Ultra-low power transceiver for no-battery applications

Abstract

This thesis presents system and circuit design techniques for an Ultra low Power Transmitter (Sub 1mW) to be used in Internet of Things (IoT) and Wireless Sensor Network (WSN) Applications. The implementation is driven by the continuous need for decreasing the energy consumption of wireless transceivers for the WSN and IoT applications, Wireless Sensor networks is seeking continuous reduction in power consumption, since frequent battery change is impractical. This transceiver aims to utilize multiple phases from a ring oscillator to generate higher frequency component at transmitter and receiver side, enabling oscillator design at much lower frequency than carrier frequency, edge-combiner-type power amplifier to operate the oscillator at only 1/3 of the RF frequency. A non-PLL based local oscillator architecture have a fast startup and calibration time to enable further energy saving. The close in phase noise is mitigated by using a largely separated tones for 1’s and 0’s, treading off the spectral efficiency with the ultra low power consumption. This enables installation of this transceiver on energy harvesting system without using any conventional power source. The transmitter was implemented on standard CMOS 0:18m process (IBM7RF), occupying an active area of 0.112 mm2. Targeting the ISM band from 902 MHz to 928MHz. The transmitter was tested on a test board using external matching network achieving power consumption lower than 1mW at -10dBm output power.

Keywords : Low Power, Ultra-low Power, Transmitter, PLL-less, Battery-less, Transceiver, Matching Network, PCB, WSN, Ring Oscillator, Edge Combiner, ISM, Radio Frequency, RF, Power Amplifier