Multi-standard transceiver solutions for IoT applications

Abstract

This work aims to develop multi-standard wireless transceiver solutions for multi-rate IoT applications. Chapter 1 deals with the development of a transmitter (TX) employing a harmonic rejection phase interpolator-based, open-loop BFSK modulator with an enhanced sidelobe suppressed switch-capacitor, a class-D power amplifier for long-range IoT applications in the $902–915 MHz$ band. To overcome the well-known data rate limitation problem in PLL-based closed-loop BFSK modulators, the proposed modulator operates in an open-loop fashion, whereby it continuously provides the two BFSK tones by successively interpolating and switching between the available input phases. High-resolution (7-bit) phase interpolation is achieved to reduce the modulated carrier’s phase noise, while additional 2-bit effective phase resolution is achieved by randomizing the phase transition time. Hence, a 9-bit effective phase interpolation results in a better carrier phase noise profile in addition to the reduced level of oversampling clock’s spur. The baseband TX data is applied to the TX portion, where switching between the two BFSK tones is linear (proposed BFSK) rather than abrupt (conventional BFSK), resulting in lower power in the adjacent channels. The application of baseband data to the TX rather than the modulator helps in achieving high data rate FSK modulation with lower adjacent channel power (ACP). Chapter 2 presents an inductor-less, low-power, wideband, and noise-cancelling low-noise amplifier (LNA). The main novelty of this LNA lies in the concurrent utilization of feedforward and feedback techniques to achieve simultaneous noise and distortion cancellation of the input stage along with bandwidth extension while maintaining low-power input matching, respectively, thereby making this LNA a suitable contender for simultaneous deployment in low-power and multi-standard IoT applications.