WG8 N 1673
Reasoning, Requirements and Definitions
Late DIN comment to FCD Ballot ISO/IEC 10373-6/FPDAM8
= WG8 N 1638 (SC17 N 3836)
Source: Infineon Technologies, NXP Semiconductors
Berlin, April 2010

 Reasoning
 Requirements
¬ Coupling factor
¬ Homogenous field area
 Definitions
¬ Calibration coil 2
¬ Test PCD antenna 2
¬ Test PCD antenna 2 tuning
¬ Test PCD assembly 2
 Conclusion
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 Definition of additional smaller antenna Classes requires extended operating field strength range.
¬ H max value up to 18 A/m (rms) to be generated by Test PCD assembly
 Power dissipation at Rext may get critical high!
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 Calculation:
¬ 18 A/m (rms) ->Simulation-> Iant = 3.75 A (rms)
¬ Power loss at:
– Rant = 1 Ohm: 14 W
– Rant = 4.7 Ohm: 66 W
20
20
18
16
14
12
H(d= 37.5 mm, r)
[A/m]
) 10
8
6
4
0
2
0
0
0
0.01
0.02
0.03
0.04
0.05
r [m] xA
0.06
0.07
0.08
0.09
0.1
0.1
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 Low Bit rate Test PCD Assembly
¬ Rant = 1 Ohm
¬ -> Change Power Range from 10 W to 15 W
 High Bit rate Test PCD Assembly
¬ Rant = 4.7 Ohm
¬ Cannot be used for Classes 4, 5, 6
¬ -> New smaller Test PCD assembly antenna required
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 Coupling factor between new small Test PCD antenna and PICC antenna of supported Classes shall be less than for current configuration.
 Coupling factor of current configuration
¬ PICC antenna coil = Reference PICC
¬ k = 5.5 %
¬ Target: k < 5.5 % for new assembly
10
9
8
7
6 k(d, r = 0)
[%]
, z0 2 ) 5
4
3
2
1
0
0 0.01
0.02
0.03
37.5
mm
0.04
0.05
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 Distance between new small Test PCD antenna and DUT shall be chosen in a way to maximize homogenous field area at DUT position.
¬ Target: Homogenous magnetic field with an area of Class 4.
 Definition of new smaller calibration coil for field strength determination with Class 4 area.
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 Coil characteristics
¬ The coil on the calibration coil card 2 shall have one turn. The outer size of the coil shall be 47 mm × 24 mm with corner radius
2 mm. Relative dimensional tolerance shall be ± 2 %.
– NOTE 1 The area over which the field is integrated is approximately 1100 mm 2
¬ The coil shall be made as a printed coil on printed circuit board
(PCB) plated with 35 μm copper. Track width shall be 500 μm with a relative tolerance of ± 20 %. The size of the connection pads shall be 1,5 mm × 1,5 mm.
– NOTE 2 At 13,56 MHz the approximate inductance is 140 nH and the approximate resistance is 0,3 Ω.
¬ The open circuit calibration factor for this coil is 0,118 V (rms) per A/m (rms) [Equivalent to 333 mV (peak-to-peak) per A/m
(rms)].
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 New Figure
ISO/IEC 7810 ID-1 outline
Coil 46 mm
×
24 mm
1 turn
Connections
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 The test PCD antenna 2 shall have a diameter of 100 mm and its construction shall conform to following drawings.
100 mm
Antenna coil
Ground compensation coil
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 New test PCD antenna 2 matching for Bit rates fc/128 to fc/16
 Same quality factor (Q ≈10) as with high Bit rate antenna, inductance approx. 300 nH.
50

power driver impedance matching network
Antenna coil
Z=50

C1b
C1a
C2 C3 C4
R ext
R ant
L ant
Value Unit
C1a 100 pF
Remarks
Voltage range 200 V
C1b
C2
4.7
270 pF pF
Voltage range 200 V
Voltage range 200 V
C3
C4
R ext
68
2-27
2,7 pF Voltage range 200 V pF Voltage range 200 V
Ω Power range 20 W
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 The sense coils and test PCD antenna shall be assembled parallel and with the sense and antenna coils coaxial and such that the distance between the active conductors is 23 mm as shown in following figure.
23 mm 23 mm
A ctive conductors
DUT
Calibration coil 2
Sense coil 2a Test PCD antenna Sense coil 2b
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 Area of homogenous field:
H(d, r)
H(d, 0) d = 37.5 mm, 150 mm antenna
H(d, r)
H(d, 0) d = 23 mm, 100 mm antenna
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r [m] r [m]
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 Coupling factor
¬ PICC antenna coil = Reference PICC 4 (Class 4) k(d, r = 0)
[%]
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-> k < 5.5 % achieved!
d [m]
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 Power losses of new small Test PCD assembly:
¬ 18 A/m (rms) ->Simulation-> Iant = 2.35 A (rms)
¬ Power loss at:
– Rant = 2.7 Ohm: 15 W -> o.k.
12
H(d= 23 mm, r)
[A/m]
) 10
8
6
4
2
0
0
20
18
16
14
0.02
0.04
0.06
0.08
0.1
¬ Small Test PCD assembly always with Sense coils 2
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¬ Use of Small Test PCD assembly for Class 4, Class 5 and Class 6
Page 15