## 2 Wireless Communication Technologies
#### Smart Wearable Devices
The combination of 5G-wireless technology and machine-to-machine (M2M) communications enables the continuous monitoring of chronic diseases. Thus, M2M systems are seamlessly integrated with 5G-enabled devices to provide ongoing monitoring for chronic diseases. The design of an e-health system tailored for chronic patients was explored by studying the infrastructure and protocols of 5G networks [99]. Continuous data transfer and sensing applications were facilitated using 5G-cellular channels as highlighted [100]. The integration of IoT, machine learning, data analytics, and 5G and beyond-5G (B5G) networks have opened new ways for innovative diagnostic methods that have the potential to lower hospital and medical costs. Furthermore, 5G technology brings several advantages to robotic surgery care by providing faster download rates, video calls, and gaming capabilities [101]. Advancements in flexible and stretchable technology have also enabled the utilisation of implantable systems in various areas, including the deep brain, intravascular space, intracardiac space, and even the interior structure of a single cell [102]. Several new sensing devices have been designed; for example, a degradable, tuneable graphene-based antenna and a band stop filter/antenna sensor have been reported [103]. In [104], a 3D curved-shaped antenna was reported, featuring a curved layout and a non-radiating edge gap-coupled configuration, suitable for diverse applications. Furthermore, a lightweight and scalable flexible integrated circuit phased array system has been designed which can be conveniently stored or rolled in a limited space, as shown in Figure 3b [105]. In recent developments, a multi-material approach has emerged as a viable solution to enhance the safety of wireless, skin-based interfaced bioelectronic sensors. This approach, depicted in Figure 3c, utilises a combination of different materials to ensure improved safety and robust functionality of wearable and flexible devices [106]. Utilising biodegradable, implantable, and wearable sensors for healthcare could change the future of disease management in healthcare toward preventative, predictive, and personalised management of diseases. Furthermore, the manufacturing of biodegradable electronics and sensors that naturally dissolve under ambient conditions could mitigate electronic waste challenges. The degradation rates of materials and dissolution behaviour of bioresorbable devices in different biological systems can vary significantly. Furthermore, developing a high-performance and miniaturised power supply, circuits, and chips on biodegradable substrates and wireless transmission is required to develop a fully biodegradable platform. Among several options, biodegradable sensors (BD-SENs) have proven to be the best option and are widely used in the food and medical industries. Moreover, BD-SENs are widely used in implanted medical devices, which disintegrate into the body through various degradation mechanisms once the intended function is completed. The use of these implantable BD-SENs helps to avoid the need for additional sensor removal operations. Implantable sensors with controlled degradation mechanisms will also aid in determining how long the device should operate inside the body. The issue of electronic waste has been addressed by the design of these environmentally friendly and sustainable sensors, which also serve as a green substitute for traditional non-biodegradable sensors. Degradable piezoelectric biomaterials have recently attracted more attention as potential medicinal applications. They provide a self-sufficient solution using biomechanical energy harvesting. This promising path toward the development of cutting-edge, transient biomedical devices that support both improved patient care and real-time monitoring is made possible by the combination of degradable sensors with flexible, piezoelectric materials.