Modern antenna arrays desire antenna apertures which can support a wide frequency range and reconfigurable polarization states. It is challenging to realize such antenna apertures with high isolation among different antenna elements when they are closely packed, particularly for wide-band (>2:1 frequency ratio) operations. In this paper, we demonstrated switchable-band antenna arrays which can be reconfigured from S to C band with an instantaneous bandwidth close to 2:1. The major novelty in this antenna array is that a new arraying technique is adopted to reduce the number of feeding ports by 50%. As a result, the isolation among antenna elements can be significantly improved, thereby increasing the overall radiation efficiency. It should be noted that vertical, horizontal and circular polarizations are supported by this antenna array when all ports are provided with appropriate phases. Herein two arrays are demonstrated. Array I is based on a fractal-shaped slot-ring structure. Each antenna element is fed by a microstrip along the diagonal direction. The common antenna aperture can be reconfigured to operate at 2.5-4.0 GHz or 4.2-7.2 GH, using PIN diode switches. Array II is extended from Array I but with an Artificial Magnetic Conductor (AMC) ground to enhance the instantaneous bandwidth to 2:1. The length of the microstrip feeding lines are reduced to enable modular design. In addition, PIN diode switches are embedded in the feeding lines to further improve the isolation and radiation efficiency. The return losses, port isolations, radiation patterns, gains, radiation efficiencies and IIP3 are simulated and measured.

中文翻译：

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一种新的宽带可切换和偏振可重构天线阵列阵列技术


现代天线阵列需要能够支持较宽频率范围和可重构极化状态的天线孔径。当不同天线元件紧密排列时，实现这种在不同天线元件之间具有高隔离度的天线孔径具有挑战性，特别是对于宽带（>2:1频率比）操作。在本文中，我们演示了可切换频段天线阵列，它可以从 S 频段重新配置到 C 频段，瞬时带宽接近 2:1。该天线阵列的主要创新之处在于采用了新的阵列技术，使馈电端口数量减少了50%。结果，可以显着改善天线元件之间的隔离度，从而提高整体辐射效率。应当注意的是，当所有端口都提供适当的相位时，该天线阵列支持垂直、水平和圆极化。这里演示了两个阵列。阵列 I 基于分形槽环结构。每个天线元件由沿对角线方向的微带馈电。使用 PIN 二极管开关，可以将公共天线孔径重新配置为在 2.5-4.0 GHz 或 4.2-7.2 GH 下运行。阵列 II 是阵列 I 的扩展，但具有人工磁导体 (AMC) 接地，以将瞬时带宽增强至 2:1。微带馈线的长度被缩短以实现模块化设计。此外，馈线中还嵌入了PIN二极管开关，进一步提高了隔离度和辐射效率。模拟并测量回波损耗、端口隔离、辐射方向图、增益、辐射效率和 IIP3。