Compact circularly polarized dual band antenna with modified patch for ISM and V2X communication systems

This paper introduces a novel design and development of a compact circularly polarized antenna operating at two distinct frequency bands, 2.5 GHz and 6 GHz. The innovation lies in using a modified circular patch and a uniquely designed feeding element, which optimize circular polarization performance while maintaining a low-profile form factor. Fabricated on an FR4 substrate with an overall thickness of 1.6 mm and dimensions of 62 mm × 62 mm × 1.6 mm, corresponding to approximately 0.5167λ × 0.5167λ × 0.0133λ at 2.5 GHz, the antenna achieves a compact configuration well-suited for space-constrained applications. Extensive simulations and measurements show close agreement, with axial ratios below 3 dB across both operational bands, ensuring effective circular polarization. The antenna achieves peak gains of 1.8 dBi at 2.5 GHz and 3.8 dBi at 6 GHz, highlighting its ability to combine compactness, dual-band functionality, and strong radiation characteristics. This proposed design provides a groundbreaking solution for Industrial, Scientific, and Medical (ISM) and Vehicle-to-Everything (V2X) communication systems, addressing the increasing demand for efficient, dual-band, and space-saving wireless communication solutions.