Skip to main content Accessibility help

RF-DC conversion efficiency improvement for microwave transmission with pulse modulation

  • Takashi Hirakawa (a1), Ce Wang (a1) and Naoki Shinohara (a1)


Microwave power transfer (MPT) can solve certain types of problems. For example, Internet of Things requires a flexible configuration of sensor networks, which is hindered by wired-charging sensors. This problem can be overcome by MPT techniques. However, the transmission efficiency of MPT is lower than that of wired transmission. This study focuses on the operation of rectifiers having a pulse-modulated input signal. Although a pulse-modulated wave is effective for improving the RF-DC conversion efficiency, the output voltage waves of rectifiers have a high ripple content. Moreover, the harmonic balance method cannot be used to simulate the operation of a pulse-modulated rectifier. To reduce the ripple content, a smoothing capacitor should be connected in parallel to an output load. We investigated the influence of a smoothing capacitor, the general characteristics of rectifiers under pulse-modulated waves, and the effectiveness of using pulse-modulated waves for improving RF-DC conversion efficiency. In conclusion, we reveal a necessary condition of the smoothing capacitor for improvement, demonstrate the effectiveness of pulse modulation, and show that the optimum impedance with a pulse-modulated wave input is an inverse of duty ratio times as compared to that with continuous wave input.


Corresponding author

Corresponding author: Takashi Hirakawa Email:


Hide All
[1]Brown, W.: Experiments in the transportation of energy by microwave beam. In IRE International Convention Record, IEEE12, 1966, 817.
[2]Brown, W.C.: The history of power transmission by radio waves. IEEE Trans. Microwave Theory Technol., 32 (9) (1984), 12301242.
[3]Shinohara, N.: Simultaneous WPT and wireless communication with TDD algorithm at same frequency band. In Georgiadis, A.; Nikoletseas, S.; Yang, Y.: editor, Wireless Power Transfer Algorithms, Technologies and Applications in Ad Hoc Communication Networks, chapter 9, Springer, 7 2016, 211230.
[4]Claessens, S.; Schreurs, D.; Pollin, S.: SWIPT with biased ask modulation and dual-purpose hardware. In Wireless Power Transfer Conference (WPTC), 2017 IEEE, IEEE, 2017, 14.
[5]Claessens, S.; Pan, N.; Rajabi, M.; Schreurs, D.; Pollin, S.: Enhanced biased ask modulation performance for SWIPT with AWGN channel and dual-purpose hardware. IEEE Trans. Microwave Theory Technol., 66 (2018), 34783486.
[6]Matsumoto, H.; Takei, K.: An experimental study of passive uhf RFID system with longer communication range. In Microwave Conference, 2007. APMC 2007. Asia-Pacific, IEEE, 2007, 14.
[7]Nahas, J.J.: Modeling and computer simulation of a microwave-to-dc energy conversion element. IEEE Trans. Microwave Theory Technol., 23 (12) (1975), 10301035.
[8]Boyakhchyan, G.P.; Vanke, V.; Lesota, S.K.; Maslovskiy, F.N.; Novitskiy, V.A.: Analytical calculation of a high-efficiency microwave rectifier employing a Schottky-barrier diode. Telecommun. Radio Eng., 37 (10) (1983), 6466.
[9]Guo, J.; Zhang, H.; Zhu, X.: Theoretical analysis of RF-DC conversion efficiency for class-f rectifiers. IEEE Trans. Microwave Theory Technol., 62 (4) (2014), 977985.
[10]McSpadden, J.O.; Fan, L.; Chang, K.: Design and experiments of a high-conversion-efficiency 5.8-GHz rectenna. IEEE Trans. Microwave Theory Technol., 46 (12) (1998), 20532060.
[11]Yoo, T.-W.; Chang, K.: Theoretical and experimental development of 10 and 35 GHz rectennas. IEEE Trans. Microwave Theory Technol., 40 (6) (1992), 12591266.
[12]Boaventura, A.; Belo, D.; Fernandes, R.; Collado, A.; Georgiadis, A.; Carvalho, N.B.: Boosting the efficiency: unconventional waveform design for efficient wireless power transfer. IEEE Microwave Mag., 16 (3) (2015), 8796.
[13]Collado, A.; Georgiadis, A.: Improving wireless power transmission efficiency using chaotic waveforms. In Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International, IEEE, 2012, 13.
[14]Lo, C.-C.; Yang, Y.-L.; Tsai, C.-L.; Lee, C.-S.; Yang, C.-L.: Novel wireless impulsive power transmission to enhance the conversion efficiency for low input power. In Microwave Workshop Series on Innovative Wireless Power Transmission: Technologies, Systems, and Applications (IMWS), 2011 IEEE MTT-S International, IEEE, 2011, 5558.
[15]Carvalho, N.B.; Remley, K.A.; Schreurs, D.; Card, K.G.: Multisine signals for wireless system test and design [application notes]. IEEE Microwave Mag., 9 (3) (2008), 122138.
[16]Collado, A.; Georgiadis, A.: Optimal waveforms for efficient wireless power transmission. IEEE Microwave Compon. Lett., 24 (5) (2014), 354356.
[17]Ibrahim, R. et al. : Novel design for a rectenna to collect pulse waves at 2.4 GHz. IEEE Trans. Microwave Theory Technol., 66 (1) (2018), 357365.
[18]Moré, J.J.: The Levenberg–Marquardt algorithm: implementation and theory. In Numerical Analysis, Springer, 1978, 105116.



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