HFSS Application RFID - Ansys
HFSS Application RFID - Ansys
HFSS Application RFID - Ansys
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<strong>HFSS</strong> <strong>Application</strong><br />
<strong>RFID</strong> (Radio Frequency<br />
Identification)<br />
ANSYS, Inc. Proprietary<br />
© 2009 ANSYS, Inc. All rights reserved.<br />
1-1<br />
February 23, 2009<br />
Inventory #002593
What is <strong>RFID</strong>?<br />
• Wireless identification<br />
– Reader Antenna communicates with Tags<br />
• <strong>Application</strong>s<br />
– Inventory<br />
– Vehicle Tracking<br />
–Pets<br />
–Tolls<br />
Reader Tag<br />
© 2009 ANSYS, Inc. All rights reserved. ANSYS, Inc. Proprietary
What is <strong>RFID</strong>?<br />
• Frequencies of operation<br />
– Low Frequency<br />
• 125 kHz<br />
• 13.56 MHz (near field coupling)<br />
• Mass production<br />
• Low Cost<br />
• Short range usually less than 1 meter<br />
– UHF<br />
• 433 MHz<br />
• 868 MHz<br />
• 915 MHz<br />
• 2.45 GHz (far field operation)<br />
• Larger range usually only used on high cost items<br />
© 2009 ANSYS, Inc. All rights reserved. ANSYS, Inc. Proprietary
<strong>RFID</strong> Antenna and System Design<br />
• <strong>HFSS</strong> <strong>Application</strong><br />
– Reader antenna<br />
– Tag<br />
– Whole transmission setup<br />
• Types of <strong>RFID</strong> Tags<br />
– Active<br />
• Internal power source<br />
– Passive<br />
• No internal power source<br />
http://www.openpcd.org/<br />
Typical Tag Antenna<br />
used by the world’s<br />
largest retailer<br />
© 2009 ANSYS, Inc. All rights reserved. ANSYS, Inc. Proprietary
Estimation of Transmission Distance<br />
Friis Equation<br />
• Analytical approaches assume<br />
– Non-disturbed near field conditions<br />
• No proximity of dielectric and metal objects<br />
– Known antenna characteristics<br />
– No diffraction and reflection effects<br />
– This is not the case in most real <strong>RFID</strong> situations<br />
• Full system simulation including reader, tags and environment<br />
is necessary<br />
TRANSMIT ANTENNA<br />
GAIN* = G T<br />
Polarization = ρ T<br />
REFL. COEFF = Γ T<br />
P<br />
P<br />
DISTANCE = R<br />
WAVELENGTH OF SIGNAL = λ<br />
2<br />
R ⎛ λ ⎞<br />
⎜ ⎟ GTG<br />
R<br />
T ⎝ 4πR<br />
⎠<br />
= ˆ ρ • ˆ ρ<br />
( )( )<br />
2 2<br />
1−<br />
Γ 1−<br />
Γ<br />
RECEIVE ANTENNA<br />
GAIN* = G R<br />
Polarization = ρ R<br />
REFL. COEFF = Γ R<br />
© 2009 ANSYS, Inc. All rights reserved. ANSYS, Inc. Proprietary<br />
T<br />
R<br />
2<br />
T<br />
R
UHF <strong>RFID</strong> Transmission System<br />
• <strong>RFID</strong> System<br />
– Wall-mounted 915 MHz reader antenna and pallet with 12<br />
transponder antennas at approximately 2.20 meters away simulated<br />
in <strong>HFSS</strong> v12<br />
– 14 Ports<br />
– Frequency range from 800 MHz to 1GHz<br />
Reader Antenna (with<br />
two polarization setups)<br />
Pallet with 12 PS-foam boxes<br />
and 12 <strong>RFID</strong> tags<br />
Two Tags<br />
© 2009 ANSYS, Inc. All rights reserved. ANSYS, Inc. Proprietary
UHF <strong>RFID</strong> Transmission System<br />
• Reader Excitations<br />
Port 2<br />
– Two Wave Ports<br />
• Circular Polarization<br />
– Allows stable delivery of energy in a radial symmetrical pattern<br />
so <strong>RFID</strong> tags can be read regardless of orientation<br />
Port 1<br />
© 2009 ANSYS, Inc. All rights reserved. ANSYS, Inc. Proprietary
UHF <strong>RFID</strong> Transmission System<br />
• Results<br />
– Mag E<br />
© 2009 ANSYS, Inc. All rights reserved. ANSYS, Inc. Proprietary
UHF <strong>RFID</strong> Transmission System<br />
• Results<br />
– Cmplx Mag JSurf<br />
© 2009 ANSYS, Inc. All rights reserved. ANSYS, Inc. Proprietary
UHF <strong>RFID</strong> Transmission System<br />
• Results<br />
Ansoft LLC XY Plot 1<br />
completemodel3<br />
Y1<br />
0.00<br />
-5.00<br />
-10.00<br />
-15.00<br />
-20.00<br />
-25.00<br />
-30.00<br />
Curve Info<br />
dB(S(WavePort1,WavePort1))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,WavePort2))<br />
Setup1 : Sweep2<br />
0.80 0.83 0.85 0.88 0.90 0.93 0.95 0.98 1.00<br />
Freq [GHz]<br />
© 2009 ANSYS, Inc. All rights reserved. ANSYS, Inc. Proprietary
UHF <strong>RFID</strong> Results<br />
Y1<br />
-60.00<br />
-80.00<br />
-100.00<br />
-120.00<br />
• Transmission losses between reader antenna and<br />
transponders tags (S-parameters)<br />
Ansoft LLC<br />
0.00<br />
Port1<br />
completemodel3<br />
Curve Info<br />
dB(S(WavePort1,LumpPort1))<br />
Setup1 : Sweep2<br />
dB(S(WavePort1,LumpPort2))<br />
Setup1 : Sweep2<br />
dB(S(WavePort1,LumpPort3))<br />
Setup1 : Sweep2<br />
dB(S(WavePort1,LumpPort4))<br />
-20.00<br />
Setup1 : Sweep2<br />
dB(S(WavePort1,LumpPort5))<br />
Setup1 : Sweep2<br />
dB(S(WavePort1,LumpPort6))<br />
Setup1 : Sweep2<br />
dB(S(WavePort1,LumpPort7))<br />
Setup1 : Sweep2<br />
dB(S(WavePort1,LumpPort8))<br />
Setup1 : Sweep2<br />
Ansoft LLC<br />
-40.00<br />
Port2<br />
completemodel3<br />
-40.00<br />
dB(S(WavePort1,LumpPort9))<br />
Setup1 : Sweep2<br />
dB(S(WavePort1,LumpPort10))<br />
Setup1 : Sweep2<br />
dB(S(WavePort1,LumpPort11))<br />
Setup1 : Sweep2<br />
dB(S(WavePort1,LumpPort12))<br />
Setup1 : Sweep2<br />
-45.00<br />
0.80 0.83 0.85 0.88 0.90 0.93 0.95 0.98 1.00<br />
Freq [GHz]<br />
0.85 0.88 0.90 0.92 0.95 0.97 1.00<br />
Freq [GHz]<br />
© 2009 ANSYS, Inc. All rights reserved. ANSYS, Inc. Proprietary<br />
Y1<br />
-50.00<br />
-55.00<br />
-60.00<br />
-65.00<br />
-70.00<br />
-75.00<br />
-80.00<br />
Curve Info<br />
dB(S(WavePort2,LumpPort1))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,LumpPort2))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,LumpPort3))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,LumpPort4))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,LumpPort5))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,LumpPort6))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,LumpPort7))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,LumpPort8))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,LumpPort9))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,LumpPort10))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,LumpPort11))<br />
Setup1 : Sweep2<br />
dB(S(WavePort2,LumpPort12))<br />
Setup1 : Sweep2
UHF <strong>RFID</strong> System<br />
• Parametric change of geometry in the vicinity of the tagantennas<br />
© 2009 ANSYS, Inc. All rights reserved. ANSYS, Inc. Proprietary
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