A precise model of the parasitic network for the widely used CGH40010F transistor has been derived and reported by Tasker and Benedikt.12 Based on this parasitic network model, the impedance trajectories in the Smith chart at I-gen and at the package plane of the output matching network are shown in Figure 4. The derived fundamental impedances at the current plane across the operating band from 0.5 to 2.3 GHz are in or near the theoretic region.
The final design of the resistive-reactive SCFM PA is shown in Figure 5. Simulated and measured results with a CW input power of 29 dBm are shown in Figure 6. A drain efficiency of 59 to 79 percent and saturated output power of 39.4 to 41.6 dBm are achieved across the band from 0.5 to 2.3 GHz. The measured results are consistent with the simulations.
To characterize linearity, a 20 MHz LTE signal with a peak-to-average power ratio of about 7.5 dB was used to drive the PA at 0.8, 1, 1.6 and 2 GHz. As shown in Figure 7, the broadband PA exhibits good linearity at about 5 dB back-off power, where the adjacent channel leakage power ratio (ACLR) is lower than −30 dBc, with 34.1 to 49.1 percent average efficiency. Table 1 compares the performance of this PA with other similar state-of-the-art broadband PAs.
The resistive-reactive SCFM design space was extended by introducing the third harmonic impedance. Using this methodology, the overlap between the fundamental and harmonic impedances was effectively solved, and a broadband high efficiency PA was designed, built and tested. The agreement between simulation and measurement demonstrates the validity of this approach for a multi-octave, high efficiency PA. Driven by 20 MHz LTE signals, the ACLR of the proposed PA is lower than −30 dBc at approximately 35 dBm output power, with average drain efficiency higher than 34 percent.
This research was supported by the Natural Science Foundation of China under grant 61501455, Natural Science Foundation of Beijing Municipality under grant 4162068 and National Defense and Technology Innovation Foundation of Chinese Academy of Sciences under grant CXJJ-16M124.
- S. C. Cripps, P. J. Tasker, A. L. Clarke, J. Lees and J. Benedikt, “On the Continuity of High Efficiency Modes in Linear RF Power Amplifiers,” IEEE Microwave & Wireless Components Letters, Vol. 19, No. 10, October 2009, pp. 665–667.
- P. Wright, J. Lees, J. Benedikt, P. J. Tasker and S. C. Cripps, “A Methodology for Realizing High Efficiency Class-J in a Linear and Broadband PA,” IEEE Transactions on Microwave Theory & Techniques, Vol. 57, No. 12, December 2009, pp. 3196–3204.
- J. Chen, S. He, F. You, R. Tong and R. Peng, “Design of Broadband High-Efficiency Power Amplifiers Based on a Series of Continuous Modes,” IEEE Microwave & Wireless Components Letters, Vol. 24, No. 9, September 2014, pp. 631–633.
- V. Carrubba, J. Lees, J. Benedikt, P. J. Tasker and S. C. Cripps, “A Novel Highly Efficient Broadband Continuous Class-F RFPA Delivering 74% Average Efficiency for an Octave Bandwidth,” IEEE MTT-S IMS Digest, June 2011.
- V. Carrubba, A. L. Clarke, M. Akmal, Z. Yusoff, J Lees, J. Benedikt, S. C. Cripps and P. J. Tasker, “Exploring the Design Space for Broadband PAs Using the Novel ‘Continuous Inverse Class-F Mode’,” 41st European Microwave Conference, October 2011.
- W. Shi, S. He and Q. Li, “A Series of Inverse Continuous Modes for Designing Broadband Power Amplifiers,” IEEE Microwave & Wireless Components Letters, Vol. 26, No. 7, July 2016, pp. 525–527.
- Z. Lu and W. Chen, “Resistive Second-Harmonic Impedance Continuous Class-F Power Amplifier with Over One Octave Bandwidth for Cognitive Radios,” IEEE Journal on Emerging & Selected Topics in Circuits & Systems, Vol. 3, No. 4, December 2013, pp. 489–497.
- C. Friesicke, R. Quay and A. F. Jacob, “The Resistive-Reactive Class-J Power Amplifier Mode,” IEEE Microwave & Wireless Components Letters, Vol. 25, No. 10, October 2015, pp. 666–668.
- Q. Li, S. He, Z. Dai and W. Shi, “A Method for Designing Generalized Continuous Power Amplifier,” IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications, July 2016.
- N. Tuffy, L. Guan, A. Zhu and T. J. Brazil, “A Simplified Broadband Design Methodology for Linearized High Efficiency Continuous Class-F Power Amplifiers,” IEEE Transactions on Microwave Theory & Techniques, Vol. 60, No. 6, March 2012, pp. 1952–1963.
- J. Moon, J. Kim and B. Kim, “Investigation of a Class-J Power Amplifier With a Nonlinear Cout for Optimized Operation,” IEEE Transactions on Microwave Theory & Techniques, Vol. 58, No. 11, November 2010, pp. 2800–2811.
- P. J. Tasker and J. Benedikt, “Waveform Inspired Models and the Harmonic Balance Emulator,” IEEE Microwave Magazine, Vol. 12, No. 2, April 2011, pp. 38–54.