Designing a more efficient broadband 100 W Doherty power amplifier for cellular base-stations: Page 4 of 5

October 10, 2016 //By X Moronval, J Gajadharsing, Ampleon
The proliferating frequency bands and modulation schemes used in modern cellular networks are making it increasingly important that the RF power amplifiers used in base-stations offer the right combination of output power, multiband support and efficiency – at both peak and average power outputs.

Implementing the new topology

The new iDPA topology is implemented by mounting two iDPA dies in a dual-path air-cavity plastic package, on a low-cost industry-standard PCB. The external dimensions are 50- x 80-mm, and the effective area excluding connectors and screws is less than 10 cm2 (Figure 5).

Figure 5: Fabricated fixture of the 100 W four-way iDPA (source: Ampleon).

This highly integrated four-way Doherty amplifier offers 13.4 dB gain, as well as an average efficiency of 46 to 48% at 8 dB output back-off from the 100 W peak power output, across a frequency range of 1.805 to 2.17 GHz – which is close to a 20% fractional bandwidth.