Power Amplifier Integrated With Bandpass Filter for Long Term Evolution Application

This letter presents a high-power amplifier (PA) matched by bandpass filter (BPF) for long term evolution (LTE) applications. The phase shift of the BPF is found to retain ±90° at the working frequency. It can be employed as the output impedance transformer which transforms 50 Ω to the desired maximum power point. By using this method, the high-PA integrated with the BPF avoids extreme wide line and obtain three functions which could boost the radio signal, select the working frequency band and eliminate the harmonics at the same time. The system dimensions are consequently reduced as the following BPF after PA is omitted. A high-PA matched by BPF working at 2.6 GHz is designed. The analysis is given and the measured results and comparisons are presented. The good agreement confirms the validity of the proposed method.