A microstrip feed line‐based continuous frequency‐tunable dual‐band multiple‐input multiple‐output (MIMO) antenna is proposed in this article. The proposed antenna comprises four hook‐shaped radiators placed orthogonally to one another. The overall dimensions of the antenna are 45 × 45 × 1.6 mm³ (0.77λ_g × 0.77λ_g × 0.027λ_g [where λ_g is the guided wavelength at the lower tunable resonant frequency]). The proposed antenna operates at dual‐band, while tunability in the resonant frequencies is achieved by connecting varactor diodes with the radiating patches. The lower resonant band of the antenna can be tuned from 2.45 to 2.83 GHz (with the isolation of more than 17 dB in the whole operating band) and the upper frequency band is tunable from 5.14 to 6.3 GHz (with the isolation of more than 22 dB in the whole operating band). The properties of the antenna such as reflection coefficients, mutual couplings, radiation patterns, channel capacity losses, and multiplexing efficiencies are verified by measuring the fabricated prototype. The envelope correlation coefficient of the antenna is <0.11 for the lower frequency band and is <0.16 for the higher frequency band for all tuning cases. The proposed antenna is suitable for use in compact multiband MIMO applications because of its small size, dual‐band characteristics, continuous frequency tuning capability, and good MIMO parameters.

中文翻译：

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基于变容二极管的双频可调多输入多输出天线

本文提出了一种基于微带馈线的连续频率可调双频多输入多输出（MIMO）天线。拟议的天线包括四个相互正交放置的钩形辐射器。天线的整体尺寸为45×45×1.6毫米³（0.77 λ_克×0.77 λ_克×0.027 λ_克[其中λ_克是在较低的可调谐振频率处的引导波长]）。拟议中的天线在双频下工作，而谐振频率的可调谐性是通过将变容二极管与辐射贴片相连来实现的。天线的较低谐振频带可以在2.45至2.83 GHz范围内调谐（在整个工作频带内隔离度超过17 dB），而较高频带可以在5.14至6.3 GHz之间进行调谐（隔离度超过22以上）。整个工作频带中的dB）。天线的特性，例如反射系数，相互耦合，辐射方向图，信道容量损耗和多路复用效率，可通过测量制造的原型来验证。对于较低频段，天线的包络相关系数< 0.11，并且<所有调谐情况下的较高频段为0.16。所建议的天线尺寸小，具有双频特性，连续的频率调谐能力和良好的MIMO参数，因此适合用于紧凑型多频带MIMO应用。