## 1 Introduction  
Energy harvesting for supplying power to low-power electronic devices has recently become mainstream research. The lifetime of a battery can be extended using a developed self-sustainable power supply. [PERSON] et al. designed a flexible wearable radiofrequency (RF) energy harvester for off-the-shelf two-way talk radios of 2 W using inkjet printing technology, and E- and H-field energy harvesters were verified using a light-emitting diode and microcontroller communication module [1]. [PERSON] et al. presents an integrated solution for a flexible direct current (DC)-DC converter by embedding a flexible polyimide printed circuit board and an inductor made of flexible ferrite-polymer composite in a wire [2]. A wearable RF-energy-harvesting device, which comprises a U-shaped dipole antenna, matching network, RF-DC converter, and DC-DC converter, was presented in [3] for supplying power to smart jewelry. This design converts a 915-MHz RF signal into a constant DC output voltage of 3.1 V at an input power of \(-6\) dBm, which is suitable for supplying power to a fitness monitor pendant under standby mode. An experimental comparison in [3] shows that the Dickson topology has high efficiency at a high input power. A commercial power supply or battery can be used as a stable power source for providing power to wireless sensor networks (WSNs). However, these power supplies have a finite lifetime, have a large size, incur high maintenance cost, and cause environmental pollution. RF energy harvesting was introduced because of potentially long lifespan, low-power consumption, and small size [4]. In this process, ambient energy is emitted from various sources, such as television (TV), radio, wireless Internet, satellite communication, and base stations, which is converted into feasible DC voltages. WSN devices powered by RF energy can be used in several applications, such as telemetry systems, RF tags, home automation, equipment monitoring, access control, and prolongation of lifespan of powered devices [5; 6]. In [7], a five-stage orthogonally switching charge pump rectifier with a voltage boosting network was used for an RF energy harvester. The rectifier provides a DC voltage and power conversion efficiency (_PCE_) of 1.3 V and 33.72%, respectively, with a load of 100 k\(\Omega\) from an RF source of \(-\)13 dBm at an ISM frequency. The WSNs are fabricated using low-power circuits, particularly by integrating with an antenna and a voltage multiplier for a stable power supply [8; 9]. A combination of a two-stage Villard multiplier with a three-stage Dickson voltage multiplier was proposed to increase output voltage and power efficiency [10]. A Villard-Dickson power harvester circuit can produce an output voltage of 4 V with an efficiency of 3.9% and an output voltage of 8.8 V with an efficiency of 14.6% without and with a matching circuit, respectively, at an input signal of 4.1 dBm from a TV station [10]. A microstrip matching circuit and zero-biased diode were used to improve the performance of the designed energy-harvesting device. The Internet of Things (IoT) is a well-known platform, wherein each physical object is connected to the Internet without requiring human interaction. Few people check for regular supply of power to IoT, excluding WSNs. To supply power to these communication devices for a long duration, a self-sustainable power system is required for complex networks [11]. A feasible technique is to harvest RF energy from external environmental sources, which could be used as an auxiliary power supply for increasing the battery life [12; 13]. In general, RF energy-harvesting bands from ISM (900-928 MHz) and WLAN (2.4/5 GHz) have received considerable attention because they can cover cities and countries due to their continuous emission as commercial bands [14; 15; 16]. In [17], RF energy harvesting employed a Wi-Fi band at a frequency of 2.4 GHz by using the P21 XXCSR-EVB evaluation board from Powercast.