关键词: 缺陷地, 功率放大器, 特征阻抗, 二次谐波, 功率附加效率

Abstract: The paper presents the effects of defected ground structure (DGS) on different ground planes in RF power amplifiers (PAs). Two DGS patterns etched on the front and back planes of printed circuit board which are named Top-DGS and Bottom-DGS, and a thru microstrip line is manufactured and measured to compare the insert loss at the fundamental and second harmonic frequencies. In order to evaluate the effects of the Top-DGS, Bottom-DGS and without DGS on the PA, three 4 W PAs have been designed and measured. Measured results show that the PA with the Top-DGS can reject the second harmonic about 13 dB at the output power of 34.76 dBm, and achieve better the output power and power added efficiency (PAE) than the one without DGS; the one with the Bottom-DGS has the suppression of about 28 dB for the second harmonic at the output power of 34.21 dBm, and has less the output power and PAE for the decreased characteristic impedance of DGS pattern.

Key words: defected ground structure, power amplifiers, characteristic impedance, second harmonic, power added efficiency