Improvement in Performance of Power Amplifiers by Defected Ground Structure

SUMMARY This paper describes the performance improvement of power amplifiers by defected ground structure (DGS). Due to the excellent capability of harmonic rejection and tuning, DGS plays a great role in improving the major nonlinear behaviors of power amplifier such as output power, harmonics, power added efficiency (PAE), and the ratio between the carrier and the third order intermodulation distortion (C/IMD3).In order to verify the improvement of performances by DGS, measured data for a power amplifier, which adopts a 30 Watts LDMOS device for the operation at 2.1–2.2 GHz, are illustrated under several operating bias currents for two cases, i.e., with and without DGS attached.The principle of the improvement is described by the simple Volterra nonlinear transfer functions with the consideration of different operating classes.The obtained improvement of the 30 Watts power amplifier, under 400 mA of IdsQ as an example, includes the reduction in the second and third harmonics by 17 dB and 20 dB, and the increase in output power, PAE, and C/IMD3 by 1.3 Watts, 3.4%, and 4.7 dB, respectively.

[1]  E. Camargo,et al.  A compact high power amplifier for handy phones , 1994, 1994 IEEE MTT-S International Microwave Symposium Digest (Cat. No.94CH3389-4).

[2]  J.-E. Mueller,et al.  A 3V small chip size GSM HBT power MMIC with 56% PAE , 2000 .

[3]  Hyo-Kun Hahn,et al.  High-Efficiency 1-, 2-, and 4-W Class-B FET Power Amplifiers , 1986 .

[4]  Tatsuo Itoh,et al.  A uniplanar compact photonic-bandgap (UC-PBG) structure and its applications for microwave circuit , 1999 .

[5]  John L. B. Walker,et al.  High-Power GaAs FET Amplifiers , 1993 .

[6]  Jong-Sik Lim,et al.  A power amplifier with efficiency improved using defected ground structure , 2001 .

[7]  J. Obregon,et al.  High-efficient class F GaAs FET amplifiers operating with very low bias voltages for use in mobile telephones at 1.75 GHz , 1993, IEEE Microwave and Guided Wave Letters.

[8]  Jae-Bong Lim,et al.  A novel 1-D periodic defected ground structure for planar circuits , 2000 .

[9]  Tatsuo Itoh,et al.  Broad-band power amplifier using dielectric photonic bandgap structure , 1998 .

[10]  Jose C. Pedro,et al.  Two-tone IMD asymmetry in microwave power amplifiers , 2000, 2000 IEEE MTT-S International Microwave Symposium Digest (Cat. No.00CH37017).

[11]  Y. Qian,et al.  A design of the low-pass filter using the novel microstrip defected ground structure , 2001 .

[12]  N.B. de Carvalho,et al.  Large signal IMD sweet spots in microwave power amplifiers , 1999, 1999 IEEE MTT-S International Microwave Symposium Digest (Cat. No.99CH36282).

[13]  Andrey S. Andrenko,et al.  Application of PBG microstrip circuits for enhancing the performance of high‐density substrate patch antennas , 2002 .

[14]  F. E. Gardiol,et al.  Improvement of a Class-C Transistor Power Amplifier by Second-Harmonic Tuning , 1979 .

[15]  Y. Qian,et al.  High efficiency S-band class AB push-pull power amplifier with wideband harmonic suppression , 2001, 2001 IEEE MTT-S International Microwave Sympsoium Digest (Cat. No.01CH37157).