A voltage-variable capacitor is an essential part of the matching element in radio frequency (RF) circuits, including the transmitting and receiving channel of mobile devices. However, the nonlinear characteristic of the voltage-variable capacitor produces unwanted harmonics when driven by a large exciting signal, which causes electromagnetic radiation spurious emission (RSE) complications. This article presents an efficient nonlinear capacitance polynomial model method coupling with harmonics test systems to predict the nonlinear behavior of the voltage-variable capacitor. In addition, a simple neural network model is trained to reduce the need to manually obtain the nonlinear parameters. Moreover, for devices exhibiting strong nonlinearity, an improved long short-term memory (LSTM) network is proposed to predict harmonics. Ultimately, the nonlinear parameter prediction for such devices is obtained quickly by implementing our developed method, which provides intuitive guidance in the design phase.

中文翻译：

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电压可变电容器的非线性行为建模方法

可变电压电容器是射频（RF）电路（包括移动设备的发送和接收通道）中匹配元件的重要组成部分。但是，当由大的激励信号驱动时，电压可变电容器的非线性特性会产生有害的谐波，这会导致电磁辐射杂散发射（RSE）复杂化。本文提出了一种有效的非线性电容多项式模型方法，并结合谐波测试系统来预测电压可变电容器的非线性行为。另外，训练了一个简单的神经网络模型，以减少手动获取非线性参数的需要。此外，对于表现出强非线性的设备，提出了一种改进的长短期记忆（LSTM）网络来预测谐波。最终，