서강대학교

초록/요약 도움말

In this paper, the high efficiency and high linearity power amplifier using varactor based tunable matching network (VMN) is presented. First, we designed high efficiency power amplifier for using tunable matching network. The harmonic tuning technique was used to design a high efficiency power amplifier. The harmonic load-pull simulation was performed for harmonic tuning technique. The fabricated power amplifier shows the maximum power added efficiency (PAE) of 80.9 % at output power of 38.6 dBm. The operating frequency of the fabricated power amplifier is 1.85 GHz. We also analyzed the configuration of varactor based tunable matching network for improved performance. In simulation result, we verified that the performance of tunable matching network related with voltage level at varactor diode. We designed two tunable matching networks using anti-series configuration to vary voltage level at varactor diode. The designed tunable matching networks are operating as parallel resonance circuit. The varactor diode was used as capacitor for parallel resonance. The measurement results of two tunable matching networks show low power loss and high linearity because of low voltage level at varactor diode. After the analysis of tunable matching network, we redesign the output matching network of designed power amplifier to integrate tunable matching network for dynamic load modulation technique. In integrated procedure, varactor diode should be operated at low voltage level. The new production of power amplifier using varactor based tunable matching network was fabricated. The measurement results show 10 % enhancement of power added efficiency(PAE) at 10 dB back-off by using tunable matching network. The maximum PAE is 75.7 % at 37.7 dBm of output power. W-CDMA signal with PAR of 8.5 dB was used for measurement for proposed load modulated PA. Using DLM technique, PAE of 38 % at average output power of 28.5 dBm was achieved with ACLR of -30 dBc. Enhanced efficiency of 10 % at average output power of 28.5 dBm has been achieved.