A Polarization Reconfigurable 3D Printed Dual Integrated Quadrifilar Helix Antenna Array Embedded Within a Cylindrical Dielectric Mesh

This article presents a polarization reconfigurable dual integrated quadrifilar helix antenna array that is embedded within a cylindrical-shaped mesh of dielectric material. The entire structure is 3-D-printed and equipped with grooves to support the eight radiating elements and accordingly enforce the helical pitch and orientation. The dual antenna array, acting as one, features double fractional bandwidth (i.e., 30%) while exhibiting polarization reconfigurability by switching between left-handed and right-handed circular polarization states. More specifically, the proposed structure operates over the span of frequencies between 1.7 and 2.3 GHz while ensuring a circularly polarized behavior. The polarization reconfigurability is obtained by changing the phase excitation of the eight helical arms. Accordingly, a dedicated feeding network is proposed to achieve the required phase reconfiguration. A prototype is fabricated and tested as a proof of concept, where the measured results agree well with the simulated data. The 3-D-printed fabricated prototype reconfigures its circularly polarized behavior over the entire operating bandwidth with a maximum measured realized gain of 6.4 dBic, an axial ratio that varies between 0.5 and 2.5 dB, and cross-polarization levels of at least 20 dB along the direction of maximum radiation.