A multiband monopole antenna using a double-tuned wheeler matching network

A double-tuned matching network is proposed, which replaces one of the resonant circuits in a Wheeler matching network with a λg/2 transmission line in order to achieve broadband and multiband matching performance. The multiband Wheeler matching network is then applied to a circular monopole antenna, and it is demonstrated that a compact, multiband and highly efficient antenna can be achieved. The antenna operates in the frequency ranges of 1.90–4.20 GHz and 6.05–6.53 GHz, has a total size of 20 × 50.3 × 1.59 mm and exhibits efficiencies in the order of 90%.