| The power amplifier is an important part for Beidou radio frequency transmitters and it has a significant impact on the quality of communication,dissipation and reliability of the equipments,so it's important to research and design a high performance Beidou I power amplifier.In this thesis,a power amplifier for Beidou I transmitters is designed with the balanced amplifier structure,based on the GaAs pHEMT device and the SiP technology.It has high gain,high efficiency,small size and anti-mismatch capability,which is suitable for Beidou navigation equipments,especially for Beidou handheld terminals.This thesis first introduces the principle and method of power amplifier design,including the principles and characteristics of GaAs pHEMT devices used in power amplifiers,the parameter of power amplifiers,the methods of loadpull and the principles and characteristics of balanced amplifiers.And then according to the specifications,a power amplifier topology is developed and the circuit is designed and simulated.The simulation work includes two stages of amplifier circuit,active bias circuit,matching circuit and 3dB directional coupler circuit,and then the overall circuit is simulated in consideration of the circuits' parasitic parameters.Then the layout of power amplifier die and substrate are designed,after which the packaged power amplifier module is fabricated.Finally,the test method of the power amplifier is introduced,and the power amplifier is tested.The test results shows that the power amplifier works stablely and it is neither self-excited nor broken down when the load is mismatched.Also it has no spurious.In the work band of 1616±4.08MHz,the power amplifier has a 33.5dB power gain,1.3 VSWR,38.5dBm output power,50.4%efficiency.Its second and third harmonic distortion is-45.3 dBc and-55.6 dBc respectively.The size of packaged module is 8×8×1 mm. |
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