Design of a Miniaturized High Power DPA for 4GHz

The Doherty power amplifier based of GaN HEMT which was applied for 4GHz band was designed and implemented, and the symmetrical Doherty structure was used. The power chip and matching circuit of the main power amplifier were as same as the auxiliary power amplifier. The ceramic chip was used. The whole system was integrated into 23.00mm*21.70mm tube shell by means of ceramic chip and gold wire connection, which improved the integration of Doherty power amplifier. The test results showed that the saturated output power could reach more than 48 dBm, and the drain efficiency of saturated output was more than 55%. Moreover, the drain efficiency was more than 50% when the output power was fell back 6 dBm. Compared with the balanced AB amplifier, the Doherty PA had obvious advantages. In addition, the performance about IMD3 of Doherty was better than that of balanced class AB amplifier in the regression region.