Energy harvesting technology is to convert the energy of the surrounding envi-ronment, which exists in various types, into useful energy through various methods. Typical energy sources in the surrounding environment include light, vibration, heat, and RF/Microwave signals, and these energies are collected in various ways. Most of the collected energy is converted into electrical energy that is convenient for con-version, and as interest in the environment increases in recent years, research in the relevant field is being actively conducted.
Energy harvesting technology in the field of RF/Microwave uses a method of col-lecting energy by converting electromagnetic energy induced in a wire into DC power. This is attracting attention due to the increase in detectable signals and the rapid development of related devices as wireless communication devices and Internet of Things (IoT) devices are disseminated due to the recent 4th industrial revolution. In addition, the low power consumption of various electronic devices means that the low energy supply rate, which was the biggest problem in this field, is no longer a prob-lem, and this trend means that the RF energy harvesting system can be used as a power source for low power systems such as IoT devices, etc.
In this paper, we propose a dual polarization RF energy harvesting system operat-ing in the 2.45 GHz industrial, scientific and medical (ISM) band, which is a repre-sentative unlicensed band mainly used by IoT devices. The proposed energy har-vesting system has characteristics independent of incident polarization by applying a dual linear polarization antenna composed of two bowtie-type meander dipole anten-nas. For miniaturization, the LC balun, impedance matching circuit, and Dickson charge pump rectifier circuit are placed at the center of the system to propose a structure in which all functions are integrated into one two-layer PCB board.
In addition, a two-stage Dickson charge pump circuit with optimal efficiency was selected by considering the efficiency of each diode stage of the Dickson charge pump rectifier circuit. The structure in which the outputs of the two rectifier circuits are connected in parallel has about 1.8 times more conversion power than a single polarization energy harvesting system, and has a maximum RF-DC conversion effi-ciency of 71.4 %. Therefore, the proposed energy harvesting system can act as a power source for various ultra-low power consumption systems such as IoT applica-tions and medical applications due to its small size and improved harvesting power at various incident polarization angles.