A smart layer module design utilizing a flexible printed circuit process is developed in this paper. The smart layer module, composed of two single-sided flexible polyimide films, piezoelectric sensor/actuator(s) and a pin connector, provides the advantages of convenience, efficiency, and performance when embedded in a smart structure. The problems of the piezoelectric sensor/actuator lead-wires often being easily damaged during fabrication and the short-circuiting of the sensor/actuator by carbon/graphite fibers can be solved. Tensile and modal tests show that the embedded smart layer module increases both the stiffness and strength of a composite laminated smart structure. Experiments of vibration measurement and suppression validate that the smart layer module is effective in engineering applications.

With the increasing wind penetration into the power system, guidelines of the operating reserve need to be revised to ensure system security. Due to the uncertain characteristics of the wind production, the general way of the reserve management for wind integration is to provide additional reserve margin by conventional plants. Such a strategy could not only increase the operating cost but also impose additional unit stress during the frequency event. This paper presents a strategy that incorporates doubly-fed induction generator (DFIG) wind farms to actively provide primary reserve for frequency control. The wind reserve allocation according to available wind speed is proposed. An integrated system that consists of the traditional units and DFIG wind farms has been developed to assess the frequency response and generating interactions. Simulation results are discussed to illustrate the superiority of the presented strategy in reserve operation.Index Terms-Doubly-fed induction generator (DFIG), operating reserve, wind power.

In this communication, microstrip antenna on fiber reinforced anisotropic substrates has been considered in aerospace applications; however, the antenna's optical axis may not necessarily be colinear with any of the substrate's principal axes and that leads to a nondiagonal permittivity matrix (tensor). This work extends the studies of microstrip antenna on isotropic substrate and on uniaxial substrate to analyze antenna performance on fiber reinforced anisotropic substrates, where the permittivity matrix has five dielectric constants because of the substrate's fiber direction. The solution is based on modal analysis so that the wave immittance can be derived in a closed form. Analyses and experimental verification show that the antenna performance is strongly influenced not only by the permittivity along the principal axes but also by the fiber direction of the substrate.Index Terms-Anisotropic substrate, microstrip antenna, spectral domain analysis.

No abstract

Fiber-reinforced composite structures can be tailored to desire mechanical properties and to embed microstrip antenna in aerospace applications. The electromagnetic characteristics of a microstrip antenna on isotropic and uniaxial substrates have been known, but that embedded in composite laminated substrates remain unavailable to date. This work aims at analyzing the performance of microstrip antenna embedded in composite laminated substrates by spectral domain analysis. Parameter studies are conducted to investigate the effects of the substrate's dielectric constants, the fiber directions (the orientation between the antenna and the laminate layers), and the stacking sequence on antenna's resonant frequency and radiation pattern. The antenna size when embedded in composite laminated substrates is larger than that when attached on isotropic substrates, or conversely, the resonant frequency will deviate lower if assuming the substrate as isotropic. The far-field pattern in composite laminated substrates is more 'directional' than that in isotropic substrates. The antenna gain in the substrates of symmetric stacking with ±45°fiber direction is 20 dB better than that in isotropic substrates in some elevations.