Study on effective pattern of magnetic sheet attached on NFC antenna

Abstract

In case of payment system with NFC (Near Field Communication)/HF-RFID (Radio Frequency IDentification) installed into the smart-phone, NFC antenna's communication performance at 13.56MHz is deteriorated by the battery case or circuit boards. To solve this problem, the magnetic sheet with high permeability is inserted into the NFC/HF-RFID antenna and metal object. Thin magnetic compound or sintered ferrite has been used as the high permeability sheet. However, these sheet thickness could not be suppressed to improve the NFC/HF-RFID antenna's performance. In order to make thickness of these materials thinner, we propose amorphous magnetic sheet. Besides because the loss of amorphous magnetic sheet is large, that loss suppression technique is also proposed.