Study On Broadband Power Amplifier Based On Silicon Carbide MESFET

As the result of the development of modern wireless communication technologies,more and more requirements,such as wider bandwith,higher output power and so on, have been proposed for the RF power amplifier.The broadband power amplifier based on silicon carbide MESFET have an enormous potential for being used in the active phased array radar,satellite communication, and electronic warfare, due to the features of the SiC MESFET of high saturation electron velocity, high breakdown voltage,low output capacitance,high operating temperature and high thermal conductivity and other characteristics.In this thesis, a two-stage broadband power amplifier has been designed using the CRF-24060 of the CREE company.Firstly the basic theory of the power amplifier has been given.Because of the compromise between the linearity and the efficiency ,class AB mode has been chosen to this broadband power amplifier.Meanwhile the restrictions of broadband matching and the methods to expand the bandwith of the matching circuit have been introduced in detail.And then the full design procedure of this broadband power amplifier has been discussed.At last, the results of simulation to the whole circuit has been showed. In the band of 500 MHz-2000 MHz, the small signal gain of 27dB, and stability factor K> 2.7, the power gain of 25.9dB, gain flatness of , output power of more than 45.9dBm (38.9W), power added efficiency PAE> 15%,have been obtained;at the same time ,at 1500 MHz,the simulation results are power gain of 26dB, 1dB output power of 46dBm (40W), power added efficiency PAE up to 36%, third order intermodulation coefficient IMD3 =- 24dBc, fifth-order intermodulation factor IMD5 =- 39dBc.In the end, the PCB layout of the full circuit has been given.