**5. Conclusion**

In this chapter, GaN-based power amplifiers for wireless communication infrastructure have been discussed. GaN HEMT's offer superior performance compared to state-of-the-art power devices for base station power amplifiers e.g. LDMOS. Especially high power density and high supply voltage of GaN HEMT's leads to smaller size of the device and thus, to lower parasitic capacitance, higher output impedance and large bandwidth which are advantageous for switched-mode and reconfigurable power amplifiers. In addition, wide range of operating frequency can be covered by GaN-based power devices. The concerns of GaN transistors regarding charge carrier trapping and reliability is gradually extenuated by the progress in GaN device technology.

Device modelling is another important issue which ensures the power amplifier design community fast design process and accurate simulations. As examples, VHF class E amplifier and 2.45 GHz class AB amplifier have been presented.
