In the current state of the art, WiFi-alike standards require achieving a high Image Rejection Ratio (IRR) while having low power consumption. Thus, quadrature structures based on passive ring mixers offer an attractive and widely used solution, as they can achieve a high IRR while being a passive block. However, it is not easy for the designer to know when a simple quadrature scheme is enough and when they should aim for a double quadrature structure approach, as the latter can improve the performance at the cost of requiring more area and complexity. This study focuses on the IRR, which crucially depends on the symmetry between the I and Q branches. Non-idealities (component mismatches, parasitics, etc.) will degrade the ideal balance by affecting the mixer and/or following/previous stages. This paper analyses the effect of imbalances, providing the constraints for obtaining a 40 dB IRR in the case of a conversion from a one-hundred-megahertz signal to the five-gigahertz range (upconversion) and vice versa (downconversion) for simple and double quadrature schemes. All simulations were carried out with complete device models from 65 nm standard CMOS technology and also a post-layout Monte Carlo analysis was included for mismatch analysis. The final section includes guidelines to help designers choose the most adequate scheme for each case.

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CMOS无源混频器的非理想性分析

在当前的现有技术中，类似WiFi的标准要求在具有低功耗的同时实现高图像抑制比（IRR）。因此，基于无源环形混频器的正交结构提供了一种有吸引力且广泛使用的解决方案，因为它们可以在成为无源模块的同时实现较高的IRR。但是，对于设计人员而言，要知道一个简单的正交方案何时就足够以及何时应该采用双正交结构方法并不容易，因为后者可以以需要更多面积和复杂性为代价来提高性能。这项研究的重点是IRR，它主要取决于I和Q分支之间的对称性。非理想情况（组件失配，寄生效应等）将通过影响混频器和/或后续/先前的阶段而降低理想的平衡。本文分析了不平衡的影响，对于简单和双正交方案，从100兆赫兹信号转换到5吉赫兹范围（上变频），反之亦然（下变频），则提供了获得40 dB IRR的限制。所有仿真均使用65纳米标准CMOS技术的完整器件模型进行，并且还包括布局后的蒙特卡洛分析，用于失配分析。最后一部分包括指导原则，以帮助设计人员为每种情况选择最合适的方案。所有仿真均使用65纳米标准CMOS技术的完整器件模型进行，并且还包括布局后的蒙特卡洛分析，用于失配分析。最后一部分包括指导原则，以帮助设计人员为每种情况选择最合适的方案。所有仿真均使用65 nm标准CMOS技术的完整器件模型进行，并且还包括布局后的蒙特卡洛分析，用于失配分析。最后一部分包括一些指南，可帮助设计人员为每种情况选择最合适的方案。