Design of a multiband internal antenna for mobile application

The multiband internal antenna for mobile application is proposed. The proposed antenna has wide bandwidth of about 400 MHz (2.3 GHz ∼ 2.69 GHz) for MIMO antenna. The return loss(S
11
and S
22
) is higher than 10 dB and isolation characteristic(S
12
and S
21
) is less than −20 dB over the frequency band of interest. The separate monopole antenna has return loss of higher than 10 dB over WCDMA band. The measured antenna gain is higher than 0 dBi and measured efficiency is greater than 60 %.