A linearly polarized dual-resonant millimeter-wave absorber for Radio Detection And Ranging (RADAR)applications is presented in this paper. The frequency-selective absorber (FSA) is composed of solitarily using the distributed elements. The proposed FSA achieves a dual-band resonance characteristic utilizing the mutual coupling between concentric square loops, the second harmonic mode of the Jerusalem cross, and the corrugated cross grids. The proposed dual-band FSA operates from 25.5 to 26.5 GHz (1 GHz) (fL) and 31.8 GHz–32.5 GHz (0.7 GHz) (fH) with minimum absorptivity of 96% and 92%, respectively. The desired frequency response of the proposed unit cell is demonstrated by an equivalent circuit model. The FSA prototype is fabricated and the simulated results are validated using experimental measurements. The proposed FSA is a suitable candidate for stealth application in defense and military systems.

To obtain the optimal solution for the performance of the turbofan engine using infrared stealth technology, an engine mathematical model with a backward infrared radiation intensity calculation module was established. The effects of infrared suppression measures on the performance of turbofan engines were analysed. Based on the multi-objective particle swarm optimisation (MOPSO) algorithm, the optimal solution for the performance in the cruise state of the reference engine refitted with the infrared radiation suppression module was obtained; Further, through the multiple design points (MDPs) concept, the thermal cycle optimisation design of the turbofan engine was carried out. The results show that the integrated fully shielded guiding strut (IFSGS) with air film cooling had the ideal infrared suppression effect. Compared with the reference engine refitted with infrared radiation suppression module, the engine after cycle optimisation design could obtain better infrared stealth performance.

The ever-changing battlefield environment, as well as the emergence of global command and control architectures currently used by armed forces around the globe, requires the use of robust and adaptive technologies integrated into a reliable platform. Unmanned Combat Aerial Vehicles (UCAVs) aim to integrate such advanced technologies while also increasing the tactical capabilities of combat aircraft. This paper provides a summary of the technical and operational design challenges specific to UCAVs, focusing on high-performance, and stealth designs. After a brief historical overview, the main technology demonstrator programmes currently under development are presented. The key technologies affecting UCAV design are identified and discussed. Finally, this paper briefly presents the main issues related to airworthiness, navigation, and ethical concerns behind UAV/UCAV operations.

The Great War ushered in a new era of long-distance combat. For the first time, weapons with a very long range were massively deployed, in previously unheard-of places: under the sea and in the air. Stealth fighting also included espionage and propaganda, now orchestrated on a global scale. In reaction to the carnage in the trenches, a degree of moral rehabilitation came to be conferred on the weapons initially associated with a “cowards’ war”. This in turn encouraged experimentation with the new, unmanned technology that would lead to the first prototypes of guided munitions and drones.