This letter presents a novel patch antenna with a reconfigurable bidirectional pattern. By simply placing seven shoring pins underneath a circular patch, the proposed antenna enables the switch-overs between two orthogonal bidirectional beams and a quad-beam via controlling four p-i-n diodes. Characteristic mode analysis is applied here to provide physical insights on its working mechanism and also offer proper feeding ways for independent excitation of the desired modes. The proposed antenna was fabricated and measured. Vertically polarized bidirectional beams switchable in two orthogonal directions are generated at 3.4 GHz with peak gains of 6.8 and 7.3 dBi. As all p-i-n diodes are on, their synthetic pattern in a quad-beam can be obtained as well.

中文翻译：

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使用特征模式分析的模式可重构双向天线设计

这封信展示了一种具有可重构双向模式的新型贴片天线。通过简单地在圆形贴片下方放置七个支撑销，所提出的天线可以通过控制四个 pin 二极管实现两个正交双向波束和一个四波束之间的切换。此处应用特征模式分析以提供对其工作机制的物理见解，并为所需模式的独立激发提供适当的馈送方式。所提出的天线是制造和测量的。可在两个正交方向切换的垂直极化双向波束在 3.4 GHz 频率下产生，峰值增益为 6.8 和 7.3 dBi。由于所有 pin 二极管都打开，因此也可以获得四光束中的合成图案。