Citation: Ketata, I.; Ouerghemmi, S.; Fakhfakh, A.; Derbel, F. Design and Implementation of Low Noise Amplifier Operating at 868 MHz for Duty Cycled Wake-Up Receiver Front-End. Electronics 2022, 11, 3235. https://doi.org/10.3390/electronics 11193235 Academic Editor: Dimitris Kanellopoulos Received: 13 September 2022 Accepted: 3 October 2022 Published: 8 October 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). electronics Article Design and Implementation of Low Noise Amplifier Operating at 868 MHz for Duty Cycled Wake-Up Receiver Front-End Ilef Ketata 1,2, * , Sarah Ouerghemmi 1,2 , Ahmed Fakhfakh 2 and Faouzi Derbel 1 1 Smart Diagnostic and Online Monitoring, Leipzig University of Applied Sciences, Wächterstraße 13, 04107 Leipzig, Germany 2 Laboratory of Signals, Systems, Artificial Intelligence and Networks (SM@RTS), National School of Electronics and Telecommunicationsof Sfax, Technopole of Sfax, 3018 Sfax, Tunisia * Correspondence: ilef.ketata@htwk-leipzig.de Abstract: The integration of wireless communication, e.g., in real- or quasi-real-time applications, is related to many challenges such as energy consumption, communication range, quality of service, and reliability. The improvement of wireless sensor networks (WSN) performance starts by enhancing the capabilities of each sensor node. To minimize latencies without increasing energy consumption, wake-up receiver (WuRx) nodes have been introduced in recent works since they can be always-on or power-gated with short latencies by a power consumption in the range of some microwatts. Compared to standard receiver technologies, they are usually characterized by drawbacks in terms of sensitivity. To overcome the limitation of the sensitivity of WuRxs, a design of a low noise amplifier (LNA) with several design specifications is required. The challenging task of the LNA design is to provide equitable trade-off performances such as gain, power consumption, the noise figure, stability, linearity, and impedance matching. The design of fast settling LNA for a duty-cycled WuRx front-end operating at a 868 MHz frequency band is investigated in this work. The paper details the trade-offs between design challenges and illustrates practical considerations for the simulation and implementation of a radio frequency (RF) circuit. The implemented LNA competes with many commercialized designs where it reaches single-stage 12 dB gain at a 1.8 V voltage supply and consumes only a 1.6 mA current. The obtained results could be made tunable by working with off-the-shelf components for different wake-up based application exigencies. Keywords: wireless sensor networks; wake-up receiver; duty cycled; low noise amplifier; sensitivity; power consumption; radio frequency; hardware challenges; performances analyses 1. Introduction With recent technological advancements, the internet of things (IoT) is nowadays at the cutting edge of transforming various fields to a level of smartness by storing and processing data in a distributed manner to enhance productivity. Internet of things (IoT) technology is based on powerful wireless devices intercon- nected in a complex ecosystem that enables one to gather, share, and analyze information and take actions appropriately [1]. These wireless devices are called sensor nodes, dis- persed through different technologies and communicating at different frequency levels in a wide network.A number of applications such as weather [2], health, military, transport, localization [3,4], and smart automotive depend on the potential of sensor nodes to over- come the challenges of wireless sensor nodes [5]. In contrast, the specific requirements and performances for sensor nodes obviously depend on the application they will serve [6], the effect to be sensed, the amount of the data rate transferred [7], and subsequently on the power consumed [8]. Data rate, transmission power, and power consumption in the sensor node are also related to the operating frequency. Some RF bands, such as 2.4 and 5 GHz, are highly populated bands that enable con- nectivity and coverage but face much interference from the extensive demand of other Electronics 2022, 11, 3235. https://doi.org/10.3390/electronics11193235 https://www.mdpi.com/journal/electronics