Radio Frequency Energy Harvesting IC for ISM-915 MHz and 2.45 GHz Wireless Transmitter

This paper proposes a dual-band radio-frequency energy harvesting (RFEH) chip Institute of Supply Management (ISM)-915 MHz and ISM-2.45 GHz wireless transmitter. It is composed of the matching network, multiplier and rectifier, over-voltage protection circuit, and low power low-dropout (LDO) voltage regulator. In the input matching network, the destination is not only to obtain the maximum power transfer but also to have the maximum conversion efficiency. In the rectifier circuit, the dynamic threshold-voltage MOSFET (native MOS) is used to complete the Dickson voltage multiplier circuit which converts the RF signal into dc voltage with boosting function. Next, an over-voltage protection circuit is considered to prevent the front-end RF circuit from damaging by high output voltage at near-field region. Finally, a low power LDO is used to produce a stable output voltage, which is used to charge the battery stably. The proposed RFEH IC is designed and implemented with standard TSMC 0.18-$\mu$m 1P6M CMOS process. According to the simulated results, the maximum conversion efficiencies of rectifier and entire system are 30.5% and 24.945% with an input powers of 0 dBm and 2 dBm, respectively, at the radio frequency of 915 MHz. Besides, the maximum conversion efficiency of rectifier and entire system are 30.3% and 24.404% with an input power of 2 dBm and 1 dBm, respectively, at the radio frequency of 2.45 GHz. As the input powers are fed from 5 dBm to 20 dBm, the output currents vary from 0.2 to 0.3 mA and the power consumptions alter from 0.3071 to 0.4355 mW, respectively. Notify that a stable output voltage is approximately 1.47 V. The chip area is about 0.867 $\times$ 0.967 mm
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