Skip to main content Accessibility help

Evaluation of GaN-HEMT power amplifiers using BST-based components for load modulation

  • Mhd. Tareq Arnous (a1), Alex Wiens (a2), Paul Saad (a1), Sebastian Preis (a1), Zihui Zhang (a1), Rolf Jakoby (a2) and Georg Boeck (a1) (a3)...


In this paper, the concept of load-modulated power amplifiers (PAs) is studied. Two GaN-HEMT power amplifiers (PAs), targeted for high efficiency at maximum and output back-off (OBO) power levels, are designed, implemented, and tested across 1.8–2.2 GHz. The load modulation in the first design is realized by tuning the shunt capacitors in the output matching network. A novel method is employed in the second design, where barium–stronrium–titante is used for the realization of load modulation. The large-signal measurement results across the desired band show 59–70% drain efficiency at 44–44.5 dBm output power for both designs. Using the available tunable technique, the drain efficiency of the PAs is enhanced by 4–20% at 6 dB OBO across the bandwidth.


Corresponding author

Corresponding author: M. T. Arnous Email:


Hide All
[1]Cisco Visual Networking Index: Global Mobile Data Traffic Forecast update 2011–2016 in White Paper, CISCO, (2012), online available:
[2]Cripps, S.C.: RF Power Amplifiers for Wireless Communications, Artech House, Norwood, 2006.
[3]Colantonio, P.; Giannini, F.; Limiti, E.: High Efficiency RF and Microwave Solid State Power Amplifiers, Wiley, Tor Vergata, 2009.
[4]Misra, K.: Radio-Frequency and Microwave Communication Circuits Analysis and Design, Wiley, New York, 2002.
[5]Sobol, H.; Tomiyasu, K.: Milestones of microwaves. IEEE Trans. Microw. Theory Tech., 50 (3) (2002), 594611.
[6]Raab, F.: Intermodulation distortion in Kahn-technique transmitters. IEEE Trans. Microw. Theory Tech., 44 (12) (1996), 22732278.
[7]Raab, F. et al. : Power amplifiers and transmitters for RF and microwave. IEEE Trans. Microw. Theory Tech., 50 (3) (2002), 814826.
[8]Fager, C.; Gustavsson, U.; Nemati, H.; Zirath, H.: High efficiency modulation of switched mode LDMOS power amplifiers, in Proc. 12th Int. Symp. Microwave and Optical Technology, Rome, 2007.
[9]Doherty, W.: A new high efficiency power amplifier for modulated waves. Proc. Inst. Radio Eng., 24 (9) (1936), 11631182.
[10]Brown, E.R.: RF-MEMS switches for reconfigurable integrated circuits. IEEE Trans. Microw. Theory Tech., 46 (11) (1998), 18681880.
[11]Nemati, H.; Fager, C.; Gustavsson, U.; Jos, R.; Zirath, H.: Design of varactor-based tunable matching networks for dynamic load modulation of high power amplifiers. IEEE Trans. Microw. Theory Tech., 57 (5) (2009), 11101118.
[12]Nath, J. et al. : An electronically tunable microstrip bandpass filter using thin-film barium–strontium–titanate (BST) varactors. IEEE Trans. Microw. Theory Tech., 53 (9) (2005), 27072712.
[13]Bengtsson, O. et al. : Discrete tunable RF-power GaN-BST transistors, in Eur. Microwave Conf., (EuMW), Amsterdam, 2012.
[14]Fu, J.; Mortazawi, A.: Improving power amplifier efficiency and linearity using a dynamically controlled tunable matching network. IEEE Trans. Microw. Theory Tech., 56 (12) (2008), 32393244.
[15]Arnous, M.T.; Wiens, A.; Preis, S.; Maune, H.; Bathich, K.; Nikfalazar, M.; Jakoby, R.; Boeck, G.: Load-modulated GaN power amplifier implementing tunable thick film BST components, in Eur Microwave Integrated Circuits Conf. (EuMIC), Nuremberg, 2013.
[16]CGH40025 data sheet. Online available:
[17]Menesklou, W.; Paul, F.; Zhou, X.; Elsenheimer, H.; Binder, J.; Ivers-Tiffee, E.: Nonlinear ceramics for tunable microwave devices part I, materials properties and processing. Microsyst. Technol., 17 (2) (2011), 203211.
[18]Maune, H.; Sazegar, M.; Zheng, Y.; Zhou, X.; Giere, A.; Scheele, P.: Nonlinear ceramics for tunable microwave devices. Microsyst. Technol., 17 (2) (2011), 213224.
[19]Zhou, X. et al. : Characterization of metal (Fe, Co, Ni, Cu) and fluorine codoped barium strontium titanate thick-films for microwave applications. J. Electroceram., 24 (4) (2010), 345354.
[20]Frickey, D.: Conversions between S, Z, Y, H, ABCD, and T parameters which are valid for complex source and load impedances. IEEE Trans. Microw. Theory Tech., 42 (2) (1994), 205211.
[21]Wiens, A. et al. : Load modulation for high power applications based on printed ceramics, in IEEE MTT-S Int. Microwave Symp. Digest (IMS), Seattle, 2013.
[22]Wiens, A.; Bengtsson, O.; Maune, H.; Sazegar, M.; Heinrich, W.; Jakoby, R.: Thick-film barium-strontium-titanate vatactors for RF power transistors, in Eur Microwave Integrated Circuits Conf. (EuMIC), Nuremberg, 2013.



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed