A Coupled Resonator Decoupling Network for in-device coexistence of two collocated antennas

The concept of Coupled Resonator Decoupling Network (CRDN) is applied to the interference suppression of two collocated antennas operating in two adjacent frequency bands. A microstrip version of a second-order CRDN is designed according to the S-parameters of the two coupled antennas. A specific scenario of the coexistence of TD-LTE and Wi-Fi radios is studied. The isolation improvement using the CRDN is more than 15 dB within the band of interest. The technique is general and can be applied to all kinds of coexistence problems in a mobile terminal.