摘要 隨著微波技術的日趨重要，高電子移導率電晶體（HEMT）在高頻電路所扮演的角色也越來越重要；本論文是以單閘極以及雙閘極高電子移導率電晶體特性探討為主，並將雙閘極高電子移導率電晶體應用在2.4GHz微波放大器上。 本論文第二章首先討論單閘極空乏型元件與單閘極增強型元件的直流與高頻特性，並利用Yang-Long 直流量測及Cold-FET高頻量測方法，萃取電晶體外部寄生參數，再經由矩陣轉換求得內部本質元件參數值，進而建立小訊號模型，並利用cascode的方式，預測雙閘極元件的fT以及fmax。 第三章我們討論雙閘極增強-增強型元件的直流與高頻特性，並分析為什麼雙閘極增強-增強型元件的功率表現不如單閘極增強型元件；第四章則是討論雙閘極增強-空乏型元件的直流、高頻與功率特性，並將這兩種雙閘極元件做綜合比較；在第五章則是利用這兩種雙閘極元件的特性，設計2.4GHz微波放大器；第六章歸納整篇論文結果，並做一結論。 ABSTRACT The microwave technology is important day by day, and HEMT is important in High frequency circuits. This thesis contents are conferred on single gate and dual gate pHEMT device performance, we also using the dual gate pHEMT in a 2.4GHz microwave amplifier design. In chapter two, we discussed the single gate pHEMT DC and RF performance. We used Yang-Long DC measurement and Cold-FET RF measurement to extract external parasitic parameter, and we also extracted intrinsic element parameter by matrix transform to establish small signal model. By the way, we used cascode topology to forecast the maximal power gain cut off frequency (fmax) of dual gate pHEMT. In chapter three, we discussed DC performance and RF performance of dual gate EE-mode pHEMT. And we explained the disadvantage of EE-mode pHEMT power performance. In chapter four, we discussed DC、RF and power performance of dual gate ED-mode pHEMT. And we also compared DC、RF and power performance of EE-mode pHEMT and ED-mode pHEMT . In chapter five, we used EE-mode pHEMT and ED-mode pHEMT to design a 2.4GHz microwave amplifier. In the final chapter, we summarized the results in this thesis.
