Self-Curing Decoupling Technique for Two Inverted-F Antennas With Capacitive Loads

A new concept named the self-curing decoupling technique is proposed for the first time to reduce the mutual coupling between two closely located inverted-F antennas (IFAs). The decoupling technique only requires a capacitive load on the shorting arm of each coupled IFA without connecting a circuitry or inserting a physical structure between the two coupled antennas. The capacitive load occupies very little space and is frequency-insensitive; therefore, the decoupling technique is a very favorable choice for low-frequency applications. Network analysis is presented to mathematically justify the working mechanism and to provide a design guideline. Several practical cases of two IFAs situated at different positions on the periphery of a PCB board are studied. The experimental results show that with the decoupling technique, significant improvements in the port isolation (from 10 to 20 dB), antenna correlation coefficient (from 0.25 to 0.05), multiplexing efficiency (from 46% to 60%), and above all the system throughput (1.2 and 0.8 dB power saving in Urban Microcell and Urban Macrocell channels, respectively) can be obtained.