S波段大功率、高效率GaN HEMT器件研究

基于国产的SiC衬底GaN外延材料,研制出大栅宽GaN HEMT单胞管芯。通过使用源牵引和负载牵引技术仿真出所设计模型器件的输入输出阻抗,推导出本器件所用管芯的输入输出阻抗。使用多节λ/4阻抗变换线设计了宽带Wilkinson功率分配/合成器,对原理图进行仿真,优化匹配网络的S参数,对生成版图进行电磁场仿真,通过LC T型网络提升管芯输入输出阻抗。采用内匹配技术,成功研制出铜-钼-铜结构热沉封装的四胞内匹配GaN HEMT。在频率为2.7～3.5 GHz、脉宽为3 ms、占空比为50%、栅源电压Vgs为-3 V和漏源电压Vds为28 V下测试器件,得到最大输出功率Pout大于100 W(50 dBm),PAE大于47%,功率增益大于13 dB。

Study of S-Band GaN HEMTs with High Power and High Efficiency

Based on the GaN epitaxial wafer with domestic SiC substrates,the unit cell of the GaN HEMT with the large gate width was designed.The input and output impedances of the designed model device were simulated with the source-pull and load-pul technologies,and the input and output impedances of the unit cell were deduced.The wide-band Wilkinson power divider was designed with the λ/4 multi-section impedance transformation lines,and simulated for the principle diagram.The S-parameters of the matching net were optimized,and the electromagnetic field simulation was carried out for the layout.The input and output impedances were increased by the LC T-net.The four-cell internally matched GaN HEMT device with the Cu-Mo-Cu heat sink was fabricated by the intermatching technology.At Vgs=-3 V and Vds=28 V,the maximum output power is more than 100 W(50 dBm),the power gain is more than 13 dB and the power added efficiency is more than 47% on the conditions of 2.7-3.5 GHz frequency,3 ms pulse width and 50% duty cycle.