L. C. Fung

An investigation of the SAR reduction methods in mobile phone applications

Due to the rapid growth in the use of wireless communication systems, there has been a recent increase in public concern regarding the exposure of humans to radio frequency (RF) electromagnetic radiation. This is particularly evident in the case of mobile telephone handsets. This paper aims to provide an investigation of the effectiveness of various commercially available Specific Absorption Rate (SAR) reduction products and shielding materials that can be externally attached to the handsets in Hong Kong. Also, the SAR values of different mobile phones are measured. Results are compared to the USA and European standards and then characterized for SAR reduction applications.

Electromagnetic Field Radiation of Mobile Phone Inside Metallic Enclosure

A numerical study on the electromagnetic (EM) Held radiation of mobile phone inside metallic enclosure, for human safety aspect, is presented in this paper. The study on the effects of number of human bodies and their positions inside the metallic enclosure on the induced E-field was carried out. Results have shown that the E-field induced on the human head of mobile phone user is not sensitive to the loadings of human bodies inside the metallic enclosure. However, the E-field induced away from the mobile phone user that contributes to the E-field exposure of other people nearby is significantly changed for different human capacities inside the metallic enclosure. Results have also indicated that the E-field induced on the human head of mobile phone user would be increased by 34% when people using mobile phone in proximity to the conducting wall of metallic enclosure.

Effect of internal patch antenna ground plane on SAR

This paper investigates the effect of different ground plane configurations of a typical internal planar inverted-F patch antenna (PIFA) on specific absorption rate (SAR). The effect of the size and the addition of vertical sidewall of the ground plane are investigated; it is found that by varying the ground plane locations and configurations, SAR value can be reduced by 15%

Experimental study of ESD effect on metallic enclosure

Electrostatic Discharge (ESD) can cause serious problems in digital electronic devices. Indirect coupling through apertures on the metallic enclosure to the internal circuitries can also affect the performance of the devices. In this paper, we investigate experimentally the effect of the coupling field through apertures on the metallic enclosure.

Antenna performance of mobile phone and corresponding human exposure inside fully and partially enclosed metallic elevator

The effects of using mobile phone inside both fully and partially enclosed metallic elevators on the antenna performance and the human exposure have been studied by using FDTD numerical method. It has been found that the antenna performance is degraded in all the enclosed metallic elevators studied due to the low radiation efficiency. Results have also shown that, for the human exposure, the electric field strength and the peak SAR of mobile phone user in the fully enclosed metallic elevator is the largest due to the resonance effect.

Investigation of SAR of an internal antenna of mobile phones

This paper presents an investigation of SAR (specific absorption rate) of mobile telephones having an internal antenna structure, and effects on antenna performance due to presence of a human head at close proximity to the mobile telephone. The numerical model for evaluating the SAR values and the antenna performance parameters of a typical internal antenna used in mobile telephones is described, and the results are compared to the measurement results.

Study of using fractional phantom head model on SAR evaluation in mobile antenna design

This paper studies the use of fractional phantom head model on Specific Absorption Rate (SAR) evaluation in mobile antenna design. The SAR value of a duel-band model patch antenna designed with different length and width of ground plane configurations is investigated. It is found that the fractional phantom head model can be used for efficient SAR evaluation in practical mobile antenna design.

Crosstalk study in splitter PCB design of CAT-5 cabling applications

A review of crosstalk in splitter PCB design of CAT-5 cabling system for local area network (LAN) application is carried out Results have shown that design parameters such as separations, lengths and angles of trace pair are the critical parameters on the crosstalk reduction of PCB design, and that a 9 dB reduction of the crosstalk is observed by simply balancing the mutual capacitance between trace pairs.

Analysis of ESD effect due to nonlinearity of metallic enclosures

Electrostatic discharge (ESD) is a problem in electromagnetic compatibility (EMC) that can lead to serious interruption of digital PCB circuit performance. This paper presents an analysis of the noise induced in the digital circuit and characterizes the ESD effect as the nonlinear magnetic saturation property of metallic enclosures. The current distribution of the metallic enclosures is first evaluated, and the noise voltage induced in the PCB within the enclosed space is then estimated.

Assessment of radiated immunity of C-band satellite TV receiving station in Hong Kong local environment due to UWB interference

In this paper, the radiated immunity of C-band satellite TV receiving station to UWB interference in the Hong Kong local environment has been investigated. Results have indicated that the UWB interference, including degradation in the picture quality and in the BER after correction, cannot be identified for any separation distance large than 12 m, even if the e.i.r.p of UWB device is at -41.37dBm/MHz. However, the interference power received at the C-band antenna could be larger in some cases, such as operation of multiple UWB devices with aggregate effect, and when the UWB device is located within the main beam pattern or at different angles.