Broadband Equivalent Circuit Model for Capacitive Coupling Element–Based Mobile Terminal Antenna

In this letter, it is shown how the behavior of a capacitive coupling element (CCE)-based mobile terminal antenna can be modeled at the UHF band as a combination of the separate wavemodes of the structure. The proposed equivalent circuit model improves the general understanding of the operation of the antenna structure. It can be used for analyzing the combined performance of the capacitive coupling element and terminal chassis, but it also helps in analyzing how different parts of the antenna structure contribute to the impedance and radiation.