Gan Device-based Rf Power Amplifier Design

The main work of this thesis is designing a RF power circuit which is based on GaN transistor devices. A broadband matching circuit is proposed in S-band. The transistors used in the circuits are high electron mobility transistors (HEMT) (CGH40010 and CGH40045) of CREE company.The main work is as follows:Firstly, the broadband matching circuits are designed. After analyzing the stability of CGH40010 and CGH40045 GaN HEMT over 2.7GHz～3.5GHz, their static operating points are set up, and the broadband impedance matching circuit is designed. In addition, a balanced two-branch structure consists of taper line is proposed, the simulation and optimization are completed by ADS. The performance meets the following characteristics: the bandwidth 800MHz, the gain in pass-band dB (S (2,1))＞10dB, VSWR1＜2, VSWR2＜2, 3dB compression point output power＞40dBm,46dBm, and efficiency＞40%.Secondly, the bias circuit for the power circuit is designed. Requirements are that positive voltage is controlled by negative voltage, and over-current protection should be considered. With the application of Orcad analog circuit simulation software, the power circuit meeting the requirements has been designed.Finally, using Altium Designer Summer 08 and AutoCAD mapping software, printed circuit board of the power amplifier and bias supply circuits are made. After the tests of hardware circuits, all requirements for the circuits are satisfied.