tailieunhanh - WILEY ANTENNAS FOR PORTABLE DEVICES phần 2

mật độ, hằng số điện môi, các yếu tố mất điện môi và hình dạng phức tạp. Đây là một tình huống đó đã được đơn giản hóa để cung cấp cho các nhà thiết kế thiết bị cầm tay hướng dẫn kỹ thuật mà họ có thể làm việc, cho các mục đích quy định một tiêu chuẩn vật lý đầu ảo được sử dụng trong các cơ quan nội tạng được đại diện bởi một chất lỏng đồng nhất với định nghĩa tính chất điện. . | 14 Handset Antennas Table SAR limits for the general public specified by various administrations. Australia Europe USA Japan Taiwan China Measurement ASA ICNIRP ANSI TTC MPTC method ARPANSA EN50360 2004 ARIB Whole body W kg W kg W kg W kg W kg Spatial peak 2W kg kg kg 2 W kg kg 1 W kg Averaged over 10 g cube 10 g cube 1 g cube 10 g cube 1 g cube 10g Averaged for 6 min 6 min 30 min 6 min 30 min densities dielectric constants dielectric loss factors and complex shapes. This is a situation which has to be simplified to provide handset designers with engineering guidelines with which they can work so for regulatory purposes a standard physical phantom head is used in which the internal organs are represented by a homogeneous fluid with defined electrical properties. With a handset positioned beside the phantom and with its transmitter switched on the fields are probed inside the phantom. They are translated into SAR values and the pattern of energy deposition is mapped to determine the regions with the highest SAR averaged over 1g and 10 g samples. Simulations are often carried out using this standard head but more realistic information is obtained using high-resolution computer models based on anatomical data. Extensive investigation of possible health effects of RF energy absorbed from mobile phones has been carried out in many countries. Current results suggest that any effects are very small at least over the time period for which mobile handsets have been in widespread use. Those interested should consult the websites of the major national occupational health administrations and medical journals. The responsibility of the antenna designer is to ensure that the user is exposed to the lowest values of SAR consistent with the transmission of a radio signal with the power demanded by the network. Hearing aid compatibility. Handsets operating with time-division multiplex protocols such as GSM emit short pulses of radio