Fractal Circularly Polarized Leaky-Wave Antenna for X-Band CubeSat Communication

This study presents the design and optimization of a circularly polarized fractal leaky-wave antenna (LWA) designed for X-band CubeSat communication systems. The proposed antenna is based on a via-less substrate-integrated waveguide (SIW) structure. It utilizes composite right-/left-handed (CRLH) transmission-line principles to achieve a high-impedance boundary and enhanced radiation performance. The work focuses on optimizing the antenna structure for operation at 8 GHz by investigating the effects of key design parameters, including the slot width (Ws), bent length (Ls1), inter-slot spacing (dslot), and number of periodic unit cells (n). Antenna performance is evaluated in terms of the reflection coefficient (S11), the axial ratio (AR) for circular polarization, and the gain. Comprehensive simulations are performed using CST Studio Suite to analyze the antenna's electromagnetic behavior. The optimized design, with Ws = 0.5 mm, Ls1 = 1.8 mm, dslot = 1.8 mm, and n = 20, achieves AR < 3 dB and high gain across the target band, demonstrating its suitability for cubesat applications requiring beam steering and circular polarization.