Antenna selection for testing the computer-telephone-integration near-field interference

Computer-telephone-integration (CTI) interference may happen when a mobile phone is operated adjacent to a digital device. This device could be a tablet or a laptop computer, the mobile phone nearby is used as a gateway for the device, and therefore the CTI interference from the mobile phone may disrupt the device. To evaluate the device immunity to such an interference, a near-field testing should be performed. For this testing, the transmitting antenna representing the mobile phone should be carefully selected since the interference is a near-field effect and the antenna performance could be affected reversely by the nearby device. In this paper, the optimal type of antenna is suggested. This type of antenna shows to be insensitive to the nearby device. Both simulated and measured results are obtained to support the suggestion.