Electromagnetic Interference Immunity Testing of Medical Equipment to Second- and Third-Generation Mobile Phones

There has been concern regarding the effect of electromagnetic interference (EMI) on medical equipment from portable wireless communication devices in hospitals in Hong Kong. The latest third-generation (3G) mobile communication system was fully implemented in 2004. As a result, an investigation to examine the EMI issues surrounding medical equipment, due to interference from communication devices, including GSM900, PCS1800, and 3G digital mobile phones, has been carried out. A statistical analysis has shown that the cumulative distribution function of base station signals within the hospital´s environment follows the Weibull distribution for all three mobile phone systems in Hong Kong and that the percentage of failed medical equipment increases with a correlation of an increase in the radiated power level of the mobile phone. This is a direct result of a weakening in base station signals. The EMI effect from 3G mobile phones is also found to be four to eight times lower than that of the GSM900 and PCS1800, in locations inside the hospitals with weak base station signal strength, such as a basement or in operation theaters.