M211_50-Ohm-Ant_V11_RBt -1 Philips Semiconductors 50 Ohm matched antenna Proximity Antenna Training...
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Transcript of M211_50-Ohm-Ant_V11_RBt -1 Philips Semiconductors 50 Ohm matched antenna Proximity Antenna Training...
M21
1_50
-Ohm
-Ant
_V11
_RB
t -1
Philips Semiconductors
50 Ohm matched 50 Ohm matched antennaantenna
Proximity Antenna Training for 13.56 MHzProximity Antenna Training for 13.56 MHz
M21
1_50
-Ohm
-Ant
_V11
_RB
t -2
Philips Semiconductors
50 50 matched antenna matched antenna
RC500RC400
(or other
Reader)EMC-Filter
Rx
Tx
Rx- Circuit
Mat
chin
gZ
=50
Antenna
Matching
Z =
50
50 matched antenna
M21
1_50
-Ohm
-Ant
_V11
_RB
t -3
Philips Semiconductors
50 50 matched antenna matched antenna
3) Tuning
5) Finetuning
1) Matching
6) Receive Circuit
Requirements:
load impedance = 50!
1) Matching
2) Resonanceresonance at 13.56 MHz
2) Resonance
4) Q-factor quality factor < 35
quality factor < 100
4) Q-factor
M21
1_50
-Ohm
-Ant
_V11
_RB
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Philips Semiconductors
6) Receive Circuit
2) Resonance3) Tuning4) Q-factor5) Finetuning
1) Matching
50 50 matched antenna matched antenna
Guideline:
• Design a coil
• Calculate the parallel capacitance
• Tune resonance and impedance
•Connect antenna to the RC500•Tune again
• Check (and adjust) the Q-factor
• Finetune resonance and impedance
• Find the values for Rx-circuit
3) Tuning4) Q-factor5) Finetuning
6) Receive Circuit
M21
1_50
-Ohm
-Ant
_V11
_RB
t -5
Philips Semiconductors
50 50 matched antenna matched antennaDesign a coilDesign a coil
L
Rext
Rcoil
HnHLL ba 2...300 HnHLL ba 2...300
2...2.0coilR 2...2.0coilR @13.56 MHz!
L and R of the antenna coil shall be measured at 13.56 MHz (impedance analyser or L-C-R Meter).
8.1)/ln(][
][2.0 NDll
m
HL ba
8.1)/ln(
][
][2.0 NDll
m
HL ba
La+b = L: coil inductance
l: length of the conductor circular: l = 2**r (r=coil radius) square l = 4*a (a lateral length) d: diameter of the conductorN: number of turns: shape factor =1.07 for circular coils =1.54 for square coils
Estimation:
M21
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-Ohm
-Ant
_V11
_RB
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Philips Semiconductors
50 50 matched antenna matched antennaDesign a coilDesign a coil
0 5 10 15 20
0.5
1
1.5
0 5 10 15 20
1
2
antenna radius [cm]
antenna radius [cm]
L [µH]
N
L
Rext
Rcoil
M21
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-Ohm
-Ant
_V11
_RB
t -7
Philips Semiconductors
50 50 matched antenna matched antennaCalculate the parallel capacitanceCalculate the parallel capacitance
CoilLext RQ
LRRR
CoilLext R
Q
LRRR
Consider the power consumption!
2
2
22
2
2
2
1
1
1
CR
LCCL
CLRC
2
2
22
2
2
2
1
1
1
CR
LCCL
CLRC
aaa ZRL
ZRLR
ZRL
C
111
1
222
22
aaa ZRL
ZRLR
ZRL
C
111
1
222
22
50Anta ZZwith
C2
L
Rcoil
C1
Zant
Rext
M21
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-Ohm
-Ant
_V11
_RB
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Philips Semiconductors
50 50 matched antenna matched antennaTune resonance and impedanceTune resonance and impedance
Start
tune phase to 0° ± 10° with C2
possible ?
Z < Zant-10%?
Z >Zant+10% ?
fres>13.56MHz ?increase
C2
decreaseC2
increase C1
decrease C1
Tuning OK|Z|=Zant ± 10%
phase=0° ± 10°
yes
yes
yes
yes
no
no
no
no
0050 jant eZ
0050 jant eZ
M21
1_50
-Ohm
-Ant
_V11
_RB
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Philips Semiconductors
50 50 matched antenna matched antennaTune resonance and impedanceTune resonance and impedance
10 11 12 13 14 15 16 17 18 -100
-80
-60
-40
-20
0
20
40
60
80
0
200
400
600
800
1000
1200
1400
1600
180013.56 MHz
f [MHz]
|Zin| [] phase [deg.]
Zant
phase
M21
1_50
-Ohm
-Ant
_V11
_RB
t -1
0
Philips Semiconductors
• Design a coil
• Calculate the parallel capacitance
• Tune resonance and impedance
•Connect antenna to the RC500•Tune again
• Check (and adjust) the Q-factor
• Finetune resonance and impedance
• Find the values for Rx-circuit
50 50 matched antenna matched antennaConnect Antenna to the MF RC500Connect Antenna to the MF RC500
Guideline:
M21
1_50
-Ohm
-Ant
_V11
_RB
t -1
1
Philips Semiconductors
50 50 matched antenna matched antennaTune resonance and impedanceTune resonance and impedance
distance increased ?
no Cis added
Find max. distance
yes
yes
no
Add C C < 10 pF
Start
decrease C2
remove C add 2* C to C2aadd 2* C to C2b
no
Find dmax
C2
Lant
Rant
C1
Zant
Rext
M21
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-Ohm
-Ant
_V11
_RB
t -1
9
Philips Semiconductors
50 50 matched antenna matched antennaBalunBalun
I
I
+U
-U
50
Balun (balanced - unbalanced)Balun (balanced - unbalanced)
The same as directly matched antenna...
M21
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-Ohm
-Ant
_V11
_RB
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0
Philips Semiconductors
I
I
50 50 matched antenna matched antennaCompensated antennaCompensated antenna
I
I
50 50
M21
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-Ohm
-Ant
_V11
_RB
t -2
1
Philips Semiconductors
50 50 matched antenna matched antennaPrinciple of the compensated antennaPrinciple of the compensated antenna
without compensation
with compensation
M21
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-Ohm
-Ant
_V11
_RB
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2
Philips Semiconductors
L = 450nHR = 0.3
50 50 matched antenna matched antennaExample: Circular antennaExample: Circular antenna
M21
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-Ohm
-Ant
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_RB
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3
Philips Semiconductors
L = 700nHR = 0.3
50 50 matched antenna matched antennaExample: Square antennaExample: Square antenna