M211_50-Ohm-Ant_V11_RBt -1 Philips Semiconductors 50 Ohm matched antenna Proximity Antenna Training for MHz

M211_50-Ohm-Ant_V11_RBt -2 Philips Semiconductors 50  matched antenna RC500 RC400 (or other Reader) EMC- Filter Rx Tx Rx- Circuit Matching Z=50  Antenna Matching Z = 50  50  matched antenna

M211_50-Ohm-Ant_V11_RBt -3 Philips Semiconductors 50  matched antenna 3) Tuning 5) Finetuning 1) Matching 6) Receive Circuit Requirements: load impedance = 50  ! 1) Matching 2) Resonance resonance at MHz 2) Resonance 4) Q-factor quality factor < 35 quality factor < 100 4) Q-factor

M211_50-Ohm-Ant_V11_RBt -4 Philips Semiconductors 6) Receive Circuit 2) Resonance 3) Tuning 4) Q-factor 5) Finetuning 1) Matching 50  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) Tuning 4) Q-factor 5) Finetuning 6) Receive Circuit

M211_50-Ohm-Ant_V11_RBt -5 Philips Semiconductors 50  matched antenna Design a coil L R ext R MHz! L and R of the antenna coil shall be measured at MHz (impedance analyser or L-C-R Meter). L a+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 conductor N: number of turns  : shape factor  =1.07 for circular coils  =1.54 for square coils Estimation:

M211_50-Ohm-Ant_V11_RBt -6 Philips Semiconductors 50  matched antenna Design a coil L R ext R coil

M211_50-Ohm-Ant_V11_RBt -7 Philips Semiconductors 50  matched antenna Calculate the parallel capacitance Consider the power consumption! with C2C2 L R coil C1C1 Z ant R ext

M211_50-Ohm-Ant_V11_RBt -8 Philips Semiconductors 50  matched antenna Tune resonance and impedance Start tune phase to 0° ± 10° with C2 possible ? Z < Z ant -10%? Z >Z ant +10% ? f res >13.56MHz ? increase C2 decrease C2 increase C1 decrease C1 Tuning OK |Z|=Z ant ± 10% phase=0° ± 10° yes no

M211_50-Ohm-Ant_V11_RBt -9 Philips Semiconductors 50  matched antenna Tune resonance and impedance

M211_50-Ohm-Ant_V11_RBt -10 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  matched antenna Connect Antenna to the MF RC500 Guideline:

M211_50-Ohm-Ant_V11_RBt -11 Philips Semiconductors 50  matched antenna Tune resonance and impedance distance increased ? no  C is added Find max. distance yes no Add  C  C < 10 pF Start decrease C2 remove  C add 2*  C to C2a add 2*  C to C2b no Find d max C2C2 L ant R ant C1C1 Z ant R ext

M211_50-Ohm-Ant_V11_RBt -12 Philips Semiconductors A Channel A: 500mV/DIV Timebase: 1µs/DIV PHILIPS Reader 2.5µs 95% send request command 50  matched antenna Checking the Q-Factor

M211_50-Ohm-Ant_V11_RBt -13 Philips Semiconductors 50  matched antenna Checking the Q-Factor Manchester Decoder Serial Data IN Carrier Demodulator Rx Subcarrier Demodulator Serial Data OUT Miller Coder Envelope Modulator Driver Tx Digital Test Signal Modulator Source Switch MFout Select Switch Subcarrier Demodulator RFU 0 1 Mfin / PIN3 Mfout / PIN4 Manchester w. Subcarrier Transmit NRZ Envelope Decoder Source Switch Manchester OUT

M211_50-Ohm-Ant_V11_RBt -14 Philips Semiconductors 50  matched antenna Checking the Q-Factor time in msec Pin 4 (3): Transmit NRZ 2V/Dev. Pin 4 (2): Envelope 2V/Dev. RFOut 0.5V/Div. RC500 test signals

M211_50-Ohm-Ant_V11_RBt -15 Philips Semiconductors 50  matched antenna Check 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 Guideline:

M211_50-Ohm-Ant_V11_RBt -16 Philips Semiconductors 50  matched antenna Check the cards answer Reader send request command Startvalue: Insert RX-Circuitry Check the card’s answer with oscilloscope (trigger on Pin 4, Envelope) Get the max. operating distance Check the received signal at the RC500 (Pin 4, Manchester) Adjust R1 (valid Manchester at min. and max operating distance) “Antenna-Loop” Attention: Input voltage at Pin 29 (Rx) shall not exceed ± 1.5V!

M211_50-Ohm-Ant_V11_RBt -17 Philips Semiconductors time in msec Pin 4 (5): Manchester 2V/Dev. Pin 4 (4): Manchester with Subcarrier 2V/Dev. RFOut 1V/Dev. 50  matched antenna Checking the Q-Factor RC500 test signals

M211_50-Ohm-Ant_V11_RBt -18 Philips Semiconductors 6) Receive Circuit 2) Resonance 3) Tuning 4) Q-factor 5) Finetuning 1) Matching Design a coil Calculate the parallel capacitance Tune resonance and impedance Connect antenna to the RC500 Tune resonance and impedance Check (and adjust) the Q-factor Finetune resonance and impedance Find the values for Rx-circuit 3) Tuning 4) Q-factor 5) Finetuning 6) Receive Circuit 50  matched antenna Summary

M211_50-Ohm-Ant_V11_RBt -19 Philips Semiconductors 50  matched antenna Balun I I +U -U 50  Balun (balanced - unbalanced) The same as directly matched antenna...

M211_50-Ohm-Ant_V11_RBt -20 Philips Semiconductors I I 50  matched antenna Compensated antenna I I 50 

M211_50-Ohm-Ant_V11_RBt -21 Philips Semiconductors 50  matched antenna Principle of the compensated antenna without compensation with compensation

M211_50-Ohm-Ant_V11_RBt -22 Philips Semiconductors L = 450nH R = 0.3  50  matched antenna Example: Circular antenna

M211_50-Ohm-Ant_V11_RBt -23 Philips Semiconductors L = 700nH R = 0.3  50  matched antenna Example: Square antenna