Improving Isolation in Monostatic Simultaneous Transmit and Receive Systems Using a Quasi-Symmetrical Self-Interference Cancellation Architecture
Improving Isolation in Monostatic Simultaneous Transmit and Receive Systems Using a Quasi-Symmetrical Self-Interference Cancellation Architecture
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DOI：
10.1109/jmw.2022.3227242
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发表时间：
2023-04
影响因子：
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通讯作者：
M. N. Tarek;Marisol Roman Guerra;Anthony Nunez;Md Nazim Uddin;E. Alwan
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文献类型：
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作者：
M. N. Tarek;Marisol Roman Guerra;Anthony Nunez;Md Nazim Uddin;E. Alwan
对于同时发射（Tx）和接收（Rx），对于单基地全双工（FD）系统，通常的做法是使用单个天线和循环器来提供发射和接收无线电链之间的隔离。然而，目前市场上的大多数环行器被设计为提供12至20 dB的Tx/Rx端口隔离，这对于全双工（FD）微波通信是不够的。实际上，必须提供至少$> 30 dB的隔离，以防止由高功率发射信号泄漏引起的接收器灵敏度降低。为此，实际的同时发送和接收（星星）系统需要附加的消除级。在本文中，我们提出了一种新的星星系统，包括两个循环器，一个混合耦合器，和自干扰消除（SIC）电路，基于有限冲激响应（FIR）拓扑结构。我们的设计在仿真中实现了25 MHz带宽（即2.395-2.42 GHz）上的平均Tx/Rx端口隔离度为37 dB，最小和最大消除分别为35 dB和41 dB。一个原型制造和测试显示良好的协议与模拟。总而言之，原型实现了36 dB的平均消除，消除范围为33 dB至42 dB。
For simultaneous transmit (Tx) and receive (Rx), it is a common practice, with monostatic full duplex (FD) systems, to use a single antenna and a circulator to provide isolation between the transmit and receive radio chains. However, most circulators currently on the market are designed to provide 12 to 20 dB of Tx/Rx port isolation, which is not sufficient for full duplex (FD) microwave communication. In fact, it is necessary to provide at least $>$30 dB of isolation to prevent the receiver desensitization that is caused by the leakage of high-power transmit signals. For this reason, practical simultaneous transmit and receive (STAR) systems require additional cancellation stages. In this paper, we present a novel STAR system that incorporates two circulators, a hybrid coupler, and a self-interference cancellation (SIC) circuit, based on a Finite Impulse Response (FIR) topology. Our design achieves an average Tx/Rx port isolation of $\sim$37 dB over a 25 MHz bandwidth (viz. 2.395–2.42 GHz) in simulation, with a minimum and maximum cancellations of 35 dB and 41 dB, respectively. A prototype was fabricated and tested showing good agreement with the simulations. All in all, the prototype achieved an average cancellation of 36 dB, with a cancellation range of 33 dB to 42 dB.