In this paper, a novel circularly polarized rectenna, with a harmonic suppression, capable of harvesting low-power RF energy with wide operating output loads is presented. The proposed rectenna is composed of a circularly polarized CPW-fed antenna based on a split ring resonator (SRR) and a wideband rectifying circuit. The circular polarization characteristic is achieved by breaking the symmetry of the SRR. The designed topology is fabricated and measured. Simulated and measured results show that the rectenna's efficiency is more than 45% at 2.45 GHz with an input power of -15 dBm under different polarizations. Importantly, the measured results show that the proposed configuration can maintain the same efficiency over wide ranges of loads (from 1 to 5 kΩ). The measured output dc voltage of the rectifier with a load resistance of 3-kΩ is 0.21 V and 1.22 V at -15 dBm and 0 dBm, respectively. The proposed design concept is very suitable for the 2.45 GHz ISM band (Wi-Fi, Bluetooth, RFID, etc.).
2. Lin, W. and R. W. Ziolkowski, "Wirelessly powered internet-of-things sensors facilitated by an electrically small Egyptian axe dipole rectenna," Asia-Pacific Microwave Conference Proceedings, APMC, 891-892, Dec. 2019, doi: 10.1109/APMC46564.2019.9038497.
3. Okba, A., A. Takacs, and H. Aubert, "Compact flat dipole rectenna for IoT applications," Progress In Electromagnetics Research C, Vol. 87, 39-49, 2018.
4. Carvalho, A., N. Carvalho, P. Pinho, and R. Gonçalves, "Wireless power transmission and its applications for powering Drones," 8th Congress of the Portuguese Committee of URSI, 2014.
5. Takhedmit, H., L. Cirio, F. Costa, and O. Picon, "Transparent rectenna and rectenna array for RF energy harvesting at 2.45 GHz," 8th European Conference on Antennas and Propagation, EuCAP 2014, 2970-2972, 2014, doi: 10.1109/EuCAP.2014.6902451.
6. Takhedmit, H., Z. Saddi, and L. Cirio, "A high-performance circularly-polarized rectenna for wireless energy harvesting at 1.85 and 2.45 GHz frequency bands," Progress In Electromagnetics Research C, Vol. 79, 89-100, 2017.
7. Lu, P., X. S. Yang, J. L. Li, and B. Z. Wang, "A compact frequency reconfigurable rectenna for 5.2- and 5.8-GHz wireless power transmission," IEEE Trans. Power Electron., Vol. 30, No. 11, 6006-6010, Nov. 2015, doi: 10.1109/TPEL.2014.2379588.
8. Li, X., L. Yang, and L. Huang, "Novel design of 2.45-GHz rectenna element and array for wireless power transmission," IEEE Access, Vol. 7, 28356-28362, 2019, doi: 10.1109/ACCESS.2019.2900329.
9. Palazzi, V., et al., "Design of a ultra-compact low-power rectenna in paper substrate for energy harvesting in the Wi-Fi band," 2016 IEEE Wireless Power Transfer Conference (WPTC), Aveiro, Portugal, Jun. 2016, doi: 10.1109/WPT.2016.7498823.
10. Sun, H., Y. X. Guo, M. He, and Z. Zhong, "Design of a high-efficiency 2.45-GHz rectenna for low-input-power energy harvesting," IEEE Antennas Wirel. Propag. Lett., Vol. 11, 929-932, 2012, doi: 10.1109/LAWP.2012.2212232.
11. Olgun, U., C. Chen, and J. L. Volakis, "Investigation of rectenna array configurations for enhanced rf power harvesting," IEEE Antennas Wirel. Propag. Lett., Vol. 10, 262-265, 2011, doi: 10.1109/LAWP.2011.2136371.
12. Niotaki, K., S. Kim, S. Jeong, A. Collado, A. Georgiadis, and M. M. Tentzeris, "A compact dual-band rectenna using slot-loaded dual band folded dipole antenna," IEEE Antennas Wirel. Propag. Lett., Vol. 12, 1634-1637, 2013, doi: 10.1109/LAWP.2013.2294200.
13. Haboubi, W., H. Takhedmit, J.-D. Lan Sun Luk, S.-E. Adami, B. Allard, F. Costa, C. Vollaire, O. Picon, and L. Cirio, "An effcient dual-circularly polarized rectenna for RF energy harvesting in the 2.45 GHz ISM band," Progress In Electromagnetics Research, Vol. 148, 31-39, 2014.
14. Bao, X., K. Yang, O. O'Conchubhair, and M. J. Ammann, "Differentially-fed omnidirectional circularly polarized patch antenna for RF energy harvesting," 2016 10th European Conference on Antennas and Propagation (EuCAP), Davos, Switzerland, May 2016, doi: 10.1109/EuCAP.2016.7481820.
15. Cao, Y., W. Hong, L. Deng, S. Li, and L. Yin, "A 2.4 GHz circular polarization rectenna with harmonic suppression for microwave power transmission," Proceedings - 2016 IEEE International Conference on Internet of Things; IEEE Green Computing and Communications; IEEE Cyber, Physical, and Social Computing; IEEE Smart Data, iThings-GreenCom-CPSCom-Smart Data 2016, 359-363, May 2017, doi: 10.1109/iThings-GreenCom-CPSCom-SmartData.2016.85.
16. Huang, F. J., T. C. Yo, C. M. Lee, and C. H. Luo, "Design of circular polarization antenna with harmonic suppression for rectenna application," IEEE Antennas Wirel. Propag. Lett., Vol. 11, 592-595, 2012, doi: 10.1109/LAWP.2012.2201437.
17., "CST Studio Suite 3D EM simulation and analysis software,", https://www.3ds.com/products-services/simulia/products/cst-studio-suite/?utm_source=cst.com&utm medium=301&utm_campaign=cst (accessed May 2021).
18. Marqués, R., F. Mesa, J. Martel, and F. Medina, "Comparative analysis of edge- and broadside-coupled split ring resonators for metamaterial design - Theory and experiments," IEEE Trans. Antennas Propag., Vol. 51, No. 10, 2572-2581, Oct. 2003, doi: 10.1109/TAP.2003.817562.
19., "145-2013 - IEEE Standard for Definitions of Terms for Antennas/IEEE Standard/IEEE Xplore,", https://ieeexplore.ieee.org/document/6758443 (accessed Mar. 31, 2021).
20. Mabrouki, A., M. Latrach, and V. Lorrain, "High efficiency low power rectifier design using zero bias schottky diodes," 2014 IEEE Faible Tension Faible Consommation, Monaco, Monaco, 2014, doi: 10.1109/FTFC.2014.6828604.
21. Skyworks, "Surface mount mixer and detector schottky diodes data sheet, document #200041,", accessed: Mar. 31, 2021, [online], available: www.skyworksinc.com.