RADIOENGINEERING, VOL. 27, NO. 3, SEPTEMBER 2018 711 DOI: 10.13164/re.2018.0711 ELECTROMAGNETICS A Novel Split-Ring Resonator and Voltage Multiplier Based Rectenna Design for 900 MHz Energy Harvesting Applications Merih PALANDOKEN, Cem GOCEN, Adnan KAYA, Fethullah GUNES, Cem BAYTORE, Fatih Cemal CAN Electrical and Electronic Engineering Dept., Izmir Katip Celebi University, Izmir, Turkey merih.palandoken@ikc.edu.tr, gocencem@gmail.com, {adnan.kaya, fethullah.gunes, cem.baytore, fatihcemal.can}@ikc.edu.tr Submitted March 26, 2018 / Accepted June 14, 2018 Abstract. This paper proposes a novel rectenna design for the compact RF energy harvesting system operating at 900 MHz. The rectenna design is based on a probe fed split-ring resonator on an elliptical slotted ground plane and an RF-DC rectifying circuit in the form of Villard voltage doubler circuit. The energy harvesting antenna is numerically modeled and fabricated on a 1.524 mm thick Rogers RO4003C substrate with a compact overall size of 81.25 mm  87.5 mm (λ 0 /4.1  λ 0 /3.8). The measured re- flection coefficient indicates the proposed energy harvest- ing antenna to operate at 890 MHz with 51.3 MHz band- width covering GSM 900 band. As an RF-DC rectifying electronic circuit, a one stage voltage doubler circuit based on zero bias Schottky barrier diode in conjunction with the inductive impedance matching and λ/4 impedance transformer circuits has been designed. The DC voltage of nonlinear RF rectifier circuit is obtained as 1.7 V at the output load for –11 dBm input power level. The measured and simulated results confirm the proposed rectenna sys- tem to have a technical potential for the operation of low power and low voltage electronic devices. Keywords RF energy harvesting, rectenna, microstrip antenna, RF-DC conversion, voltage multiplier 1. Introduction In recent years, there has been a rapid growth in many wireless communication applications such as wireless sen- sor networks and IoT [1]. Since these wireless applications consist of a large number of low power, low voltage oper- ating sensors, ubiquitous and continuous supply of energy is essential for their reliable operation [2]. As the power demand increases, the need for the alternative energy sources has become important. In this regard, energy har- vesting from the ambient environmental energy sources and corresponding power conversion to the usable DC voltage levels is the key solution [3]. With the technologi- cal and scientific improvements, RF energy harvesting technique becomes more efficient. In the modern environ- ment, there are multiple external ambient RF energy sources at different operating frequencies radiating RF power in all directions. These sources are TV and radio broadcast stations, mobile phone base stations, cellular phones, and wireless Local Area Network (LAN) trans- ceivers. RF energy harvesting system targets the continu- ous gathering of RF energy from the external ambient sources for the purpose of providing sufficient DC power to the low power electronic equipment. In RF energy harvesting technique, the radio signals with the frequency range from 300 GHz to as low as 3 kHz are used as the RF input source to be rectified into the permissible DC voltage level [2]. Therefore, the diverse frequency spectrum opportunity for the RF energy har- vesting is existing to energize the low power devices with- out the regular need of replacing batteries [4]. In addition, there is an active research potential in the investigation of the multiple alternative ways to scavenge energy from the environment and convert into the DC electrical energy to energize the low power devices [5]. The basic RF energy harvesting system block diagram is shown in Fig. 1. RF energy harvesting system includes the receiving antenna, matching network and rectifying circuit. The environmentally freely available RF energy is conveniently captured by the receiving antenna and con- verted into the permissible DC power level by the voltage rectifier circuitry. In this system, the receiving antenna is utilized for gathering RF signals from the environment in every location in space. Antenna physical dimensions, high directive gain, and good radiation pattern are the main aims of the antenna design. Another important part of the system is the matching network. The crucial task of matching network is to reduce the reflection and transmission losses from the receiving antenna to the RF rectifier electronic circuit and increase the output voltage of the rectifier circuit