13.56MHz RFID reader SiP with embedded Antenna.pdf

1、13.56MHz RFID reader SiP with embedded Antenna Jikon Kim#1, Hyunsik Kim#1, Jaewhan Kim#1, Junghyun Cho#1, Gawon Kim*2, and Shiho Kim#1 # Dept. of Electrical Engineering, Chungbuk National University, Chungbuk, 361-763, Korea * Dept. of Electrical Engineering, KAIST, Taejeon, 305-701 Korea jkkim, hsk

2、im, jhkim, jhcho, shihocbnu.ac.kr, gawon4ueeinfo.kaist.ac.kr Abstract We have proposed and implemented 13.56Mhz multi- protocol RFID reader SiP with embedded loop antenna. The proposed SiP RFID reader has been designed to support 13.56MHz RFID protocols of ISO14443 A/B type, ISO15693 and ISO 18000-3

3、 standards. The operating mode is controlled by embedded MCU core, and the mode can be selected by users. The area of implemented SiP is 30mm 30mm with 4 substrate layers. The implemented reader SiP operates at single supply voltage of 3.3V. The current consumption is 200uA in idle mode and 100mA at

4、 active mode. I. INTRODUCTION There has been a great interest in Radio Frequency Identification(RFID). 13.56MHz RFIDs are mostly used in E-commerce, credit card, mobile phones, personal administration, PDAs, ID tags, transportation and fare collection, etc1-5. The international standards for 13.56MH

5、z RFIDs are ISO14443 type A/type B, ISO15693 and ISO18000-31-3. Fig. 1 shows Key parameters of signal interface between transponders and interrogator for 13.56MHz RFIDs. The system communicates in half duplex mode. The interrogator uses a carrier frequency of 13.56MHz, both for transferring energy a

6、nd data. The inductively coupled loop antenna of Reader and transponder form a transformer. The transponder can send data by load modulation, which is switching a load resistor or capacitor in the transponder with a subcarrier frequency. The ISO 14443 is a standard operating in proximity, where the

7、communicating distance is less than 10 cm. The sub-carrier frequency of ISO14443 is 847 KHz, and the bit rate of communication is 106Kbps. For ISO14443 type A, the transponder modulates data by Manchester coding. On the other hand, the subcarrier is BPSK modulated, for the ISO14443 type-B interface.

8、 The ISO15693 is a standard for vicinity cards, and ISO18000-3 is a standard for item management. The physical layer of air interface for ISO18000-3 Mode 1 is compatible with ISO15693. Recently chipsets for 13.56MHz multi-protocol reader are commercially available 6. However, for mobile and hand hel

9、d applications, system integration of 13.56MHz multi- protocol RFID reader with embedded antenna is strongly required. The goal of this work is to provide prototype of 13.56MHz multi-protocol RFID reader with embedded loop antenna. In this paper, 13.56MHz multi-protocol RFID reader SiP is designed a

10、nd implemented. All of the chips and passive components of RFID reader including HF loop antenna, are integrated into a single package. The paper is structured as follows, section II first describes the architecture of the proposed SiP reader, and then presents the configuration of 13.56MHz reader.

11、In session III, the design and implementation of the proposed reader is presented. After measurement results are demonstrated, discussion is presented in session IV, finally section V summarizes the paper. Item management, Access control, Supply Chain 1100 ASK 100% Modified Miller, 106kbit/s Load Mo

12、dulation Subcarrier fc/16 OOK Manchester, 106kbit/s 1100 ASK 10% NRZ-L, 106kbit/s 1100 Load Modulation Subcarrier fc/16 BPSK NRZ-L, 106kbit/s 9.44 us ASK 100% or 10% PPM, 1.65 or 26.48kbit/s 9.44 us 9.44 us 9.44 us 9.44 us 1100 Load Modulation Subcarrier fc/32 OOK Manchester, 6.62 or 26.48kbit/s 110

13、0 ISO14443 Type AISO14443 Type BISO15693 Reader to Tag Tag to Reader E- commerce, Credit cards, Access Control, Identification Applications Fig. 1 Application and key Protocols of the 13.56MHz RFID standards. II. ARCHITECTURE OF RFID READER SIP Fig.2 shows a block diagram of a typical 13.56MHz multi

14、- protocol RFID reader. Reader consists of digital part with interface controller and analogue part with TX, RX and reference voltage and clock generator. The function of the reader is controlled by MCU. External components for 13.56MHz reader are crystal oscillator and passive components for antenn

15、a matching. Antenna matching circuit consists of external components for a resonance circuit and a low pass filter 3-6. Interface Controller BUS MCU Digital PartAnalog Part ASK Modulator Antenna Driver Tx Demodulator RxLevel Shifter Voltage Reference/ Clock Generator Type Selector Filter / Amp / Com

16、parator Host Receiver Transmitter Antenna Matching Circuit Base Band Modem Digital Controller RFID Reader chipset Interface Controller BUS MCU Digital PartAnalog Part ASK Modulator Antenna Driver Tx Demodulator RxLevel Shifter Voltage Reference/ Clock Generator Type Selector Filter / Amp / Comparato

17、r Host Receiver Transmitter Antenna Matching Circuit Base Band Modem Digital Controller RFID Reader chipset Fig. 2 Block Diagram of Conventional HF RFID Reader 978-1-4244-2634-8/08/$25.00 2008 IEEE2008 Electrical Design of Advanced Packaging and Systems Symposium186 Fig. 3 Cross sectional view (a),

18、and floor plan (b) of the proposed 13.56MHz SiP RFID Reader. Fig.3 shows a floor plan and cross sectional view of the proposed SiP. MCU and Reader chips with passive matching components were integrated into a Package with chip-on- package technology. Wire bonding technology was used for chips on pac

19、kage integration. Embedded 8bit MCU is a controller for the reader. The embedded processor Manages commands and responses. Loop antenna is placed on the top of the package. The antenna and package substrate is connected through vertical via. We used a ferrite magnetic shielding layer between antenna

20、 and substrate. Table 1 summarize the design specification of the proposed reader SiP. TABLE I. DESIGN SPECIFICATIONS OF13.56MHZ SIP RFID READER ISO 14443 type A/ Type B, ISO 15693 Operating mode 10mA (normal)Typ. 25mA (Receive) Typ. 100mA (Transmit) Typ. 5mA (active) 150uA (Idle) 5uA (Power Down) P

21、ower consumption 4432 Pin Counts 12mm x 12mm (packaged) 2.64mm x 2.64mm (die) 7.0mm x 7.0mm (packaged) Die Size 13.56 MHz13.56 MHzFrequency 2.7 to 5.5 V2.7 to 3.3V (typ. 3.0 V)VDD Analog PartDigital Part 8-bit MCU (Atmel AT89C51ED2) 13.56MHz RFID Chip ISO 14443 type A/ Type B, ISO 15693 Operating mo

22、de 10mA (normal)Typ. 25mA (Receive) Typ. 100mA (Transmit) Typ. 5mA (active) 150uA (Idle) 5uA (Power Down) Power consumption 4432 Pin Counts 12mm x 12mm (packaged) 2.64mm x 2.64mm (die) 7.0mm x 7.0mm (packaged) Die Size 13.56 MHz13.56 MHzFrequency 2.7 to 5.5 V2.7 to 3.3V (typ. 3.0 V)VDD Analog PartDi

23、gital Part 8-bit MCU (Atmel AT89C51ED2) 13.56MHz RFID Chip III. DESIGN AND IMPLEMENTATION OF SIP A. Design and implementation of SiP Fig.4 shows layout design of the proposed SiP. In the floor plan, MCU and reader chip are place not to influence the TX switching noise into RX part. The power and gro

24、und lines of TX part and RX part of UHF reader is separated. We used 3 VDD lines for analog(AVDD), TX(TVDD) and digital(DVDD) part of the SiP. 2 chips with 40 passive components are integrated as shown in table 2. Four substrate layers with TOP/Ground/Power/Bottom are stacked. 136 balls are placed i

25、n the bottom layer, where we placed 44 balls for signal, 46 balls for Power, and 46 balls for Ground. Top Layer (1st)Bottom Layer (4th) Ground Layer (2nd)Power Layer (3th) Fig.4 Layout Design of the 4 layer of the Fabricated SiP RFID Reader. TABLE II. KEY SPECIFICATIONS OF FABRICATED SIP RFID READER

26、 Item Target Spec Package type CBGA Package size 30mmx30mm Chip stack 1 layer Package substrate layers 4 Package substrate stack Top/Ground/Power/Bottom Package pin out 136 balls Ball pitch/size 1mm/600um Substrate material LTCC # of dies 2 # of passives 40 Substrate thickness 200um # of decoupling

27、Cap 3 Line design rule 50um B. Simulation of proposed SiP Fig.5 shows simulated cross sectional view of the proposed SiP. Loop antenna with 6 turns on FR4 substrate is mounted on the metal plane with and without ferrite shielding layer. If the metal plane is near to the loop antenna the alternating

28、magnetic field generates eddy currents in the metal. These eddy currents cause loss and distortion of magnetic field. Solder pinSolder pinViaVia Reader chipMCU chip SMDSMD Solder maskSolder mask Wire bondsWire bonds Magnetic Shielding (Ferrite)Magnetic Shielding (Ferrite) AntennaAntenna Solder pinSo

29、lder pinViaVia Reader chipMCU chip SMDSMD Solder maskSolder mask Wire bondsWire bonds Magnetic Shielding (Ferrite)Magnetic Shielding (Ferrite) AntennaAntenna Reader ChipReader Chip SMD Passives SMD Passives MPU ChipMPU Chip AntennaAntenna 2008 Electrical Design of Advanced Packaging and Systems Symp

30、osium187 Therefore, it is necessary to shield the loop antenna with ferrite layer. Fig.6 shows structure of fabricated SiP reader. SiP Reader Antenna (6 turns)SiP Reader Antenna (6 turns) SiP Reader Antenna (6 turns) Metal Plate Ferrite film (0.3T, ur=15) Metal Plate x z y x z y x z y x z y (a) (b)

31、Fig.5 Simulated structure of the embedded antenna on the metal plane with and without ferrite magnetic shielding film. RFID SiP Board Ferrite shielding SiP Antenna + + + + Ferrite film (0.3T, ur=15) RFID SiP Board Ferrite shielding SiP Antenna + + + + Ferrite film (0.3T, ur=15) Fig.6 Structure of fa

32、bricated SiP Reader. We have simulated for following 3 cases, Antenna in free space and Antenna on a metal plane without/with ferrite shielding layer. Here, Ground plane and VDD lines of the SiP substrate is considered as metal plane in the simulation. The thickness of the ferrite film is 0.5mm with

33、 relative susceptibility of 15. The effects of Ferrite magnetic shielding layer on H-filed distribution was simulated by CST wave7. Fig 5(a) shows 3 dimensional field strength of the loop antenna in free space. The field is not disturbed and it is distributed symmetrical to z-axis. Fig 5(b) shows fi

34、eld distribution of the antenna on a metal plane. The magnetic field is disturbed due to an eddy current caused by metal plane. The field inside of the antenna loop is almost vanished. The disturbed field causes a reduction in field strength, and it is leading to decrease in operating distance. For

35、the antenna positioned on the ferrite film as shown in Fig 5(c), the disturbance of the magnetic field distribution is almost recovered. The simulation results show that the shielding of ferrite layer reduces an eddy current induced by the metal plane. The power integrity and signal integrity is sim

36、ulated by using AnSoft HFSS and AnSoft SI-Wave 8-9. The self impedance of 3 VDD lines, TVDD, AVDD and DVDD lines was simulated. Simulated self impedance of TVDD and AVDD lines without decoupling capacitor is ranged from about 40K ohm to 50 ohm for the simulated frequency range. (a) Antenna in free s

37、pace (b) Antenna on metal plane Metal plane (c) Antenna on ferrite + metal plane Fig.7 Simulated 3-Dimensional H-filed distribution by using CST wave7. TVDD AVDD DVDD TVDD AVDD DVDD (a)(b) 0.11.010100 Frequency (MHz) 105 104 103 102 10 Impedance ()Impedance () 1.00 0.10 0.01 0.00 0.11.010100 Frequen

38、cy (MHz) TVDD AVDD DVDD TVDD AVDD DVDD (a)(b) 0.11.010100 Frequency (MHz) 105 104 103 102 10 Impedance ()Impedance () 1.00 0.10 0.01 0.00 0.11.010100 Frequency (MHz) Fig.8 Power Integrity Simulation using SIwave(Ansoft), without decoupling capacitor(a), and with decoupling capacitor(b) 2008 Electric

39、al Design of Advanced Packaging and Systems Symposium188 With the decoupling capacitors, the simulated self impedances of the 3 VDD lines were suppressed smaller than 1 ohm, for the frequency ranged from 100K to 100MHz as shown in Fig 8(b). Fig 9 shows the Placement of decoupling capacitors. Fig.9 P

40、lacement of decoupling capacitors for the reduction of self- impedance. The effects of the compensation shown in Fig 8(b) was simulated by using Ansoft SIwave . IV. MEASURED RESULTS AND DISCUSSIONS Fig 10 shows top and bottom view of fabricated SiP Reader, and Fig 11 is a photograph of the fabricate

41、d RFID reader evaluation board. The reader has JTAG port for program downloading and debugging. The operation condition and tag IDs read from tags are displayed LCD. It also has UART serial interface for Host I/F, Commands and corresponding response from tags is monitored by PC using the host interf

42、ace. The RF signal was measured by oscilloscope. Fig. 12 is a measured antenna waveform when the reader is set to ISO 14443 type A and ISO 15693 mode. Measured operating distance was about 5cm. The power consumption is 100mA at 3.3V. Because of the page limitation of the submission format, the detai

43、ls of the measurement data can not be represented. More measured data will be presented at the conference. Fig.10 Top and bottom view of fabricated SiP Reader. V. CONCLUSIONS We have proposed a 13.56MHz multi-protocol SiP RFID reader having embedded antenna structures. The proposed SiP RFID reader h

44、as been designed to support protocols of ISO14443 A/B type, and ISO15693 standards. The operating mode is controlled by embedded MCU core, and the mode can be selected by users. The area of implemented SiP is 30mm 30mm with 4 metal layers. The operating distances are about. The implemented reader Si

45、P operates at single supply voltage of 3.3V. The current consumption is 200uA in idle mode and 100mA at active mode. Bulk cap Regulator 65mm 65mm RFID SiP without molding Fig.11 Fabricated RFID reader evaluation board. Fig.12 Measured results when reader setting of the 13.56MHz mode. ACKNOWLEDGMENT The authors thank to Jung-gun Byun, a