Low-power multi-band injection-locked wireless receiver

Abstract

The demand for low-power high-performance wireless receivers has dramatically in- creased with the emerging deployment of wireless sensor networks (WSNs). Among the demodulation schemes, non-coherent receivers consume less power in comparison with its counterpart, e.g. the coherent receiver, attributed to its simple architecture and fewer com- ponents. The injection-locking based envelope detection design, consisting of a low-noise amplifier (LNA), injection-locked oscillator, and an envelope detector, has drawn a lot more attention in recent years for low-power non-coherent demodulation. However, the utilization of the injection-locked oscillator, providing flexibility and high performance, remains quite challenging. This thesis describes both the circuit level and mathematical model of injection- locking, allowing for the implementation of a CMOS receiver offering low-power, high per- formance and the ability to support multiple radio frequency bands. By leveraging both fundamental and superharmonic injection-locking, the receiver is capable of operating at ve frequency bands, e.g., 433 MHz, 863 MHz, 915 MHz, 950 MHz, and 2.4 GHz, used for WSN applications. One of the challenges of making use of superharmonic injection-locking is the narrow lock range that is insufficient for the oscillator to implement frequency-to-amplitude conver- sion under the locked-in status while maintaining low-power performance. A mathematical model developed in this work reveals the relationship between the lock range of superhar- monic injection-locking and the third-order coefficient of the nonlinearity. An examination of the injection transistor operating in the weak and strong inversion region leads to the discovery of an optimal biasing point in the subthreshold region where the maximum lock range can be attained.