This article presents the design of an offset CPW‐fed slot antenna which exhibits a narrow impedance bandwidth (IBW; |S₁₁| ≤ −10 dB) extending from 1.20 GHz to 1.45 GHz and another wide impedance bandwidth from 1.86 GHz to 8.4 GHz thus covering almost all the conventional operating frequencies. The antenna is loaded with semicircular and rectangular stubs and meandered microstrip lines to realize circular polarization at 1.35 GHz, 3.3 GHz, 4.9 GHz, and 7.5 GHz with axial ratio bandwidth (axial ratio ≤ 3 dB) of 19.25% (1.2‐1.46 GHz), 4.24% (3.24‐3.38 GHz), 4.1%(4.8‐5 GHz), and 5.2% (7.3‐7.69 GHz) respectively thus covering the GPS, WiMAX, WLAN, and X‐band downlink satellite communication application bands. The mechanism of generation of CP is discussed using vector analysis of surface current density distribution. The gain is fairly constant in the wide IBW region with maximum fluctuation of 1.2 dB. The structure is compact with an overall layout area of 0.27λ × 0.27λ, where λ is the free‐space wavelength corresponding to the lowest circular polarized (CP) frequency. A comparison of the proposed antenna with previously reported structures is performed with respect to impedance bandwidth, compactness, number of CP bands, LHCP to RHCP isolation and gain to comprehend the novelty of the proposed design. A prototype of the proposed antenna is fabricated and the measured results are in accord with the simulated results.

中文翻译：

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一种宽带紧凑型天线，在其工作区域内具有四圆极化带

本文介绍了一种偏置CPW馈送的缝隙天线的设计，该天线具有窄的阻抗带宽（IBW; | S ₁₁| ≤-10 dB）从1.20 GHz扩展到1.45 GHz，另一宽阻抗带宽从1.86 GHz扩展到8.4 GHz，从而几乎覆盖了所有常规工作频率。天线上装有半圆形和矩形短截线以及弯曲的微带线，可实现1.35 GHz，3.3 GHz，4.9 GHz和7.5 GHz的圆极化，轴向比率带宽（轴向比率≤3 dB）为19.25％（1.2-1.46 GHz） ，4.24％（3.24-3.38 GHz），4.1％（4.8-5 GHz）和5.2％（7.3-7.69 GHz），从而覆盖了GPS，WiMAX，WLAN和X波段下行链路卫星通信应用频段。使用表面电流密度分布的矢量分析讨论了CP的生成机理。在宽的IBW区域中，增益相当恒定，最大波动为1.2 dB。结构紧凑，总布局面积为0.27λ×0。27λ，其中λ是对应于最低圆极化（CP）频率的自由空间波长。在阻抗带宽，紧凑性，CP频段数量，LHCP与RHCP隔离和增益方面进行了建议天线与先前报告结构的比较，以了解建议设计的新颖性。制造了所提出的天线的原型，并且测量结果与仿真结果一致。