In-band full-duplex radios demand simultaneous transmit and receive (STAR) antennas with high isolation, compact and ultra-low profiles, and simple feed networks. Current state-of-the-art designs rarely meet all of these requirements at the same time. In this paper, we present a characteristic-mode-based design approach to achieve high isolation using compact fully-planar STAR antennas with a simple feed structure. The proposed method utilizes two characteristic modes of a conducting object as transmit and receive chains to achieve high isolation without a complicated self-interference cancellation circuit. The design example in this work is fully-planar, and it has a physical height of 1.6 mm. The measured -10 dB overlapped |S11|and|S22| fractional bandwidth of this STAR antenna is 2.5% and the measured isolation between the transmit and receive ports is greater than 30 dB over the entire frequency band of operation.

中文翻译：

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平面带内全双工天线的基于特征模式的设计

带内全双工无线电要求同时发射和接收（STAR）天线，并具有高隔离度，紧凑和超低外形以及简单的馈电网络。当前最先进的设计很少同时满足所有这些要求。在本文中，我们提出了一种基于特征模式的设计方法，以使用具有简单馈电结构的紧凑型全平面STAR天线实现高隔离度。所提出的方法利用导电物体的两个特征模式作为发射和接收链来实现高隔离度，而无需复杂的自干扰消除电路。这项工作中的设计示例是完全平面的，物理高度为1.6 mm。测得的-10 dB重叠| S11 |和| S22 | 该STAR天线的分数带宽为2。