On Q-factor Bounds for Lossy Embedded Antennas in Electrically Small Devices

摘要

In this paper we investigate a method to determine the best available bandwidth for small embedded antennas. The available bandwidth depend both on the size and the position within a device, but also on the ohmic losses in the structure. Here we use that solutions to a non-convex optimization problem to predict the available bandwidth for a range of surface resistances. The optimization problem utilizes stored energies, and it is phrased as a current optimization problem. We illustrate the method by comparing the results with embedded antennas in a small IoT terminal. We show that an optimized embedded come rather close to the bounds.