Antenna Pulls In NFC Applications

Suitable for mobile telephones and portable wireless devices, a new stamp-sized antenna from Pulse, a Technitrol Company, operates in the 13.56-MHz near-field-communications (NFC) and is integrated with a second antenna with cellular frequency ranges of 824 to 960 MHz and 1710 to 2170 MHz for wireless connectivity using GSM and WCDMA in a single device. The stamp antenna, which measures 15 x 20 x 5 mm, can read small radio-frequency-identification (RFID) tags with diameters from 15 to 65 mm at distances from 5 to 20 mm. The RoHS-compliant NFC antenna operates at 13.56 MHz with an H-field of 1.5 A/m and a return loss of 25 dB. It is integrated with a cellular antenna with 58-percent efficiency from 824 to 960 MHz and 59-percent peak efficiency from 1710 to 2170 MHz. Both antennas have 50-Ohm impedance and operating temperature range of -40 to +80 deg.C. The separate NFC antenna can be integrated into a mobile device's back cover with a snap-fit structure.