Mobile Phone Antenna Performance and Power Absorption in Terms of Handset Size and Distance from User’s Head (original) (raw)

Mobile Handset Radiation Efficiency as a Function of the Antenna Position Relative to the Human Head

The radiation efficiency of a mobile handset as a function of its relative position to the user's head, has been investigated. The study was based on theoretical results taken through electromagnetic modelling using MoM and on experimental results obtained by a measuring procedure using a mock-up handset and a phantom head in an anechoic chamber. The distance between antenna and the head as the handset is moving away from the head in the horizontal direction is found to be the main factor affecting the radiation efficiency in comparison with the movement of the handset vertically or horizontally on the "ear to nose" direction.

Dependance of the EM power absorbed in the head of a mobile phone user on the phone-head distance

Measurements and numerical simulation of 3D radiation patterns of a mobile phone model in the presence of a human head phantom have been performed. The relative amount of the EM power absorbed in the head was obtained for several distances of the phone. It was found that significant reduction of the absorbed power (about 50%) could be achieved by moving the phone for only 1 cm away from the head. Agreement between theoretical and experimental results was found to be very good.

Interaction Between GSM Handset Helical Antenna and User's Head: Theoretical Analysis and Experimental Results

The Environmentalist, 2005

The performance of a cellular phone commercial helical antenna at 900 MHz band, both in free space and in the presence of a human head phantom was studied. Numerical simulation of the phone model for the latter case has been performed giving 3D radiation diagrams. The effect of the phantom head on radiation diagrams is presented. The relative amount of the EM power absorbed in the head was obtained for several distances of the phone. Measurements were carried out in a RF anechoic chamber using standard horn antennas and a calibrated measuring system. Absolute radiation patterns of the antenna gain were obtained in the three principal planes. Significant reduction of the absorbed power could be achieved just by moving the phone 1 cm away from the head.

Analysis of Mobile Phone Antenna Performance within the Head and Hand Phantoms

International Journal on Advanced Science, Engineering and Information Technology, 2011

This paper proposes the effect of the hand-hold position on the electromagnetic (EM) wave interaction of a candy bar type and clamshell type cellular handset and a human head and hand is investigated. The human hand influences the performance of terminal antennas, and it is the main cause for absorption and detuning. In spite of its importance in mobile-phone design and validation processes, it is still complicated to take it into account because a lack of knowledge in the area. In this paper, a rigorous investigation methodology is described for the study of candy bar, and clam shell mobile phone CAD model is used to numerically investigate the effect of hand phantom of mobile phone antenna radiation performance. The simulation results show that mobile phone grip styles of the hand phantom material properties, wrist and length, and hand phantom sizes and different positions is the important parameter to antenna performance. The grip style has direct implications in the definition of phantom head. The preference of the handset with respect to the side of the user's head depends on the mobile phone form factor and size. The results established high reliability and suitability for providing decision rationale for the design of complex high-end multi-band mobile phones. Keywordsantenna closeness factors, finite-difference time-domain (FDTD) method, hand phantom, mobile communication.

The Interactions Between the Mobile Handset Antenna of Various Types and the Human Head

One lingering concern is the effect of the radiation produced by the mobile handset antenna on the human head. This topic has been studied widely, but still there is no definitive answer. Since mobile telephones are typically used in close to the human head, significant levels of power can be absorbed by the head, the primary effect is to cause local heating of the brain and head tissues. This is of concern to some people who work continually with mobile telephones, and some form of ''preventative'' research should be done. This paper describes some kinds of models of antennas (dipole, monopole and patch antennas) and human, and the calculation of the Specific Absorption Rate (SAR) in the human head at 1800 MHz. Also, this paper studies the effect of the human head model on the return losses of these models of the antennas. The obtained results show that at the same frequency, the patch antenna induces SAR in the human head of smaller values than that induced by dipole and monopole antennas. In addition, the return loss of the patch antenna is affected greatly by the presence of the human model, when it is compared with the return losses of the dipole and monopole antennas.

Influence of the Human Head in the Radiation of a Mobile Antenna

2009

The big proliferation of mobile communication systems has caused an increased concern about the interaction between the human body and the antennas of mobile handsets. In order to study the problem, a multiband antenna was designed, fabricated and measured to operate over two frequency sub bands 900 and 1800 MHz. After that, we simulated the same antenna, but now, in the presence of a human head model to analyze the head's influence. First, the influence of the human head on the radiation efficiency of the antenna has been investigated as a function of the distance between the head and the antenna and with the inclination of the antenna. Furthermore, the relative amount of the electromagnetic power absorbed in the head has been obtained. In this study the electromagnetic analysis has been performed via FDTD (Finite Difference Time Domain).

Factors Influencing the EM Interaction between Mobile Phone Antennas and Human Head

… Information and Communication Technology and Its …, 2011

This paper presents a procedure for the evaluation of the Electromagnetic (EM) interaction between the mobile phone antenna and human head, and investigates the factors may influence this interaction. These factors are considered for different mobile phone handset models operating in the GSM900, GSM1800/DCS, and UMTS/IMT-2000 bands, and next to head in cheek and tilt positions, in compliance with IEEE-standard 1528. Homogeneous and heterogeneous CAD-models were used to simulate the mobile phone user's head. A validation of our EM interaction computation using both Yee-FDTD and ADI-FDTD was achieved by comparison with previously published works.