Impact of Dielectric Loss on the Modal Tracking in Characteristic Mode Analysis of Planar Antennas

The performance of most of the planar antennas, such as efficiency, bandwidth, and gain, is strongly influenced by the dielectric properties of the materials employed in their construction. Among these properties, the loss tangent, a measure of dielectric losses due to material polarization, plays a crucial role in determining how effectively an antenna radiates or receives signals. This paper investigates the impact of loss tangent on the performance and modal characteristics of two commonly used antenna types: patch and slot antennas. The analysis presented in this paper highlights importance of performing the modal analysis in realistic scenerios, importance of distinguishing between spurious and radiating modes. Through a combination of simulations and experimental data, the study highlights how variations in the loss tangent affects the characteristic modes, tracking and antenna performances.