42 in the 3–5 μm and 8–14 μm ranges. Moreover, the incorporation of CuCr₂O₄ significantly improved the Al-pigmented coating’s thermal resistance from 500 °C to 600 °C. The composite coating maintained a Grade 1 adhesion rating with heat treatment of 600 °C due to a self-healing effect_. These composite coatings with low emissivity, low lightness, and high-temperature resistance are highly suitable for high-temperature and infrared stealth applications.

This paper proposes a fast iterative solution method for accurately analyzing the electromagnetic scattering of honeycomb using the global generalized product-type bi-conjugate gradient stabilized with l parameter (GPBICGSTAB(l)) algorithm combined with the Thin Dielectric Sheet (TDS) method. In the global GPBICGSTAB(l) algorithm, a polynomial H(λ) with L+1 terms is introduced to accelerate the update of induced currents during the iteration process, thereby enabling the rapid solution of the Method of Moments (MOM) matrix equations. The accuracy of the proposed algorithm is validated by comparing its calculated Radar Cross Section (RCS) results with both the FEKO calculation results and the measured data of a honeycomb physical model. Compared with the recycling BICGSTAB for solving impedance matrix equations, the proposed algorithm reduces the number of convergence iterations by 46%, effectively improving convergence efficiency. Additionally, the algorithm demonstrates significant optimization in computational time, achieving a reduction of up to 60%.