Low Power Near Field Communication Methods for RFID Applications of SIM Cards

Abstract

Power consumption and communication distance have become crucial challenges for SIM card RFID (radio frequency identification) applications. The combination of long distance 2.45 GHz radio frequency (RF) technology and low power 2 kHz near distance communication is a workable scheme. In this paper, an ultra-low frequency 2 kHz near field communication (NFC) method suitable for SIM cards is proposed and verified in silicon. The low frequency transmission model based on electromagnetic induction is discussed. Different transmission modes are introduced and compared, which show that the baseband transmit mode has a better performance. The low-pass filter circuit and programmable gain amplifiers are applied for noise reduction and signal amplitude amplification. Digital-to-analog converters and comparators are used to judge the card approach and departure. A novel differential Manchester decoder is proposed to deal with the internal clock drift in range-controlled communication applications. The chip has been fully implemented in 0.18 µm complementary metal-oxide-semiconductor (CMOS) technology, with a 330 µA work current and a 45 µA idle current. The low frequency chip can be integrated into a radio frequency SIM card for near field RFID applications.

An Improved Design and Implementation of a Range-Controlled Communication System for Mobile Phones

“…Assuming that two coils of the transmitter and receiver have an interval of x . The voltage induced in the receiver coil is as follows [ 20 ]: …”

“…If the die size of the LF receiver chip is small, the LF receiver chip can have a package-in-package (PIP) bonding design with the SE chip, which can save some space to increase the tuning coil number. The die size of the LF receiver in previous work [ 20 ] was too large to perform PIP bonding with the SE chip. One method to obtain a larger x is to obtain a higher ; another method is to decrease the signal loss in analog frontend circuit of the LF receiver.…”

“…HF communication is started only when LF is activated, and the communication distance is constrained under 10 cm. Our previous work [ 20 ] presents a design for an LF receiver chip with a die size of 1850 m by 1650 m and a working current of 330 A; it has a communication distance of 7.8 cm in phones with a non-metallic shell. However, some new mobile phones were produced in recent years that only accept the smallest nano-card.…”

“…The inner card of SIM card site has weakened LF signals, and the metal shell makes it even worse. The SIM card’s working distance based on the LF receiver chip in [ 20 ] decreases to less than 0.5 cm in these new mobile phones. The large die size makes it difficult to increase LF coil turn number in nano-SIM cards.…”

“…The large die size makes it difficult to increase LF coil turn number in nano-SIM cards. Besides, to obtain a better LF communication distance, all amplifiers in [ 20 ] should set to the largest gain, and the working current is much larger than 330 A. Although it has an idle mode with 45 A current consumption, in RCC application, the LF receiver is used to wakeup HF, and so is in working mode all the time.…”