S-parameters of Parylene C microwave microfluidic devices

Broadband S-parameter measurements of Parylene C microwave microfluidic devices from 100 MHz - 110 GHz. The Parylene C devices consisted of 400 nm platinum coplanar waveguides (CPW) (50 um center conductor, 5 um gaps, 200 um ground planes) deposited on fused silica with 6.5 um of Parylene C on top, capped with a PDMS microfluidic layer aligned over the CPWs. The dimensions of the PDMS microfluidic channels were approximately 210 um wide by 100 um deep. The total CPW line length was 10.000 mm and the channel length was 4.160 mm, where the channel was aligned over the center of the CPW. We measured the S-parameters of Parylene C devices filled with three different fluid conditions at different intervals over a 2 month period: H2O at 20 degrees Celsius, 1xPBS (phosphate-buffered saline) at 20 degrees Celsius, and 1xPBS at 37 degrees Celsius. We obtained measurements of both the fluid-filled and empty channel at each measurement day. We measured broadband S-parameters with a vector network analyzer and extender heads at a source power of -17 dBm on a temperature-controlled probe station. The S-parameters were calibrated to the probe tips with measurements of a gold reference chip in combination with multiline TRL in the NIST Microwave Uncertainty Framework. The differences in S-parameters from day 0 were plotted over time to observe changes in the dielectric properties of the Parylene C device during soaking.

宽带S参数测量了100 MHz至110 GHz频段的聚对二甲苯C微波微流控器件。这些聚对二甲苯C器件由400纳米铂共面波导（CPW）构成，其中中心导体直径为50微米，间隙为5微米，接地平面为200微米，沉积在熔融石英上，其上覆盖有6.5微米的聚对二甲苯C，并覆盖有PDMS微流控层，该层与CPW对齐。PDMS微流控通道的尺寸约为210微米宽，100微米深。总CPW线路长度为10.000毫米，通道长度为4.160毫米，通道位于CPW中心上方。我们在两个月的不同时间间隔内，对填充三种不同流体条件的聚对二甲苯C器件进行了S参数测量：20摄氏度的水，20摄氏度的1x磷酸盐缓冲盐水（PBS），以及37摄氏度的1xPBS。我们对每个测量日充满流体和空通道的S参数进行了测量。使用矢量网络分析仪和扩展头，在温度控制探针站上，以-17 dBm的源功率进行了宽带S参数测量。将S参数校准至探针尖端，通过测量金参考芯片以及结合NIST微波不确定性框架中的多线TRL进行校准。将0天与日间的S参数差异绘制成曲线，以观察聚对二甲苯C器件在浸泡过程中的介电特性变化。