上海科技大学知识管理系统

This paper reports a high-performance microwave receiver protector (RP) based on a single gallium nitride (GaN) high electron mobility transistor (HEMT) at an operation frequency of 30 to 3000 MHz. The HEMT-based RP exhibits multi features: high power compression, constant output power, tunable threshold power level, and insensitivity to frequency variation. With a low drain voltage (V-ds) of 3 V, constant output power of 9.9 dBm was acquired for input power over its threshold power of 3.2 dBm. Power compression of 13.3 dB was achieved at the input power of P-in = 20 dBm. In addition, adjustable threshold power level P-th could be obtained by merely tuning drain voltage. Transducer gain measurement results were employed to explain the occurrence of output power saturation. Relatively higher P-th was linked to wider gate voltage swing which extended the linear region of the P-out-P-in characteristic. In addition, the GaN HEMT's power compression capability shows great immunity to frequency variation, which is promising for protecting sensitive receiver components at both low and high frequencies. Finally, the phase shift of the GaN HEMT RP at high input power was measured and analyzed by the nonlinear behaviors of input capacitance C-gs.