In this article, an elegant approach is presented for designing multi-band multi-mode rectangular microstrip antennas (MSAs) with high isolation between the bands. The coupling properties of a gap (an extended slot), which is introduced in a rectangular MSA operating in the $TM_{010}$ and $TM_{100}$ modes, are first qualitatively explained through field equivalence theory and image theory. It is shown that even though the slot appears “transparent” (i.e., strongly couples the two sections of the MSA) to the $TM_{010}$ mode, it effectively decouples the two sections of the MSA in the $TM_{100}$ mode. As a proof-of-concept, the design technique is applied to a conventional patch to achieve dual-band operation with $39~dB$ of measured isolation between the bands. The design concept is then extended to achieve a quad-band antenna design with $30~dB$ of measured isolation between all of its bands. Compared to other methods the proposed one preserves the low-profile of microstrip antennas and provides a simple way to design and fabricate multi-band and multi-mode antennas. Therefore, this method is very well suited for designing antennas for next generation communication systems.

中文翻译：

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多频带微带贴片天线的去耦模式

在本文中，提出了一种优雅的方法，用于设计在频带之间具有高度隔离的多频带多模矩形微带天线（MSA）。间隙（扩展的槽）的耦合特性，是在矩形MSA中引入的。 $ TM_ {010} $ 和 $ TM_ {100} $ 首先通过场等效理论和图像理论定性地解释了这些模式。结果表明，即使该插槽看起来“透明”（即，将MSA的两个部分牢固地耦合在一起）也与 $ TM_ {010} $ 模式，可以有效地将MSA的两个部分解耦 $ TM_ {100} $ 模式。作为概念验证，将设计技术应用于常规贴片，以实现双频工作 39〜dB美元 频带之间测得的隔离度。然后扩展设计概念，以实现具有以下特征的四频天线设计： $ 30〜dB $ 所有频段之间的隔离度。与其他方法相比，提出的方法保留了微带天线的低轮廓，并提供了一种设计和制造多频带和多模式天线的简单方法。因此，该方法非常适合用于下一代通信系统的天线设计。