Dilip Kumar Choudhary, PhD is an assistant professor in the School of Electronics Engineering at the Vellore Institute of Technology. He has authored over 35 articles in international journals and conferences, one copyright, and two book chapters. His research interests include microwave filtering circuits, metamaterials, antennas, power dividers, and couplers for wireless communication.Indrasen Singh, PhD is an assistant professor in the School of Electronics Engineering at the Vellore Institute of Technology with over 15 years of teaching and research experience. He has published over 20 research papers in national and international journals and conferences of repute and serves as an editor for several journals. His research interests include cooperative communication, stochastic geometry, modeling of wireless networks, heterogeneous networks, millimeter wave communications, device-to-device communication, and 5G and 6G communication.Manoj Kumar Singh is a senior project manager at Ericsson Global India Service Pvt. Ltd. in Noida, Uttar Pradesh, India with over 16 years of professional experience. He has many notable industry certifications, including PMP and CSM, Enterprise Design Thinking from IBM, cloud computing, and GenAI project management. His experience has driven global project transformations and advancements in telecoms technology. His research interests include automation development using Python, Java, and AI and machine learning.Amit Kumar Jain, PhD is a lecturer in the Department of Mechanical Engineering in the School of Computing, Engineering, and Built Environment at Glasgow Caledonian University. He has published two books and over 20 papers in reputed academic journals and conferences in addition to serving as an industry consultant and reviewer for several international journals. His research interests include reliability, Industry 4.0, manufacturing analytics, and operations management.

• Preface xiii1 A Systematic Survey on Wearable Biomedical Sensors Using Flexible Microwaves Devices 1Warisha Fatima, Shailendra Kumar, Mohd Javed Khan and Indrasen Singh1.1 Introduction 21.2 Literature Survey 31.3 Procedure and Working 111.4 Next-Generation Wearables: A Strategic Plan for the Future 141.5 Conclusion 172 Metamaterials in 5G and the Path towards 6G: Enabling Advanced Wireless Communication 25Mohd Javed Khan, Saif Ahmad, Indrasen Singh and Zeenat Fatima2.1 Introduction 262.2 Basics of Metamaterials 282.3 Metamaterials in 5G Communication 342.4 Towards 6G: Future Challenges and Metamaterials Integration 382.5 Case Studies and Applications 402.6 Future Directions and Research Challenges 432.7 Conclusion 443 Optimization of Time-Modulated Circular Antenna Array for MIMO Systems through Evolutionary Algorithms 49Satish Kumar, Gopi Ram, Durbadal Mandal and Rajib Kar3.1 Introduction 503.2 Design Equations 513.3 Evolutionary Optimization Method Used 553.4 Cost Function Formulation 553.5 Computational Result 563.6 The Convergence Curves of DE, PSO, and NPSO 613.7 Conclusions 624 Fractal Antenna MIMO Arrays: A Promising Multiband Solution for Modern 5G Wireless Automotive Applications 65Gurmeet Singh, Ashish Kumar and Amar Partap Singh Pharwaha4.1 Introduction 664.2 Various Forms of Antenna Array 694.3 Feed Networks for Antenna Array 754.4 Fractal Geometries 764.5 Fractal Antenna Arrays 824.6 Recent Trends in the Fractal Antenna Arrays 894.7 Conclusion 935 Multiband Fractal Antenna: A Novel Miniaturization Technique 97Ruchi Kadwane5.1 Introduction 985.2 Fractal Designs 985.3 Iterative Function System 1035.4 Advantages and Limitations of Fractal Geometry in Antennas 1045.5 Compact Printed Multiband Fractal Antenna: Novel Design Approach 1055.6 Conclusion 1216 Applications of Metasurfaces for Modern Planar Antenna Design 125V. Bharathi, Parthasarathy Ramanujam and Krishnamurthy Ramanujam6.1 Metasurfaces -- Introduction and Characteristics Relationship 1266.2 Characteristics Mode Analysis (CMA) 1306.3 Realization and Evaluations of MS-Based Antenna Models 1376.4 Frequency Selective Surfaces and Its Types 1396.5 Relationship Between Mutual Coupling Reduction and FSS Superstrate in CP-MIMO Antennas 1446.6 Conclusion 1467 A Review on Electromagnetic Metamaterial Absorbers and Its Application 151Surender Singh Bisht, Amit Kumar and Dharmendra K. Jhariya7.1 Introduction 1527.2 Types of Electromagnetic Metamaterial Wave Absorbers 1567.3 Type of Metamaterial 1587.4 The Metamaterial (MTM) Absorbers Theory 1627.5 Different Approaches for Analysis of Microwave Absorption 1657.6 Narrowband Metamaterial Absorbers 1677.7 Electromagnetic Metamaterial Design Consideration 1697.8 Applications of Electromagnetic Metamaterial Absorbers Are Classified on Frequency Range 1727.9 Applications and Research Area of Electromagnetic Metamaterial Absorber 1747.10 Advancements in Metamaterials in Recent Times 1867.11 Conclusion and Prospects for the Future 1878 RF-Based Wearable PPG Sensor for Real-Time Cardiovascular Health Monitoring 197Mohammed Arshad Ali Khan and Geetha Chakaravarthi8.1 Introduction 1988.2 Motivation 1998.3 The Fundamental of Photoplethysmography 2018.4 RF-Based Wearable Sensors and Applications in Healthcare Monitoring 2058.5 Methodology 2098.6 Experimental Setup of EH Module Integrated with PPG Sensor 2138.7 Data Analysis 2148.8 Impact of Wearable Sensors in the Market 2168.9 Conclusion and Future Scope 218References 218Index 223