基于液体金属的接触PIM抑制方法和实验验证

Liquid metal based contact PIM suppression schemes and experimental study

接触非线性是射频设备和电路中产生无源互调(passive intermodulation,PIM)信号的重要原因之一。基于对接触结点射频等效电路的分析,提出了一种基于共晶镓铟合金(eutectic gallium-indium,EGaIn)的PIM抑制方法。EGaIn不同于传统的焊锡,它可以在室温下实现接触结位置上的稳定、可重构连接。首先分析了射频(radio frequency,RF)下的金属接触结的电路模型。其次设计并实现了两个包含不同金属接触结构且工作在2.6GHz的平面倒F天线(planar inverted F antenna,PIFA)。最后比较了EGaIn焊接前后PIFA的互调水平,其中对PIM指标的最大抑制程度为35dB。验证了EGaIn可以在室温下对PIFA的接触结点进行可重构焊接,这为电连接中的非线性抑制提供了一种参考方法。

Contact nonlinearity is one of the important causes of passive intermodulation(PIM)signals in radio frequency equipment and circuits.Based on the analysis of the radio frequency equivalent circuit of the contact node,this paper proposes a PIM suppression method using eutectic gallium-indium(EGaIn)liquid metal alloy.EGaIn is different from traditional solder because it can achieve stable and reconfigurable connections at room temperature for the contact node positions.Firstly,the circuit model of the contact node under radio frequency is analyzed.Then,two printed inverted-F antennas(PIFAs)with different metal contact structures operating at 2.6GHz are designed and implemented.Finally,the intermodulation indices of the PIFA before and after EGaIn soldering are compared,with the PIM index being reduced by up to 35dB.This paper verifies that EGaIn can achieve reconfigurable soldering of the contact node positions of the PIFA at room temperature,providing a reference method for nonlinear suppression in electrical connections.