1. Introduction
Modern developments in 5G wireless communication systems require highly integrated, geometrically compact radio frequencies, microwave circuits, and modules featuring broadband and multi-band functionalities. The most widely used frequency bands for commercial wireless communications such as mobile phones and wireless Internet connectivity are allocated in the low microwave frequency ranges of up to 6.0 GHz [1], covering popular bands of 900 MHz, 1.9 GHz, 2.45 GHz, 3.5 GHz, and 5.8 GHz. Within the advancing realm of fifth-generation (5G) wireless communication networks, operational frequencies may extend to 28 GHz, 35 GHz, and even up to 57–71 GHz [2]. Consequently, a significant disparity in frequency arises between existing and upcoming wireless communication infrastructures. In recent years, many high-performance dual-band power dividers, filters, and antennas…
