Decoupled WWAN/LTE antennas with an isolation ring strip embedded therebetween for smartphone application

An integrated antenna array comprising two decoupled multiband WWAN/LTE antennas having an isolation ring strip embedded therebetween and all disposed on a same FR4 substrate of small size 10 × 70 mm 2 is presented. The two decoupled antennas cover the 824–960/1710–2690 MHz bands for the GSM850/900 and GSM1800/1900/UMTS/LTE2300/2500 operations and are promising to be mounted at the bottom edge of a smartphone for dual wireless wide area network (WWAN) operation for dual‐talk function or for long term evolution (LTE) multiple‐input multiple‐output operation. The measured transmission coefficient S 21 between the two antennas is less than −15 dB over both the 824–960 and 1710–2690 MHz bands, and the envelop correlation coefficient is less than about 0.03 over both bands. Port‐decoupling of the two antennas is obtained because the excited surface currents on the system ground plane of the smartphone between the two antennas are decreased owing to the isolation ring strip attracting some of the same. In addition to good isolation obtained, the antenna efficiencies are better than about 40 and 50% over the lower and upper bands, respectively. Details of the decoupled WWAN/LTE antennas are described.