earticle

영어

In this paper, a 4-port broadband mobile phone multiple input multiple output (MIMO) antenna is designed and implemented for use in femto cell communications. The assembly consists of 4 antennas with one main antenna that covers the entire design band and 3 sub antennas that cover the data communication bands. Each of the antennas is located on the top and bottom corners of the bare board, and we tested them on a PC board with the same board ground circumstances as practical phone ground. The main antenna operates in the CDMA, GSM, LTE class 2~3 and class 33~34 service bands, and the sub antenna operates in the LTE class 1~4, and Wibro band for data communications. The voltage standing wave ratio (VSWR) was less than 3:1, and the maximum isolation between the antennas was -8.5dB over the entire design band. The average gains for the main antenna were measured from -2.48 to -0.54dBi, with efficiencies from 56.45 to 88.3% while those for the sub antennas were between -1.96 to -1.2dBi and 63.75 to 75.92%, respectively. The envelop correlation coefficient (ECC) for the MIMO system was under 0.148 over the entire data communications band.