1. 微波電路期中報告 論文研討 : Experimental Design Method for GHz-Band High- Efficiency Power Amplifiers Based on MHz-Band Active Harmonics Load-Pull Technique Ryo Ishikawa, Yoichiro Takayama, Kazuhiko Honjo Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012 報告人 : 碩研電子一甲 MA130220 柯慶宏 Southern Taiwan University Department of Electronic Engineering

2. Introduction 1 Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012 Ryo Ishikawa, Yoichiro Takayama, Kazuhiko Honjo Fig. 1 (a) shows the load configuration of a high-efficiency amplifier. A transistor can be modeled with parasitic elements and with a nonlinear current source that does not relate to a frequency. The reactive parasitics can be ignored at the MHz-band. Then, the optimum load impedance for a transistor without reactive parasitics can be estimated in the MHz-band by using a simple active load-pull system, as shown in Fig. 1 (b). Therefore, in the GHz-band, the optimum impedance outside the transistor can also be estimated by considering the reactive parasitics.

3. MHZ-BAND ACTIVE LOAD-PULL SYSTEM 2 Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012 Ryo Ishikawa, Yoichiro Takayama, Kazuhiko Honjo Fig. 1. Principle of optimum load impedance estimation for high-efficiency power amplifiers. (a) Circuit configuration of the high-efficiency amplifier. (b) Active load-pull system including harmonics at a MHz band to obtain ZLopt.

4. 3 Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012 Ryo Ishikawa, Yoichiro Takayama, Kazuhiko Honjo

5. 4 Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012 Ryo Ishikawa, Yoichiro Takayama, Kazuhiko Honjo Fig. 3. Measured voltage and current waveforms at the HEMT and load impedance conditions for each operation. (a) A class-F operation. (b) A capacitive element is added at the fundamental frequency. (c) An inductiveelement is added at the fundamental frequency.

6. 5 Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012 Ryo Ishikawa, Yoichiro Takayama, Kazuhiko Honjo REACTIVE PARASITICS ESTIMATION Fig. 4. (a) Schematic drawing of circuit-impedance estimation. (b) Measured susceptance at the output side of the HEMT and target impedance for a 1.9 GHz operation.

7. 6 GHZ-BAND LOAD CIRCUIT DESIGN Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012 Ryo Ishikawa, Yoichiro Takayama, Kazuhiko Honjo Fig. 5. Fabricated amplifier designed at 1.9 GHz Fig. 6. EM simulated (left) and measured (right) circuit impedance characteristics for the load circuit

8. 7 Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012 Ryo Ishikawa, Yoichiro Takayama, Kazuhiko Honjo Fig. 7. Measured waveforms and load impedance in the 20MHz active load-pull system for the measured impedance at 1.88 GHz Fig. 8. Measured input-output power response and efficiency characteristics

9. CONCLUSION 8 An experimental design method for GHz-band highefficiency power amplifiers based on a MHz-band active loadpull technique that includes harmonics tuning was introduced. Using this method, a load circuit design depending on the specific properties of the transistor can be achieved. For an InGaAs/GaAs HEMT, a load circuit at 1.9 GHz has been designed and fabricated based on a 20-MHz-band active loadpull evaluation, by taking parasitic elements into consideration.. A maximum drain efficiency of 77% was obtained at 1.88 GHz, which is very close to the design prediction. Proceedings of APMC 2012, Kaohsiung, Taiwan, Dec. 4-7, 2012 Ryo Ishikawa, Yoichiro Takayama, Kazuhiko Honjo

10. 9 Experience 關於這篇作者所提出的一個實驗的設計方法，為 5GHz 頻帶高 效率功率放大器在 MHzband 有源負載拉移技術，包括諧波調 整。 其實看到後面還是看不懂他們設計出來的這個方法能應用在 什麼地方。