The Study And Design Of Class-F High Efficiency Power Amplifier

The transmitter is the indispensable part of the communication system,and the power amplifier is the key component of the whole transmitter.The efficiency of power amplifier is an important technique Data.By reducing the conduction angle to improve the efficiency is the traditional way,which can not be adapted to the needs of the development of communication systems nowadays.Class-F or Inverse Class-F power amplifier can improve the efficiency by harmonic control,which became a hotspot and focus of the study of power amplifier at the present.First of all,the basic theory and method which should be followed in the design process of power amplifier are introduced in this thesis.As regard to the power amplifier,the concept of power matching is leaded and the technique of load-pull is also introduced.At last,the loadline theory is used to explain the output power contour.The third chapter gives full consideration to the effects of transistor parasitic parameters,All harmonic impedances can be acquired by utilizing Source-pull and Load-pull in ADS simulation software.The second harmonic has been treated in the input circuit to decrease the influence of parasitic parameters of tube itself,which leads to the distortion of input signal.In the output circuit the parasitic compensation circuit combined with the harmonic impedance control network has been utilized to control second and three harmonic,which enhances the efficiency of the power amplifier.Second harmonic attunement line and dc bias line are shared,reducing the area of the circuit.Using a fan-shaped microstrip constitutes a communication terminal short circuit makes up the deficiency of tolerance of the actual capacitance.Measured results show that in the frequency of 2.4 GHz power additional efficiency(PAE)is 72.5% and the maximum power is 40.2 dBm,at the same time the Gain can maintain 14.2 dB,which indicates that the Class-F power amplifier has good performance.Chapter four is focused on the dual and broad band Class-F/IF power amplifier.Firstly,two different output harmonic control circuits are proposed.As for the conflict problem of frequency of dual band Class-F amplifier,Class-F/IF mixed mode dual band amplifiers are designed.But to some extent,some difficulty in the design process are not deal with.For example,high frequency third harmonic is far away from second harmonic of low frequency,so the difference of parasitic parameters is bigger,failing to realize good short circuit design in drain inside the transistor.lead to the corresponding higher harmonic load,which makes the output power of the amplifier failed to present the obviously dual band features perfectly,but the efficiency is dual band obviously.So it also can proved that this design method can improve the efficiency of power amplifier.At last,an X-band GaN amplifier has been designed based on continuous F theory by software simulation.The measured results satisfy the target.