Back-to-Back Microstrip Antenna Design for Broadband Wide-Angle RF Energy Harvesting and Dedicated Wireless Power Transfer

Abstract

A novel back-to-back microstrip antenna is proposed to cover 2G/3G/4G/5G communication bands and ISM-2.4 GHz, ISM-5.8 GHz to simultaneously realize broadband wide-angle ambient wireless energy harvesting and dedicated wireless power transfer. The ground mode radiation is introduced by the limited-sized ground, with the loading of the patches and shorting vias, to form a broadband resonance from 2 GHz to 4 GHz. Furthermore, a resonance at ISM-5.8GHz is also excited with high-directivity. On the basis of ensuring miniaturization (e.g. 0.28 0  × 0.22 0  × 0.05 0  for 2 GHz) and compactness, omnidirectional radiation in broadband resonance and bi-directional radiation at 5.8 GHz are realized by the 'back-to-back' combination of two antenna elements. Measured results show that an over 67.2% impedance bandwidth (2.03 GHz~4.08 GHz) is obtained. Through the wireless power transmitting and receiving test, the angular stability of above ±60° for wireless energy harvesting is achieved at the mainstream operating frequencies. At ISM-2.4 GHz RF power of up to -8.5 dBm can be harvested at a distance of 0.5 m from the transmitter with the transmitting power of 12.5 dBm, while it is -8.9 dBm at ISM-5.8 GHz, which validates the effectiveness for WEH/WPT.

A Review of Circularly Polarized Dielectric Resonator Antennas: Recent Developments and Applications

“…Moreover, the proposed antenna should also have a high radiation efficiency and high gain to maximize the received RF power from the ambient RF sources. In previous works, numerous planar wideband antennas have been developed to collect RF energy from several frequency bands [81][82][83][84]. However, most of them are unable to obtain the satisfactory gain.…”

A Compact Broadband Stepped Bow-Tie Antenna for Ambient RF Energy Harvesting

“…In addition, recent studies have also conducted RFEH research on cellular bands and wireless local area network (WLAN) frequencies. To efficiently implement RFEH, several antennas have been implemented for wide bandwidth [6], [7], [8], [9], [10], multiple bands [11], [12], [13], wide beamwidth [14], [15], [16], [17], and high gain [18]. For applications such as IoT sensors, studies for compactness or flexibility have also been conducted [19], [20], [21].…”

“…To achieve wide bandwidth for the RFEH, most of the antennas consist of wide radiators [6], [7], [8], [9], [10], making surface current distributions correspond to each frequency. Reference [9] used the elliptical slot of the radiator to improve bandwidth, and [7] showed that the slot under the feedline can improve impedance matching.…”

“…Reference [9] used the elliptical slot of the radiator to improve bandwidth, and [7] showed that the slot under the feedline can improve impedance matching. Moreover, combining two antennas contributes to broadening the operating frequency [8], and diverse modes generated by the stacked structure make resonance frequencies [10]. Furthermore, using a stepped shaped antenna has proven to be a simple method to achieve wide bandwidth [25], [26], [27].…”