Self-Decoupled Coupled Line Antenna Pair (CLAP) with Reconfigurable Wideband for Mobile Terminals

A new type of reconfigurable wideband self-decoupled coupled line antenna pair (CLAP) is proposed for mobile terminals. The CLAP adopts the coupled transmission line with two separated opposite ports and two open ends, which is naturally built-in with the band-isolation characteristic when its electrical length is half a wavelength. Since this coupled line retains the intrinsic self-isolation between two ports even for asymmetric structures, the CLAP doesn't require balanced feeding ports or a symmetric environment. To enhance the working frequency bandwidth, an electromagnetic capacitive (EC) feed structure is proposed with two reconfigurable states covering the N77 (3.3-4.2 GHz) and N79 (4.4-5 GHz) bands, respectively. The measured isolations within two reconfigurable states are higher than 11 dB and 17.5 dB, respectively. The measured total efficiencies of both antennas in two working states are 58%-88% and 61%-88%, respectively. The results demonstrate that the proposed CLAP design concept will provide a simple and wideband self-decoupled antenna for MIMO application.