A compact CPW-fed band-notched UWB-MIMO flexible antenna for WBAN application

A compact coplanar waveguide (CPW)-fed band-notched ultra-wideband (UWB) multiple-input multiple-output (MIMO) flexible antenna on liquid crystal polymer (LCP) substrate is designed. It is composed of two orthogonal elements, tampered feeder and asymmetric ground plate. To improve the port isolation (S-21), an inverted F-shaped branch is added. The measurement results demonstrate that the antenna has achieved impedance bandwidths (S-11 < -10 dB) of 890 MHz (2.4-11.3 GHz) except one rejected band of 3.1-4.3 GHz, and the port isolation is higher than 23 dB. The influence of human body and bending have also been experimented. The results show that the designed antenna has satisfactory bandwidth, high isolation, sound gain in working bands, the characteristics of flexibility and low specific absorption ratio (SAR) values, which indicate the excellent application in the WBAN systems.