## 1 Introduction  
In the early 1950s, the concept of microstrip patch antennas emerged. Printed circuit board (PCB) technology gained momentum during the 1970s. After this era, patch antenna technology further accelerated and advanced into diverse fields. To date, among the numerous types of antennas, patch-type antennas are the most prominent. People attribute their popularity to their lightweight construction, low-profile design, and cost-effectiveness, as well as their planar geometry, portability, and easy integration into modern electronic systems. In applications requiring compact efficient wireless solutions, microstrip antennas are chosen. They are easy to conform to, can be used in arrays, and are simple to fabricate and integrate with microwave monolithic integrated circuits (MMICs). Microstrip patch antennas are easy to construct using a variety of feeding techniques, such as offset, inset, and probe feeds. They come in diverse types of patch structural shapes, including hexagonal, square, circular, triangular, and rectangular. These antennas have been widely used in applications such as radio frequency identification (RFID), broadcast radio, mobile systems, global positioning systems (GPS), television, multiple-input multiple-output (MIMO) systems, vehicle collision avoidance systems, satellite communications, surveillance systems, direction finding, radar systems, remote sensing, missile guidance, and many more. In recent years, many countries have struggled with the rising cost of long-term healthcare and wellness services. According to the World Health Organization (WHO), the global population aged 60 and older has grown to 1.4 billion. Projections indicate that by 2050, this number will increase to 2.1 billion. Additionally, the population of people aged 80 and older is expected to triple between 2020 and 2050, reaching 426 million [1]. New developments in medicine and advancements in fighting disease are important milestones for society and medicine but pose a challenge to global healthcare systems. As demand for healthcare services is on the rise, the development of new strategies, regulations, and procedures is required for efficient resource utilization. New inventions in portable, wireless, and electromagnetic sensor technologies offer great promise for future research and therapeutic applications targeting various parts of the body [2]. These modern technologies have potential in different fields such as sports, gaming, and healthcare. Medically known as wearable or on-body antennas, their popularity had been boosted due to their easy attachment to the body and subsequent remote operation. Their structure is lightweight, thin, flexible, and able to twist; hence, they are adaptable to irregular human body surface topologies [3]. Future generations could take the form of compact, modular wearable sensors and signal processors that transmit health data to portable devices. Wearable antennas can serve as health monitoring systems. These systems enable individuals to closely track changes in their vital signs and provide feedback to help maintain optimal health conditions. When integrated into telemedical systems, wearable health monitoring systems can also alert medical staff to life-threatening changes in a patient's condition [4]. Figure 1 illustrates the growing prevalence of wearables and offers insight into the future of wearable technology. Figure 1: Monitoring day-to-day activities using a wearable antenna. WBANs are widely utilized for various real-time health monitoring applications. These networks rely on wearable antennas to transmit and receive data for healthcare-oriented devices [5]. In recent years, significant advancements in wearable electronics have driven research into body-conformal antennas. It has become increasingly important to frequently monitor several key physiological indicators, such as heart rate, blood glucose levels, blood pressure, and electrocardiograms (ECGs), due to their critical role in human health.