Towards 600 MHz LTE smartphones via tunable magnetodielectric Printed Inverted-F Antennas

The use of magnetodielectric reconfigurable antennas on smartphones was investigated aiming to meet the requirements of the lower bands of current 4G standards and beyond. Since physical dimensions are constrained by the size of the mobile terminal, a reconfigurability mechanism based on partial magnetodielectric substrates and superstrates was studied in order to shift the resonance frequency lower while maintaining low system complexity. A printed inverted-F antenna (PIFA) was used to demonstrate continuous tuning, as opposed to the discrete tuning states of other methods, e.g., aperture tuning by means of switched capacitors. The numerical analysis of the PIFA started with lossy, isotropic ferrites, and then it elevated to gyromagnetic anisotropy. It was found that some of the benefits of tunable magnetodielectric loading are the ability to cover the 600–960 MHz band with just 3–5 sub-bands requiring realistic values of permeability, whereas an adequate radiation efficiency is maintained throughout the band.