Flexible patch antenna array operating at microwaves based on thin composite material

Abstract

This paper presents an innovative route to fabricate conformal patch antenna arrays based on a flexible mesh-style conductive fabric/E-glass fiber composite laminate with improved performance at microwaves. On the one hand, the ohmic loss in the antenna array is restricted by integrating a highly conductive fabric into an E-glass fiber composite laminate and by using it as feeding lines and radiating elements after its precise machining by laser technology. On the other hand, the dielectric loss is restricted by inserting a foam layer (with dielectric characteristics close to those of the air) between the laminate substrate and the ground plane which is made of the highly conductive mesh-style fabric. The bending effect of the antenna array on its radiation pattern is minimized by applying a phase offset through phase shifters at the feeding lines of the most curved patches. The high radiation performance in gain and efficiency at 5.8 GHz (11.9 dBi and 75% in a flat configuration, and 8.7 dBi and 75% in a 50 mm-radius bending configuration, respectively), the seamless integration process, and the flexible mechanical properties of such composite antenna arrays pave the way for their promising and efficient integration into various devices, objects, and vehicles made of composite laminate materials.