Antenna integration with composite sandwich structures using gain enhancement methods

In this study, a new design method for antenna-integrated composite sandwich structures is proposed. First, the effects of sandwich geometry on antennas are investigated in the transmission line analogy. Changes in the gain of an antenna due to a sandwich geometry have been determined. For a facesheet layer, the condition that provides the greatest antenna gain is called the open condition and it is exploited to allow the presence of an antenna in the sandwich structure without loss of antenna performance. Two types of structures are designed, one which uses a stacked-patch microstrip antenna, and the other using an aperture-coupled microstrip antenna for wideband performance. The measured electrical performances of these fabricated structures show that the gains are superior to original antennas, and bandwidths are as wide as specified in the requirements of the present study. Structural performances are the same as those of a conventional sandwich structure, according to the three-point bending test, so that perfect integration is confirmed without reducing either of the mechanical and electrical performances.