RFID - Elektor.pt

Contents2.1.4 Part 4: communication protocol ...................... 492.1.4.1 Protocol activation ......................... 492.1.4.2 T=CL protocol block structure. ................ 562.1.5 Information Block (I Block) ......................... 562.1.5.1 Receive-ready Blocks (R Blocks) ............... 582.1.5.2 Supervisory Blocks (S Blocks) ................ 592.1.6 Electromagnetic disturbance (EMD) ................... 612.1.6.1 Rest period .............................. 622.1.6.2 Rest level ................................ 632.1.6.3 Distinction between invalid cardresponse and EMD ........................ 632.1.6.4 The MFRC522 reader IC and EMD ............... 632.2 ISO/IEC 10373-6 test methods. ........................... 642.2.1 Test equipment ................................. 652.2.1.1 Calibration coil ........................... 652.2.1.2 Test PCD assembly ........................ 652.2.1.3 ReferencePICC ........................... 662.2.2 Tuning and calibration ............................ 682.2.2.1 Tuning ................................. 682.2.2.2 Calibration .............................. 682.2.3 Measurements at the reader ........................ 692.2.3.1 Range measurement ....................... 692.2.3.2 Measurement effort ........................ 692.2.4 Tests for Layer 3 and 4 ............................ 702.3 Near Field Communication (NFC) .......................... 702.3.1 Introduction ................................... 702.3.2 NFC air interface ................................ 712.3.2.1 NFC device as card ........................ 712.3.2.2 NFC device as a reader ..................... 712.3.2.3 NFC device in ‘active’ mode .................. 72copyright Elektor3 RFID Antenna Design ..................................... 733.1 Theoretical Fundamentals ............................... 733.1.1 Antenna as Resonant Circuit ........................ 733.1.2 Transformer Model ............................... 773.1.3 The Biot-Savart Law .............................. 793.1.4 Optimal Antenna Size ............................. 803.2 Reader Antennas ..................................... 833.2.1 Antenna Quality ................................. 833.2.1.1 Data Transmission Bandwidth ................. 833.2.1.2 Stability Against Detuning ................... 863.2.2 Electrically Conductive Surfaces in the Vicinityof the Antenna ................................... 893.2.2.1 Ferrites ................................ 903.2.3 Balanced and Unbalanced Antennas ................... 923.2.3.1 Balanced Antenna ......................... 933.2.3.2 Unbalanced Antenna ....................... 964