A triband patch antenna with monopole-like and patch-like radiation patterns for multifunctional wireless systems is proposed. The antenna consists of a single square radiation patch with an annular slot, a ground plane, and a top-loaded metal sheet. The top-loaded metal sheet is shorted to the ground plane for producing a zeroth-order resonant (ZOR) mode, which has an omnidirectional radiation pattern at the lowest operation band, and its performance is robust to the location of the probe feed. With the annular slot and the off-center probe feed, a dual-resonant TM₀₁ mode is excited, yielding unidirectional radiation patterns for the two upper operation bands. The ZOR and the dual-resonant TM₀₁ modes can be independently controlled, and a triband antenna prototype with a square patch of 24 mm is fabricated and tested. The first bandwidth is 2.5–2.7 GHz with omnidirectional radiation pattern, the second and the third bandwidths with unidirectional radiation are 3.3–3.9 GHz and 4.8–6.1 GHz, and the realized gains over the three bands are about 2.6, 6.5, and 7.5 dBi, respectively.

中文翻译：

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用于多功能无线系统的具有类单极和类贴片辐射方向图的三频贴片天线

提出了一种用于多功能无线系统的具有单极样和类样辐射图的三频贴片天线。该天线由一个带有环形槽的单个方形辐射贴片，一个接地平面和一个顶部加载的金属板组成。顶部负载的金属片短接至接地层，以产生零阶谐振（ZOR）模式，该模式在最低工作频段具有全向辐射方向图，并且其性能对探针馈送的位置很稳定。通过环形槽和偏心探头进给，可以激发双共振TM ₀₁模式，从而为两个较高的操作频段产生单向辐射方向图。ZOR和双共振TM ₀₁两种模式可以独立控制，并制造并测试了具有24 mm方形贴片的三频天线原型。具有全向辐射模式的第一带宽为2.5–2.7 GHz，具有单向辐射的第二和第三带宽为3.3–3.9 GHz和4.8–6.1 GHz，并且在三个频带上的已实现增益分别约为2.6、6.5和7.5 dBi ， 分别。