2.4-GHz 16-QAM Passive Backscatter Transmitter for Wireless Self-Power Chips in IoT

A 2.4-GHz 16-QAM ultra-low-power passive transmitter for wireless self-power chips in IoT is proposed. To expand wireless sensor networks, it achieves energy harvest and low-power wireless communication with 2.4-GHz infrastructure. Besides, the backscatter technique is employed to reduce power consumption and is compatible with multiple quadrature amplitude modulation (M-QAM) to increase data rate. Measured results show that the transmitter just dissipates 1 μW from 1.8-V supply voltage with 6.46% EVM at 4-Mb/s data rate. Moreover, the transmitter has great availability whether at 100 Mb/s data rate or for the input power of a wide dynamic range. The chip is fabricated in the 0.18-μm 1P6M standard CMOS process and occupies a silicon area of 1465 × 915 μm2 without pads.