کنفرانس مهندسی برق ایران

صفحه اصلی / سی و چهارمین کنفرانس بین المللی مهندسی برق

An LTCP Converting Unit Cell with Inhomogeneous Dielectric for Possible Integration Into Reflectarray Antenna

نویسندگان :

Soroosh Ghaffari¹ Mahmood Rafaeibooket²

1- دانشگاه زنجان 2- دانشگاه زنجان

کلمات کلیدی :

Reflectarray antenna،Circular polarization،Linear-To-Circular Polarization converter،Low-cost unit cell

چکیده :

Abstract—This paper presents a low-cost microstrip reflectarray unit cell designed for circular polarization (CP) operation at a center frequency of 11.2 GHz. The proposed element employs an FR4 substrate together with a self-enclosed configuration, removing the need for an external radome and simplifying fabrication. The unit cell also functions as a linear-to-circular polarization converter, transforming an incident linearly polarized wave into a circularly polarized reflected wave. The geometry comprises a perforated circular patch, an orbicular ring, a pair of variable-length arc stubs acting as phase-delay lines, and a pair of fixed stubs. To reduce the dielectric losses inherent to FR4, air holes are incorporated into the substrate. Optimizing these parameters yields a wide reflection-phase range and an improved axial ratio. Full-wave simulations based on the Finite Element Method (FEM) demonstrate a phase range exceeding 290° over 10.8–11.6 GHz while maintaining an axial ratio below 3 dB, confirming robust CP performance. A two-cell prototype is fabricated and experimentally characterized using a waveguide simulator, with measured results showing good agreement with simulations.