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
Compressive Strength of Composite Sandwich Panels After Impact Damage: An Experimental and Analytical Study
The effect of low speed impact on the compressive strength of graphite/epoxy sandwich panels was examined experimentally and analytically. Various impactor sizes and impact energy levels were used. Impact damage was found to decrease the compressive strength of panels in this investigation by up to 33%. The use of film adhesive as an interply layer was found to reduce the extent of damage and increase the residual compressive strength. A one-parameter model to predict compressive failure of impact damaged panels is presented. The theoretical predictions are in good agreement with experimental results. Some of the factors affecting the panel behavior are also discussed.