L-band high efficiency GaN HEMT power amplifier for space application

This paper describes a high efficiency and high output power GaN power amplifier for L-band space application. The power amplifier module was developed using GaN high electron mobility transistor (HEMT) device technology. The Matching Circuits were designed With a large-signal model developed by Cree. The special R-C parallel networks and gate resistance are used for cancellation of self-oscillation of low frequency and radio frequency at input matching circuit and bias circuits. The output impedance of a transistor under high power operation can be obtained by simulated load-pull results, which can be modeled by a parallel circuit of R and C. In the matching Circuit design, step-step impedance transformation matching technology is employed. Under Vds=28V, Vgs=-2.8V, 58W power amplifier achieves a 68% PAE at 1.19GHz under CW operating conditions.