CMOS Radio Frequency Energy Harvester (RFEH) with Fully On-Chip Tunable Voltage-Booster for Wideband Sensitivity Enhancement

Abstract

Radio frequency energy harvesting (RFEH) is one form of renewable energy harvesting currently seeing widespread popularity because many wireless electronic devices can coordinate their communications via RFEH, especially in CMOS technology. For RFEH, the sensitivity of detecting low-power ambient RF signals is the utmost priority. The voltage boosting mechanisms at the input of the RFEH are typically applied to enhance its sensitivity. However, the bandwidth in which its sensitivity is maintained is very poor. This work implements a tunable voltage boosting (TVB) mechanism fully on-chip in a 3-stage cross-coupled differential drive rectifier (CCDD). The TVB is designed with an interleaved transformer architecture where the primary winding is implemented to the rectifier, while the secondary winding is connected to a MOSFET switch that tunes the inductance of the network. The TVB enables the sensitivity of the rectifier to be maintained at 1V DC output voltage with a minimum deviation of −2 dBm across a wide bandwidth of 3 to 6 GHz of 5G New Radio frequency (5GNR) bands. A DC output voltage of 1 V and a peak PCE of 83% at 3 GHz for −23 dBm input power are achieved. A PCE of more than 50% can be maintained at the sensitivity point of 1 V with the aid of TVB. The proposed CCDD-TVB mechanism enables the CMOS RFEH to be operated for wideband applications with optimum sensitivity, DC output voltage, and efficiency.

Recent Development of High-PCE CMOS RF-DC Rectifier With Wide PIN Dynamic Range: Strategies and Trends—Review

“…Figure 8(d) shows that the double-sided bias by [57] also generates a positive bias for M4 for improved sensitivity. A similar bias by [61]- [65] also reported an enhanced sensitivity performance. This bias voltage on M4 is adversely delays turning off M4, leading to an undesirable discharge of C2 and diminishing the effect of voltage doubling during φ2.…”

Reconfigurable Antennas for RF Energy Harvesting Application: Current Trends, Challenges, and Solutions from Design Perspective

“…The advanced feature of these reconfigurable antennas is the maximization of wireless communication through the integration of many radios onto a single platform. Due to their ability to operate over a broad frequency range, modify their geometries, and adapt to changes, reconfigurable antennas are therefore being viewed as a practical solution to cover the variety of wireless services [74][75][76][77]. There are several reconfiguration properties: frequency reconfigurability [78][79][80][81], polarization reconfigurability [82][83][84][85], pattern reconfigurability [86][87][88][89], hybrid reconfigurability [90][91][92][93], electrical diversity [94][95][96][97], optical diversity [98][99][100][101], mechanical diversity [102][103][104][105], material diversity [106][107][108][109], etc.…”