A 0.8V, 152 μW, 433 MHz Mixer-First Receiver with a Self-Adjusted Frequency Tracking Loop

Chuan-Yi Wu,Yu-Te Liao,Yen-Ting Chen

doi:10.1109/access.2021.3092893

Abstract

This paper presents a 433 MHz low-power receiver utilizing an N-path filter technique and a self-frequency tracking mechanism. Without the front-end amplifier, the mixer-first architecture can reduce power consumption significantly. A self-adjusted frequency tracking loop (SA-FTL) adjusts local oscillator (LO) frequency to approach input RF frequency automatically, thereby enhancing conversion gain and lowering return loss. The receiver, implemented in a 0.18 μm CMOS process, achieves a sensitivity of -80 dBm at a bit error rate (BER) of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> and a data rate of 10 kb/s, while consuming 152 μW from a 0.8V voltage supply.

Highlights

Applications of wireless sensor networks (WSNs) are in widespread use in a variety of fields, such as environmental sensing, health care monitoring, and smart cities
The sensitivity of receivers is considered a key for avoiding excessive transmitter power requirements for long-distance data communication
If the frequency deviates from the desired frequency, which is determined by the frequency selector, the feedback digital-to-analog converter (DAC) controller continuously changes the varactor voltage and adjusts the frequency of the LC oscillator

Summary

Introduction

Applications of wireless sensor networks (WSNs) are in widespread use in a variety of fields, such as environmental sensing, health care monitoring, and smart cities. These sensor nodes are usually battery-powered and size-constrained. In [1]–[3], the schemes of direct envelope detection introduced sub-μW scale receivers without a mixer and oscillator in the architecture. The wide bandwidth and high noise figure cause reduced sensitivity of about −40 dBm. A super-heterodyne two-tone architecture was introduced in [4] to improve sensitivity, and a two-tone signal and envelope detector were used, creating a non-interfering intermediate frequency (IF) signal and reducing the in-band interference.

Methods

Conclusion