C-Band flexible and portable circularly polarized textile-reflectarray (TRA)

Abstract

A novel C-Band flexible, and portable circularly polarized (CP) textile-reflectarray (TRA) design using conductive thread, is presented. Among several textile samples under test (SUT), three of them are selected based on their suitable material characteristics. The material parameters of SUT are extracted using resonance technique which is further are in the design of the TRA elements. A conductive cross-bowtie shape is used as a TRA element. To achieve flexibility, and the roll-ability in the proposed TRA, the solid ground (GND) is replaced with a frequency selective surface (FSS). A slotted circular patch is used as an element for the FSS. The upper radiating layer and the lower FSS layer are to be embroidered using conductive thread. The phase characteristics of the proposed TRA element are obtained using the rotation technique where the cross-bowtie elements rotate counter clockwise (CCW) for the spatial delay phase compensation. An FSS-based 15 × 15 TRA is designed in the C-Band using the CST microwave studio for the full wave analysis. A left hand circular polarized (LHCP) helical feed is used to excite TRA. The TRA performance is evaluated at 5.8 GHz. The proposed TRA provides, a maximum gain of 24.2 dB, a 1.5 dB axial ratio (AR) bandwidth of 12.8 %, and highest aperture efficiency of 30.3 %.