Aero-Structural Coupling Strategy for a Morphing Blade Cascade Study

The coupling of aerodynamics and structural mechanics is an important step in the design process of aeronautical devices with morphing parts. In this paper, a 2D-3D coupling approach is developed to study a morphing blade cascade. Two shape memory alloy actuators are placed on the upper and lower sides of the blade to make possible the change in shape of the leading-edge. In the present work, a preliminary design study is conducted by considering a two-dimensional CFD analysis of an airfoil cascade coupled with a three-dimensional structural analysis of the whole 3D blade. A methodology is developed to match 2D and 3D meshes such that the aerodynamic loads can be easily transferred to the structural analysis. From there, the deformed blade geometry due to both aerodynamic loads and actuator work can be transferred back to the CFD solver, and the iterative aero-structural coupling loop can be repeated until convergence. The aero-structural coupling strategy developed in this work is also applied to a blade cascade study aiming to improve its performance by morphing the leading-edge of the blade. The results of this application show that by morphing the leading-edge blade of only few millimeters (less than 2 mm), it is possible to achieve a relevant performance improvement in terms of total pressure loss coefficient decrease of about 53%.

A New Washable UHF RFID Tag: Design, Fabrication, and Assessment

This paper deals with the design and fabrication of durable radio frequency identification (RFID) passive tag with inductive coupling, operating at ultra-high frequencies, dedicated to the identification and monitoring of professional textile products. A reliable architecture for the tag transponder is proposed, featuring a minimal number of galvanic contacts: The two pins of the integrated circuit are connected to the terminals of the inductive coupling loop by using surface mount technology welding. The transponder is encapsulated with an electrically insulating material which is waterproof and resistant to mechanical, thermal, and chemical stress. The antenna is inductively coupled to the transponder through a double loop which substantially reduces the length of the tag and significantly improves the coupling factor, enabling the tag to operate at a low power level. The reliability and flexibility of the tag is obtained by using appropriate materials and manufacturing methods for the ultra-high frequency (UHF) antenna by embroidering a multifilament stainless steel wire on textile support. The washing cycle tests have validated the applicability of this flexible and washable RFID tag, and its electromagnetic performance was experimentally assessed in an independent laboratory.

A Compact Coupled-Fed Loop Antenna for Mobile LTE Smartphones

A coupled-fed loop antenna with Octa-bands operation for long-term evolution (LTE) smartphones is proposed in this paper. The antenna occupies a nonground space of only 6.5 mm × 72 mm, and two wide-band operations can be achieved by exploiting the multimode characteristics of loop antenna and using high-pass matching circuits. In low band, the LTE700/GSM850/900 operation is achieved by the loop mode of 0.5 λ and matching chip capacitor which generates a dual-resonance mode at 0.74 GHz and 0.9 GHz. In high band, the 1 λ mode, the 1.5 λ mode, and the 2 λ mode of the entire loop are combined with the 0.5 λ mode of the left-side coupling loop to cover the DCS1800/PCS1900/UMTS 2100/LTE 2300/2500 operation bands. The measured average realized gains and efficiencies are approximately 1.56 dBi/2.38 dBi and 55.3%/63.6% in the two bands, and a good radiation pattern is achieved as well.