Design of Wideband Power Amplifier for Small Cell Applications

In this research, Chebyshev type of low-pass impedance transformation network is chosen as the matching structure for the design of broadband class C power amplifiers (PAs) which can cover LTE Band I to Band IV. To approximate inductors and capacitors in the low pass transformation network, high- and low- impedance microstrip lines are used in the all-distributed matching type of PA, and high CPWG(coplanar waveguide with ground) and SMD 0402 capacitors are used in the semi-lumped matching type of PA. With similar first order input and output impedances between the two matching types of PAs, the experiment results show that both of the PAs are realized from 1.4 to 2.6 GHz(60%) with a measured drain efficiency of 50%-75% and output power of 25-29 dBm. The semi-lumped matching type of PA has better harmonic suppression than the all-distributed matching type of PA, and furthermore, the area of the semi-lumped matching type of PA circuit is smaller than the one of the all-distributed matching type of PA by 91%.