Investigation for impact behavior of composite surface antenna
We study the impact characteristic and the performance of composite surface antenna (CSA). The antenna, which operates in GPS band (1.575 GHz) and DMB band (2.635 GHz), was embedded in composite sandwich structure consisting of glass/epoxy laminate, carbon/epoxy laminate, adhesive films and nomex honeycomb. When 20 J of impact energy was applied to arbitrary points on the antenna, the maximum contact force was 4 kN and the antenna proved resistant to impact. The gain of antennas after impact testing was about 6 dBi in GPS band and 4.5 dBi in DBS band.
Design of a dual‐mode annular ring antenna with a coupling feed
A dual‐mode annular ring antenna for both global positioning system (GPS) and satellite digital multimedia broadcasting (S‐DMB) is designed. The proposed antenna consists of a coupling feed line and four slots on an annular ring patch. A gap between the feed line and the annular ring patch is used for an input impedance matching; the slots are used for adjusting the resonant frequency of the TM21 mode at the DMB frequency. The antenna was fabricated and measured. The antenna resonates at the GPS and DMB frequencies with suitable bandwidths. It has a broadside radiation pattern in the GPS band and a conical beam radiation pattern in the DMB band. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 3011–3013, 2009; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.24796
Joint strength of aluminum ultrasonic soldered under liquidus temperature of Sn–Zn hypereutectic solder
Abstract In order to obtain high-strength aluminum joints, ultrasonic soldering of 1070 aluminum was conducted under liquidus temperature of Sn–Zn hypereutectic solder. A device for ultrasonic soldering was assembled, which propagated ultrasonic vibrations in a direction perpendicular to joining surfaces. This device joined 1070-Al using quasi-melting Sn–Zn hypereutectic solder without using any artificial spacers. The strength of the solder joints was evaluated by tensile tests. The optimum joining conditions were determined, and the effects of solder compositions and soldering temperature on the joint strength and the solder layer thickness were examined. In this ultrasonic soldering process, the highest tensile strength was obtained for the solder joints fabricated at 220 °C for the Sn–23Zn and Sn–40Zn solder compositions. The joint strength was equivalent to that of 1070-Al heat treated at 220 °C. The sound joints were obtained at 300 °C using Sn–82Zn solder, the liquid phase volume fraction of which was theoretically only 0.24. The present work also revealed that the thickness of retained solder layer in the joint after ultrasonic soldering could be estimated. Accordingly, ultrasonic soldering under the liquidus temperature of Sn–Zn hypereutectic solder could be a spacer-free soldering method to obtain high-strength aluminum joints.