Printed Multi-Band MIMO Antenna Systems and Their Performance Metrics [Wireless Corner]

Multiple-input-multiple-output (MIMO) antenna systems are a key enabling technology for modern fourth-generation (4G) wireless systems. The need for higher data rates for multimedia applications within the limited bandwidth and power levels led the way to the use of multiple antennas at the receiver and transmitter ends. Printed MIMO antenna systems, supporting multiple bands, including the lower band of the 4G wireless standard (LTE), pose a challenge in terms of available size. In this work, we start by defining the new required metrics to characterize MIMO antenna systems. We then present several recent printed multi-band MIMO antenna systems, along with some isolation-enhancement mechanisms that are used in these closely packed antennas.