A theoretical and experimental study of dielectrically loaded antennas and their contribution towards low-SAR

Multi-band material loaded low-SAR antenna for mobile handsets

“…The benefits were shown to be applicable to a variety of shapes by extensive simulation of rectangular and other irregular shaped antennas using Flomerics' Micro-stripes™ based on TLM. Analysis showed maximum possible bandwidth and efficiency for any particular mode was achieved when the material's permittivity and permeability values were roughly equal [1,2]. For example, if the permittivity and permeability product of a ferrite loaded dielectric block excited by a dipole is kept constant at 36, then maximum bandwidth and efficiency is achieved when ε r = μ r ≅ 6.…”

“…For example, if the permittivity and permeability product of a ferrite loaded dielectric block excited by a dipole is kept constant at 36, then maximum bandwidth and efficiency is achieved when ε r = μ r ≅ 6. Further studies showed the antenna's SAR was mainly dependent on its orientation with respect to the head and would dramatically reduce when the axis of symmetry of the antenna was orthogonal to the head [3]. With regards to a monopole, the ground plane is parallel to and the monopole is perpendicular to the head.…”

“…Initial studies on dielectric spherical resonators excited by small wire probes or loops based on analytical models, highlighted the benefits of introducing ferrite material into the resonators [1]. The benefits were shown to be applicable to a variety of shapes by extensive simulation of rectangular and other irregular shaped antennas using Flomerics' Micro-stripes™ based on TLM.…”

“…It has been previously demonstrated that by including ferrite material, antenna size can be reduced while maintaining good efficiency and bandwidth [1]. High efficiencies are generally accompanied by high SAR values but careful orientation of the antenna can overcome this obstacle [2].…”

Investigation into the realisation of a low-SAR, dual mode material coated antenna for mobile handsets

“…More recently it has been shown that a material having both a permittivity and permeability is able to reduce antenna size while maintaining the bandwidth and efficiency [I, 21. The introduction of permeability also gives additional design freedom regarding the magnetic and electric composition of the near fields and this has implications for the reduction of the Specific Absorption Rate (SAR) [2,3]. In the present paper the ability of this new ferrite-based antenna concept to operate in dual mode is examined and simulations illustrate the significant increase in bandwidth that can be obtained.…”