Yesilyurt, UgurPolat, Hilal Koc2026-03-262026-03-2620231536-12251548-575710.1109/LAWP.2023.32345912-s2.0-85147215828https://doi.org/10.1109/LAWP.2023.3234591https://hdl.handle.net/20.500.14901/3245Yesilyurt, Ugur/0000-0003-0367-8805; Koc Polat, Hilal/0000-0003-2382-1736The vortex electromagnetic waves carrying the orbital angular momentum (OAM) are an increasing subject of study, and the design of a system capable of generating such waves is also of crucial importance. In this letter, a helical circular array (HCA) has been proposed to generate OAM radio beams. The proposed HCA has a more straightforward and more feasible scheme when compared to uniform circular arrays that require additional phase-shifting devices to form interelement phases. The heights of the proposed HCA elements along the $z$-axis are exploited to generate the different OAM modes. For the high-order OAM modes, the height of the HCA is made more compact with the help of the proposed helical circular subarray (HCSA) configurations with spiral phase positions providing a linear phase delay with the azimuth angle. In addition, at high mode values, the HCSA structure creates a smoother OAM vortex beam than HCA. The full-wave simulation results show that the proposed HCA scheme can be used to generate vortex electromagnetic waves with a spiral phase wavefront structure.eninfo:eu-repo/semantics/closedAccessPhased ArraysSpiralsAzimuthElectromagnetic ScatteringOptical VorticesMicrostrip Antenna ArraysMicrostripHelical Circular Microstrip Patch ArrayOrbital Angular Momentum (Oam)Vortex Electromagnetic WaveArticle