RESEARCH ARTICLE A dual-band high-gain quasi-Yagi antenna with split-ring resonators for radio frequency energy harvesting Zhicong Chen 1 | Miaowang Zeng 2 | Andrey S. Andrenko 3 | Yongzhao Xu 2 | Hong-Zhou Tan 1,4 1 School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, China 2 DGUT-CNAM Institute, Dongguan University of Technology, Dongguan, China 3 EMC Laboratory, National Institute of Information and Communications Technology, Tokyo, Japan 4 SYSU-CMU Shunde International Joint Research Institute, Shunde, China Correspondence Miaowang Zeng, DGUT-CNAM Institute, Dongguan University of Technology, Dongguan, China. Email: zengmw@dgut.edu.cn Funding information Dongguan Science and Technology Project, Grant/Award Numbers: 2014215130, 2014509130207, 2015108101006; Research Start-up Funds of DGUT, Grant/Award Number: GC300501-097 Abstract This article presents a quasi-Yagi antenna operating with high gain at two frequency bands. Compared with a con- ventional Yagi antenna, the proposed antenna is designed by integrating a pair of printed split-ring resonators (SRRs) into the antenna layout. The SRRs introduce a new reso- nant frequency band and the antenna gain remains high at both the bands. The simulated and measured results show that the antenna is well matched while the antenna gain is 6 and 5.80 dBi at the GSM1800 and ISM2450 bands, respectively. The proposed antenna is compact and effi- cient and achieves high gain so that it could be successfully used in various wireless communication and radio fre- quency energy harvesting applications. KEYWORDS dual-band, high gain, quasi-Yagi antenna, RF energy harvesting, split- ring resonators (SRRs) 1 | INTRODUCTION Recently, the quasi-Yagi antennas have drawn much attention due to their good performance, such as end-fire radiation pat- tern, high gain, low cost, and easy integration with radio fre- quency (RF) circuitry. A quasi-Yagi antenna usually consists of a feed, a driven element, a reflector, and one or more direc- tors. There are several typical feeding methods, including microstrip lines, 1 coplanar waveguides (CPWs), 2 coplanar striplines, 3 and microstrip-slotline transition. 4 The main radiat- ing element is designed using a dipole or a folded dipole to obtain a wider bandwidth. The directors are integrated as pas- sive radiators which have no transmission line connection. The currents on parasitic elements are induced by the EM fields from the driven element. The directors serve in such a manner so as to affect the phase of the radio waves, concentrating energy in one particular direction. Quasi-Yagi antennas are widely used in the wireless RF applications, such as phase arrays, 5 wireless communication, 6 and power combining. 7 In the aspects of theory, it is well known that the high- gain characteristics of quasi-Yagi antennas can be achieved by proper amplitude and phase condition between the driven element, reflector, and directors. 8 However, the frequency range with high gain, namely bandwidth of a Yagi antenna is relatively narrow, typically only a few percent of the center frequency. Thus, a high-gain performance can be achieved only in the narrow band. To enhance the bandwidth of printed quasi-Yagi antenna, a compact planar quasi-Yagi antenna with size reduction is reported in Reference 9 where the anten- na’s bandwidth widens to 8 GHz but only a bit better than 4 dBi of measured gain is obtained. In Reference 10, a planar quasi-Yagi antenna with dual-band performance is proposed, but the gain is relatively low over the operating bands. A quasi-Yagi antenna with two frequency-dependent radiation patterns is reported in Reference 11. Opposite radiation pat- terns at the two bands are obtained by using split-ring resona- tors (SRRs). Reference 12 proposes a compact and wideband quasi-Yagi antenna, but the gain of the antenna just varies between 3 and 5.5 dBi. Many dual-band or broadband quasi- Yagi antennas have been proposed in recent years, but very few works report a high gain at both the frequency bands. In this article, a dual-band quasi-Yagi antenna with high gain at the dual design bands is presented. By combining the SRRs with quasi-Yagi antenna structure, a new resonant fre- quency with high-gain property is obtained as compared with a conventional quasi-Yagi antenna. The proposed antenna operates at the DCS1800 and ISM2450 bands and achieves a gain larger than 5 dBi over the design bands. Received: 16 January 2019 DOI: 10.1002/mop.31872 Microw Opt Technol Lett. 2019;1–8. wileyonlinelibrary.com/journal/mop © 2019 Wiley Periodicals, Inc. 1