In this paper, a reliable small-signal model parameter extraction method for GaN high electron mobility transistor (HEMT) on Si substrate has been developed and validated with respect to different gate width devices. The main advantage of this approach is its accuracy and dependency on only pinched-off and unbiased S-parameter measurements. The developed procedure shows reliable and physically relevant results for the investigated devices and scaled with the gate width. A very good agreement is obtained between small-and large-signal simulations and measurements of the considered GaN HEMTs.

This paper presents experimental results of overwater radio path loss in the 4.4 to 5.0 GHz band. These measurements involve horizontal and vertical polarizations. Based on electromagnetic theory, a deterministic two ray model that mimics measurements is developed. The model can predict the received power level for all distances lower and higher than the critical distance. The model is consistent with measurements in MIMO modes using any kind of linear polarized antennas.