**1. Introduction**

Electronic gadgets and tools that are used to communicate device-to-device and deviceto-human through wireless communication are termed wireless devices. Radio waves and infrared signals are some of the widely preferred wireless communication methods due to their reliability and flexible installation. Wireless communication technologies are categorized based on their signal strength and communication distance. Smartphones, laptops, smartwatches, Wi-Fi routers, Bluetooth speakers, and wireless headphones are some of the familiar wireless devices used in day-to-day life. The wireless connectivity in such devices is established through internal or external adapters and receivers. Therefore, wireless devices have the ability to move around anywhere in the network area; furthermore, the constraints of physical cables and wires are eliminated. In recent years, wireless communication devices have been incorporated into various sectors for improving their mobility and

**Citation:** Hezekiah, J.D.K.; Ramya, K.C.; Radhakrishnan, S.B.K.; Kumarasamy, V.M.; Devendran, M.; Ramalingam, A.; Maheswar, R. Review of Next-Generation Wireless Devices with Self-Energy Harvesting for Sustainability Improvement. *Energies* **2023**, *16*, 5174. https:// doi.org/10.3390/en16135174

Academic Editor: Chunhua Liu

Received: 6 June 2023 Revised: 27 June 2023 Accepted: 3 July 2023 Published: 5 July 2023

**Copyright:** © 2023 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/).

productivity [1–5]. Figure 1 shows sectors that have been widely updated with wireless communication in recent days.

**Figure 1.** Wireless devices in various sectors.
