Low SAR Ferrite Handset Antenna Design

Professor Jim James...a great researcher and motivator in the field of antennas

“…In addition, he was very interested in the interaction of human tissue with EM radiation, as he realised the importance of the issue both to users and manufacturers. Consequently, he combined the two topics and was concerned with the application of a dielectric-ferrite mix in the design of a multiband, low SAR mobile phone antenna [38]. The benefits from the addition of ferrite compared to dielectric alone were examined using both analytical and experimental methods.…”

“…The antenna comprised of a block of material with ε r~µr excited by a monopole to ensure a pattern null towards the head, see Figure 5. Using extended developmental simulation work, it was possible to translate the aforementioned attributes into a quad-band design [38], which combined excellent band coverage (GSM 1800, 1900, UMTS, Bluetooth) and simple design with high efficiencies (~37%) and extremely low SAR (<0.1W/kg). An alternative handset antenna design was also simulated with differences to the metallisation used and the position of the source.…”

“…The final multi-band antenna design simulated, was a tri-band handset antenna design (GSM 1800, 1900, UMTS), using currently available material with reduced permeability (εr = 24.1, µr = 2) [38]. The efficiencies attained were decreased compared to the quad-band designs, however, the results were encouraging considering that this material is used for screening purposes.…”

Current leakage failure of conformally coated electronic assemblies

“…Over recent years there has been exponential growth in radio frequency (RF) technologies such as mobile communications, data transfer via RF transmission, wireless computer connectivity, remote sensing and autoidentification and data capture (AIDC) [1,2]. Such wireless enabled applications are inherently linked to operation in harsh environments, since the in-service conditions of a mobile device cannot be specified as tightly as for a fixed device.…”

Microstrip patch antennas on substrates with metallic inclusions

“…It was hypothesized that further improvements could be obtained by using a smooth transition between local dielectric regions as could be achieved with artificial dielectrics [17][18][19]. A small size, high efficiency antenna can be achieved by using an as yet unrealizable material with equality of permittivity and permeability [20]. An initial study by the authors gave preliminary insight into the behaviour of patch antennas on synthetic media with dielectric inclusions [11], [21].…”