Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/6278
標題: 射頻功率放大器的特性分析
The Analysis of RF Power Amplifier
作者: 張靖輝
關鍵字: Power amplifier;功率放大器;Gain compression mechanisms;Waveform clipping effects;增益壓縮機制;波形截斷效應
出版社: 電機工程學系
摘要: 
由於無線通訊的快速發展,因此展開了對於具有高功率以及良好線性度之功率放大器的大量需求。然而,放大器的輸出功率與線性度會受到某些增益壓縮機制的限制,例如:膝部電壓、夾止電壓、崩潰電壓、最大汲極電流等機制。這些機制會隨著輸入信號功率的持續增加而壓縮增益接而飽和輸出的功率。
輸出波形的截斷效應是造成MESFET增益壓縮的主要原因。而每一個增益壓縮機制會表現出不同的特徵在平均閘極電流與平均汲極電流之上。我們藉由觀察平均閘極電流與平均汲極電流的變化來分析這些機制的發生。在本論文研究中,MESFET的增益壓縮機制在各個偏壓條件下的不同負載阻抗之操作狀況都已作分析。不同負載線的情況將會遭遇到不同的增益壓縮機制。因此,平均閘極電流與平均汲極電流可以被用來判別不同的增益壓縮機制與元件的相關負載線狀況。

The rapid growth of wireless communication has open up the request for high power and good linearity power amplifier. However, the output power and linearity is limited by some gain compression mechanisms, such as knee voltage, pinch-off voltage, breakdown voltage and the maximum drain current. These mechanisms compress constant linear gain and then saturate output power as input power increases.
The waveform clipping effects cause gain compression in MESFETs. Each gain compression mechanism has its own signature in average RF gate and drain currents. We can analyze and identify different gain compression mechanisms by observing the change of average gate current and drain current. In this thesis, the gain compression mechanisms for MESFETs at various bias points with different loadline conditions are analyzed. Different loadline conditions will run into different gain compression mechanisms. Hence, the average RF gate and drain currents can be used to determine different gain compression mechanisms and associated loadlines for our device.
URI: http://hdl.handle.net/11455/6278
Appears in Collections:電機工程學系所

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