2019 49th European Microwave Conference (EuMC) | 2019
Antenna Array Driven by Non-Isolated Power Amplifiers for MIMO Applications
Abstract
In this paper, the effect of antenna coupling in an active array on the integrated power amplifiers (PAs) is studied. It is found that for multiple-input multiple-output (MIMO) applications some antenna elements inputs can experience negative impedance. When isolators between antennas and PAs are missing, which is preferable in highly integrated millimeter-wave (mm-Wave) massive MIMO transmitters due to the fact that isolators are bulky and integration-incompatible, this negative impedance can cause PA oscillating/damaged, or at least non-functional. This non-linear problem is studied theoretically using an example of a coupled antenna array driven by Doherty PAs. In addition, the experimental results validate the existence of the negative impedance and reveal its relationship with the array excitation and PA non-linearity.