In this paper, the evolution and milestones of RFEH and related breakthroughs over the years are reviewed and presented. The review begins with an overview of the surging energy crisis due to the increasing demand for wireless communication devices. Furthermore, the RFEH mechanism that discusses the frequency bands utilized, the near field, and the far-field propagation are also presented. Various rectification techniques in CMOS RFEH, from the fundamental rectification method to cross-coupled-differential-drive (CCDD), are also examined and discussed. The performance is gauged through harvested output DC voltage and the power conversion efficiency (PCE) as well as the RF input power sensitivity. An assessment on the non-CMOS RFEH that includes the Schottky diode and Rectenna is also concisely described to analyze their contribution to RFEH’s performances enhancement. Finally, a particular highlight of the 5G RFEH in mmWave is provided in presenting this work as an ongoing future solution to reduce the electronic circuit’s battery dependency. The pros and cons of all the presented RFEHs are summarized and discussed as well. Continuous research and development activities are extensively being executed in developing a system that could ultimately solve the world’s energy crisis, and RFEH seems to be a revolutionary approach.

A low-power capacitorless demultiplexer-based multi-voltage domain low-dropout regulator (MVD-LDO) with 180 nm CMOS technology is proposed in this work. The MVD-LDO has a 1.5 V supply voltage headroom and regulates an output from four voltage domains ranging from 0.8 V to 1.4 V, with a high current efficiency of 99.98% with quiescent current of 53 µA with the aid of an integrated low-power demultiplexer controller which consumes only 68.85 pW. The fabricated chip has an area of 0.149 mm² and can deliver up to 400 mA of current. The MVD-LDO’s line and load regulations are 1.85 mV/V and 0.0003 mV/mA for the low-output voltage domain and 3.53 mV/V and 0.079 mV/mA for the high-output voltage domain. The LDO consumes only 174.5 µW in standby mode, making it suitable for integrating with an RF energy harvester chip to power sensor nodes.