This paper proposes a device level solution to achieve linear frequency tuning with respect to a tuning voltage (V tune ) sweep in an inductor (L)–capacitor (C) resonant system. Since the linearity of the resonant frequency vs. tuning voltage (f–V) relationship in an LC-resonant system is closely related to the C–V response characteristic of the varactor, we propose a C–V response tunable varactor to realize the linear frequency tuning. The proposed varactor was fabricated using microelectromechanical system (MEMS) surface micromachining. The fabricated MEMS varactor has the ability to dynamically change the C–V response characteristic according to a curve control voltage (V curve-control ). When V curve-control was increased from zero to 9 V, the C–V response curve was changed from a linear to a concave form (i.e., the capacitance decreased quickly in the low tuning voltage region and slowly in the high tuning voltage region). This change in the C–V response characteristic resulted in a change in the f–V relationship, and we successfully demonstrated almost perfectly linear frequency tuning in the LC-resonant system, with a linearity factor of 99.95%.

中文翻译：

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使用C–V响应可控MEMS变容二极管的LC谐振系统中的线性频率调谐

本文提出了一种器件级解决方案，以实现针对电感器（L）-电容器（C）谐振系统中的调谐电压（V tune）扫描的线性频率调谐。由于LC谐振系统中谐振频率与调谐电压（f–V）的线性关系与变容二极管的C–V响应特性密切相关，因此我们提出了C–V响应可调变容二极管以实现线性频率调谐。拟议的变容二极管是使用微机电系统（MEMS）表面微加工制造的。制成的MEMS变容二极管具有根据曲线控制电压（V curve-control）动态改变C–V响应特性的能力。当V曲线控制从零增加到9 V时，C–V响应曲线从线性变为凹形（即，电容在低调谐电压区域快速下降，在高调谐电压区域缓慢下降） 。C–V响应特性的这种变化导致f–V关系的变化，并且我们成功地展示了LC谐振系统中几乎完美的线性频率调谐，其线性因子为99.95％。