A Wideband Decoupling Technique for Two Inverted-F Antennas Using a Capacitively Loaded Ground Cut

In this letter, an efficient wideband decoupling technique is introduced for two inverted-F antennas (IFAs). By introducing a capacitively loaded ground cut, two extra coupling paths can be exploited and co-tuned to mitigate the mutual coupling between two IFAs at two frequencies. Therefore, two transmission zeros can be obtained so that a wideband and deep decoupling is achieved. An equivalent circuit is presented for the proposed antennas to reveal the decoupling mechanism. Three examples are designed to justify the proposed method, showing that wideband isolation and impedance matching are obtained with 19.6% fractional bandwidth for 30 dB isolation and 11.2% for 40 dB isolation. Moreover, the average total efficiency is 86%, with the size of the decoupling structure only about 0.04 × 0.06λ 2 .