一種表面電容元件之研究

Abstract

本論文中主要在探討一個表面電容感測器的特性，並且以模擬驗證表面電容值。並藉由感測器的介面電路偵測電容值的變化，以推導電容之幾何函數的變化。 一般電容性元件由兩層極板中間添加適當的介電質使用。而表面電容性元件可藉由PCB layout或MEMS製程刻劃出不同形狀，再經電容感測器的介面電路輸出電壓變化推導出電容對周圍環境的相對幾何函數變化。而電容感測器的介面電路，由一組時脈開關所組成，不同於一般偵測電容介面電路須將訊號調變發出，接收端解調分析才能使用，在節省電能消耗前提之下可進一步實現於晶片設計。 此電容感測器的介面電路分別PCB電路板製作與IC製程模擬驗證。選擇以TSMC 0.35μm 2P4M CMOS製程模擬感測器電路，量測電容範圍為8p~13pF，對應的頻率範圍0.5K~500KHz，電源供應為3.3V；驗證表面電容性元件採用Agilent ADS程式模擬，電容元件尺寸寬10mm長64.5mm。

The thesis is discussing the characteristic of the surface capacitive sensor and confirms the surface capacitance with simulation. The capacitance device in the past is composed of two parallel plates some dielectric in the between. But the surf capacitance device have different shape which made by PCB layout or MEMS process and it can judge the position that the capacitance to environment relative position by the variations in output voltage from the interface circuit of the capacitive sensor The interface circuit of the capacitive sensor is composed a clock switch and its different from the capacitance device which transmitted must modulation and received must demodulation. To realize IC design on the premise that reduces the electrical energy consumption. The interface circuit of the capacititive sensor uses electronic circuit board and was confirmed to IC simulation. It is fabricated in TSMC 0.35μm 2P4M CMOS technology process. The capacitor range is 8~13pf which correspond to frequency from 0.5k~500 kHz. The power supply is 3.3 V. The simulation tool is Agilent ADS program simulation. The capacitance device size is 10mm X 64.5mm.