Ultra-low Power Ultra-wideband Research Articles

An Energy-Efficient UWB Transmitter with Wireless Injection Locking for RF Energy-Harvesting Sensors.

An ultralow-power ultrawideband (UWB) transmitter with an energy-efficient injection-locked radio frequency (RF) clock harvester that generates a carrier from an RF signal is proposed for RF energy-harvesting Internet-of-Things (IoT) sensor applications. The energy-efficient RF clock harvester based on the injection-locked ring oscillator (ILRO) is proposed to achieve optimal locking range and minimum input sensitivity to obtain an injection-locked 450 MHz clock in ultralow-power operation. A current-starved inverter-based delay stage is adopted that allows delay adjustment by bias voltage to minimize dynamic current consumption while maintaining a constant delay regardless of changes in process, supply voltage, and temperature (PVT). To minimize static current consumption, a UWB transmitter based on a digital-based UWB pulse generator and a pulse-driven switching drive amplifier is proposed. The proposed injection-locked RF clock harvester achieves the best RF input sensitivity of −34 dBm at a power consumption of 2.03 μW, enabling energy-efficient clock harvesting from low RF input power. In ultralow-power operation, a 23.8% locking range is achieved at the RF injection power of −15 dBm to cope with frequency changes due to PVT variations. The proposed UWB transmitter with RF clock harvester achieves the lowest energy consumption per pulse with an average power consumption of 97.03 μW and an energy consumption of 19.41 pJ/pulse, enabling operation with the energy available in RF energy-harvesting applications.

High efficiency UWB pulse generator for ultra-low-power applications

This paper presents the design of a fully integrated ultra-low-power Ultra Wide Band (UWB) pulse generator. The circuit is designed and optimized for low rate and localization applications. This UWB transmitter is based on the impulse response filter method in order to achieve high energy sub-nanosecond pulses. The circuit has been integrated in a ST-Microelectronics CMOS 0.13 μm technology with a supply voltage of 1.2 V on a die area of 0.56 mm2. A power manager is used to reduce the power leakages to 3.91 μW which gives a power consumption of 3.98 Mw at 10 kb/s. The measured dynamic energy consumed per pulse is 68 pJ and the measured energy of the emitted pulse is 2.15 pJ.

An Ultralow-Power Dual-Band UWB Impulse Radio

In this brief, we present a dual-band ultralow-power ultrawideband (UWB) impulse radio (UWB-IR) transceiver in a 90-nm CMOS process for low-data-rate UWB on-off keying (OOK) communications. The dual-band topology enables separation of timing and data impulses for simplified synchronization and duty cycling. The receiver can dynamically switch between two 500-MHz bands centered at 3.5 and 4.5 GHz with an interband isolation of 30 dB. With a fast turn-on time of ~1-2 ns, the total power requirement of the duty-cycled receiver (Rx) block is measured to be 12 μW at 100 kb/s for a Rx sensitivity of -87 dBm and a bit error rate (BER) of 10-3. The dual-band impulse-based transmitter (Tx) is designed using a duty-cycled LC oscillator topology enabled only when a transmission is requested and consumes only 8 μW at 100 kpulse/s. For a BER of 10-3 , the instantaneous signal-to-interference ratio was measured to be better than -50 dB for a 2.4-GHz narrowband interferer. The total power for the transceiver at 20 μW is an order of magnitude better than state-of-the-art designs for comparable performance.