ABSTRACT In this article, asymmetrical mirror-imaged monopole antenna comprises a rectangular patch with tuneable stub and supported with modified ground structure (MGS) is investigated. The proposed antenna is characterised for dual band dual polarised (DBDP) radiations and can operate at 2.45 GHz for Wi-Fi and WLAN systems (2.4–2.485 GHz) and 5.45 GHz for WLAN band (WLAN band: 5.2–5.8 GHz) with the corresponding polarisations. A rectangular patch integrated with tuneable stub and a pair of asymmetrical inverted L-shaped slots positioned at ground plane is responsible for circularly polarised higher band; while a parasitic patch is created due to slotting of a mirror-imaged stub from the extended ground plane which is accountable for lower frequency band. The fabricated prototype shows that the measured Impedance bandwidths (VSWR < 2) are 350 and 1770 MHz for lower and higher frequency bands, respectively. The measured axial ratio bandwidth (AR < 3 dB) is yielded as 1450 MHz centred at 5.44 GHz for higher frequency band. The peak gains are measured as 4.3 and 4.15 dB for lower and higher frequency band, respectively. For the prototype antenna, substantial 3-dB beamwidth is found along with good cross polarisation suppression.

中文翻译：

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具有改进的 DBDP 辐射接地结构的非对称镜像单极天线

摘要 在本文中，非对称镜像单极天线包括一个带有可调谐短截线的矩形贴片，并由改进的接地结构 (MGS) 支撑。所提议的天线具有双频段双极化 (DBDP) 辐射特性，可以在 2.45 GHz 的 Wi-Fi 和 WLAN 系统（2.4-2.485 GHz）和 5.45 GHz 的 WLAN 频段（WLAN 频段：5.2-5.8 GHz）下运行相应的极化。一个集成了可调短截线的矩形贴片和一对位于地平面的不对称倒 L 形槽负责圆极化的高频段；而寄生贴片是由于从扩展的接地平面开槽镜像短截线而产生的，这负责较低的频带。制造的原型显示测量的阻抗带宽 (VSWR < 2) 对于较低和较高频段，分别为 350 和 1770 MHz。测得的轴比带宽 (AR < 3 dB) 为 1450 MHz，以 5.44 GHz 为中心，用于更高频段。对于较低和较高频段，峰值增益分别测量为 4.3 和 4.15 dB。对于原型天线，发现了相当大的 3-dB 波束宽度以及良好的交叉极化抑制。