Siksha Sarovar

Siksha Sarovar (sikshasarovar.com) is a free educational web application that helps students in India learn programming and prepare for academic and competitive exams. The platform offers structured coding courses (C, C++, Python, Java, HTML, CSS, PHP, Power BI, AI, Machine Learning, Data Science), complete university curriculum notes for BCA/MCA students with previous year question papers, Class 10 and Class 12 CBSE/HBSE school notes, and dedicated preparation material for SSC, UPSC, Banking, Railway and other government exams. Browsing the site is completely free and requires no account. Users may optionally sign in with Google solely to save their learning progress, quiz scores and personal preferences across devices.

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Siksha Sarovar is a free e-learning platform for coding courses, BCA university notes and competitive exam preparation. Optional Google sign-in saves your learning progress across devices.

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2.3 RFID Technology: Theory, Anatomy and Frequencies

Lesson 9 of 31 in the free Internet of Things (IoT) notes on Siksha Sarovar, written by Rohit Jangra.

2.3.1 RFID Architectural View

Radio Frequency Identification (RFID) uses electromagnetic fields to automatically identify and track tags. Unlike barcodes, it does not require line-of-sight and can read hundreds of tags simultaneously.

  1. The Tag (Transponder): Consists of a microchip (storage) and an antenna (coupling).
  2. The Reader (Interrogator): Emits radio waves and receives signals back from the tags.
  3. Middleware: A software layer that processes the EPC (Electronic Product Code) and updates the database.

2.3.2 Frequency Bands: A Comparative Technical Study

Band NameFrequency RangeTypical RangeRead SpeedInterference ToleranceUse Case
LF (Low)125 - 134 kHz10 cmSlowHigh (Works near metal/water)Livestock tracking
HF (High)13.56 MHz1 mMediumModerateNFC, Smart Cards
UHF (Ultra)860 - 960 MHz12 mVery HighLow (Fails near metal)Supply Chain, Tolls
MW (Micro)2.45 GHz100 mUltra HighLowReal-time tracking

2.3.3 Passive vs Active vs Semi-Passive Tags

  • Passive Tags: No internal battery. Powered by the reader's magnetic field via Inductive Coupling. Lifespan: Virtually infinite.
  • Active Tags: Have an internal battery. Constants broadcasts ID autonomously. Range up to 100m.
  • Semi-Passive: Battery powers the chip, but communication is powered by the reader's field.

2.3.4 Security and Privacy in RFID

  • Kill Commands: A feature to permanently disable a tag after sale.
  • Eavesdropping: Malicious reader sniffing tag data from a distance.
  • Relay Attacks: Intercepting a tag signal and replaying it to a remote reader.