Contents I. Introduction
The rapid growth of mobile communications and the adoption of standards such as 4G and 5G have created an increasing demand for multi-band or wideband antennas [1], [2]. These technological advancements have been designed to harness the potential of MIMO (Multi-Input Multi-Output) operation, thereby enhancing the capacity and reliability of wireless networks [3]. However, the ongoing miniaturization of modern smartphones and their sleek, elegant designs pose significant challenges for integrating multiple antennas on small printed circuit boards [4], [5]. The close proximity of antennas leads to high coupling, reducing their isolation and impacting the overall performance of the device. To address these challenges, various methods have been explored to improve isolation between antennas. Techniques such as neutralization lines, metamaterials, deflector arrays, and slot techniques have shown promising results in reducing mutual coupling and enhancing performance [6]–[7]. Additionally, innovations in antenna design, including compact structures and specific radiating elements, have helped mitigate interference while maintaining high performance [8]–[9]. These developments are crucial to meet the stringent demands of modern communications. In this article, we address these challenges by proposing an innovative solution for a compact mobile communication device. We introduce a unique dual-band antenna operating at 2.6 GHz/3.6 GHz. This antenna consists of an F-shaped monopole with a complementary slot of the same dimensions, dedicated to creating the lower frequency band. Additionally, we have closely positioned two antennas on a mm2 printed circuit board. The slot technique is implemented to enhance isolation between the ports. Simulations have been conducted to assess the performance of our antenna in terms of S-parameters, radiation pattern, MIMO parameters, and efficiency.
