Optimal Placement of Individual LF Antennas on Each Axis in a Small Mobile Device Through a Systematic Optimization Process

Abstract

This letter proposes the optimal placement of individual low-frequency (LF) antennas on each axis integrated in a small mobile device platform to maximize the coverage range of the communication link. To achieve the maximum coverage, considering small platform effects, a systematic genetic algorithm optimization process was conducted using a readable volume metric as a cost function. A readable volume of 34.5 m(3) at the optimum locations of the individual LF antennas was obtained compared with that of 21.6 m(3) for the bundle of LF antennas. To verify the results, Poynting vector measurements were performed using LF antennas located at optimal positions inside the copper mobile device platform. The Poynting vector strengths at the range of 30 cm were -138.9, -140.7, and -138.7 dBW/m(2) along the x-, y-, and z-axis, respectively.