A 0.42-mW 1-Mb/s 3- to 4-GHz Transceiver in 0.18- $\mu \text{m}$ CMOS With Flexible Efficiency, Bandwidth, and Distance Control for IoT Applications

This paper describes a short-range transceiver architecture using frequency-hopped sinusoidal OOK pulses. Since signal bandwidth does not necessarily have to satisfy >500 MHz requirement like conventional ultra-wideband (UWB) pulses, the proposed transceiver named as a very-wide band (VWB) transceiver offers degrees of freedom to choose an optimum operation duty cycle in terms of energy efficiency, bandwidth efficiency, and communication range, while providing much lower operation duty cycle than that of narrow band OOK transceiver. The VWB transmission significantly relaxes the complexity of transceiver design without requiring advanced CMOS technology. In the transmitter, pulse generation circuit design is simplified with the duty-cycled sinusoidal signal compared to that in the impulse-radio UWB (IR-UWB) transmitter. In the receiver, an asynchronous energy detection topology is proposed to achieve robust energy detection by overcoming the synchronization issue as well as the saturation problem of the integrator circuit. A prototype 3-to-4 GHz VWB transceiver is implemented in 0.18 $\mu \text{m}$ CMOS. The transceiver achieves the communication distance of >2 m at 1 Mb/s data rate with the peak-to-peak pulse amplitude of only 300 mV and the duty cycle of 0.6%, consuming 0.42 mW from a 1.8 V supply.