The main design points of a power amplifier are focused on output power and efficiency of power amplifier. One of the methods to improve the output power and efficiency is to terminate the harmonics at the output. Among the harmonics, the second harmonic is especially in want of tuning, because its magnitude is relatively larger than the other harmonics. Many works have been reported for harmonic termination.
In this thesis, high efficiency power amplifier was designed with harmonic suppression transmission line. The harmonic suppression transmission line can suppress the n-th harmonic output. The harmonic suppression transmission lines consist of π-type transmission line with two λ/4n open stub and T-type transmission line with one λ/4n open stub. Experimental results show that this transmission line has wide stop-band and good pass band characteristics.
In order to verify the improvement of the harmonic suppression transmission line amplifier, harmonic suppression transmission line amplifier was compared normal amplifier. As the result of measurement, the output power and of the harmonic suppression transmission line amplifier were improved as 0.2～1.6 dB. PAE(Power Added Efficiency) were improved as 17%. Besides, all the harmonics were suppressed.
And the balanced amplifier designed with harmonic suppression coupler. As the result of measurement, the output power and of the balanced amplifier using harmonic suppression coupler were improved as 0.1～1.64 dB. PAE(Power Added Efficiency) were improved as 11%.