فهرست نشریات علمی دسترسی آزاد ایران

This paper presents a novel, fully planar circularly polarized periodic leaky-wave antenna (CP-PLWA) designed for wide-beam scanning in the 70 GHz band for millimeter-wave radar applications. A complementary split ring resonator half-mode substrate integrated waveguide (CSRR-HMSIW) feed structure is employed, offering a low-loss, and readily manufacturable implementation. The key innovation is the integration of cascaded X-shaped slots within the radiating patch, which facilitates controlled surface current perturbation and optimized excitation of orthogonal E-field components, resulting in a significantly enhanced circular polarization bandwidth. This design enables backward-to-forward beam scanning while maintaining a fully planar, via-free architecture. Simulated results demonstrate a 20.1% impedance bandwidth (64.4–77.75 GHz), an axial ratio bandwidth exceeding 13.6% (66–75 GHz, AR < 3 dB), and a wide scan angle from –15° to +60°. A gain exceeding 13 dBi (peaking at 16 dBi) is achieved with a simulated radiation efficiency greater than 97%. This compact, fully planar design, fabricated on a Rogers RT/duroid 5880 substrate, advances the state-of-the-art in CP LWAs for 70 GHz millimeter-wave radar systems by simultaneously addressing critical limitations of prior art: achieving wide CP bandwidth in a planar configuration, eliminating fabrication-via complexity, and maintaining high efficiency across a wide scanning range. The proposed antenna offers a promising solution for future high-performance radar applications requiring compact, wideband, and frequency-scanned circularly polarized radiation.