Designing Capacitive Coupling Element Antennas With Bandwidth Estimators

Ranking different nonresonant antenna structures is impossible, if their achievable potential with a matching circuit is ignored when designing the radiating parts. Novel bandwidth estimators offer an efficient tool to seek optimal antenna structures. This letter systematically analyzes a certain representative set of capacitive coupling element antennas and gives guidelines for finding the best antenna structures. The obtained results for one-element structures are applied to design a two-element antenna for the bands 0.7-0.96 and 1.71-3.5 GHz. A prototype demonstrates that the choices made based on the theoretical study and ideal simulations steer the antenna solution to produce the required performance. Consequently, the presented systematic approach may promote the development of antennas in future.