Performance enhancement of dual‐polarised dipole antenna using parasitic elements

Abstract

Abstract In this paper, a differentially fed broadband dual‐polarised dipole antenna with parasitic elements is proposed. The presented antenna comprises a pair of strip dipoles as driven elements, four square patches as internal parasitic elements, four rectangular patches with cut corners as external parasitic elements, and two pairs of coaxial cables as feeding structures placed orthogonally to excite the driven strip dipoles to achieve ±45° dual polarisation. Furthermore, two additional dual‐polarisation modes can be simulated and a broadband dual‐polarised antenna can be obtained by positioning the external and internal parasitic elements to the end and at the edge of driven elements, respectively. The presented antenna provides wide bandwidth using these dual‐polarisation modes. The measurement results indicate that the presented antenna has excellent characteristics with a wide impedance bandwidth (IBW) of 68.4% (|Sdd11| < −18 dB and 1.30–2.65 GHz) and high isolation (|Sdd21| < −30 dB) within the IBW. Additionally, the four‐element array of the broadband dual‐polarised antenna with differential feeding characteristics was designed. The results show that the measured IBW is 59.7% (|Sdd11| < −15dB and 1.35–2.50 GHz). By contrast, the isolation between the two ports exceeds 30 dB across the impedance passband and has potential applications in multiple wireless communication systems owing to the wide bandwidth coverage (frequency division duplexing (FDD), digital communication system (DCS), personal communication system (PCS), Universal Mobile Telecommunications System (UMTS), and Long Term Evolution (LTE) frequency bands).