RFID Technology
The engineering layer: UHF physics, chip and antenna design, tag construction, encoding, read-range budgets and the failure modes that show up only in the field. Written for people who specify hardware rather than browse catalogues.
Articles in this topic
RFID ROI: A Model You Can Defend, Not a Number You Can Sell
Most RFID business cases fail not because the technology is wrong but because the benefit lines are unmeasurable. Build the model from the audit trail backwards.
Tag Failure Analysis: The Read Rate You Measure Is Not the Reliability You Need
Most tag programmes die in the field, not in the lab. The difference between a 99 percent demo and a 97 percent deployment is a failure analysis discipline nobody budgets for.
RFID, BLE and UWB: Fuse the Decisions, Not the Sensors
Zone-level RFID, coarse BLE and centimetre UWB sound complementary, and they are. The integration only works if fusion happens at the decision layer rather than in a blender of raw coordinates.
RFID Security and EPC Passwords: What Gen2 Actually Protects
Gen2 passwords protect the tag from being rewritten or killed. They do not hide the EPC, and they do not stop a cloner. Security starts with knowing which of those you need.
EPC Checksums and Read-Back: Proving a Tag Holds What You Wrote
A write command that returns success proves almost nothing. Verification means reading the bank back, checking the CRC and the value separately, and knowing which tag you actually wrote to.
RFID Reader Power and Region Settings: Compliance Is a Configuration Problem
A reader that ships compliant becomes non-compliant the moment someone raises the power or selects the wrong region. Treat radio settings as controlled configuration, not as a field tuning knob.
Substrate and Dielectric Constant: Why the Same Tag Reads Differently on Glass, Plastic and Liquid
A label qualified on cardboard can lose most of its range on a glass shelf of syrup bottles. The cause is not the chip but the permittivity of whatever sits under the antenna, and it is predictable if you measure instead of guess.
UHF and NFC in the Same Building: Coexistence Without Compromise
UHF reads a pallet from four metres; NFC reads a phone from four centimetres. They occupy different bands, serve different moments and fail in different ways. The deployment problem is not interference — it is keeping two identities, two data paths and two support models from drifting apart.
Antenna Polarization: The 3 dB You Cannot See
Circular polarization costs 3 dB and buys orientation tolerance. Linear polarization does the opposite. Most read-zone problems are not power problems at all; they are a mismatch between the antenna's polarization and the way the tag is actually lying on the product.
Chipless RFID: The Promise and the Physics
A chipless tag costs a few cents and carries a fixed code with no memory, no sensor and no kill command. That trade-off opens logistics, tickets and consumables — and closes security, rewritable data and anything that needs a unique serial number over time.
Dense Reader Deployment: Engineering the Interference Away
When ten readers share one aisle, read rates fall for reasons that have nothing to do with tag quality. Dense Reader Mode, channel plans, antenna geometry and duty cycle are four separate levers, and pulling only one of them rarely fixes anything.
RFID Printer Consumables: Matching Ribbon, Label and Printhead
Most RFID print failures are blamed on the printer and caused by a three-way mismatch between ribbon, face stock and the inlay hidden underneath. Here is how to qualify a consumable set before it reaches a production line.
RFID on Android Handhelds: What the SDK Does Not Tell You
A handheld RFID app is a background-service problem wearing a scanner costume. Reader threads, trigger semantics, bulk-read interfaces that operators can actually use, offline queues and battery budgets — the engineering that separates a demo from a shift-proof tool.
LLRP in Practice: The Protocol Is Simple, the Configuration Model Is Not
LLRP looks intimidating because of its binary TLV encoding, but the working set is small: five configuration messages, one ROSpec, one AccessSpec and a report selector. A practical map of the protocol, the fields that change behaviour, and the status codes worth handling.
Anti-Metal RFID Tags: Ferrite Is Not Magic, It Is Impedance Engineering
A standard inlay on a steel plate reads at zero centimetres. Ferrite backing restores a usable link by changing the boundary conditions, not by adding power. The electromagnetics, the spacer thickness that matters, a selection matrix by metal geometry, and the cases where no tag will save you.
EPC Gen2 encoding: TID, EPC and user memory explained properly
What each Gen2 memory bank is for, how to choose EPC schemes that survive operations, and the encoding mistakes that cause duplicate or unreadable tags.
UHF RFID Antenna Gain and Beamwidth: The Zone Is the Specification
Gain concentrates energy, it does not create it. A practical framework for choosing six, eight or twelve dBi antennas: the arithmetic of range, why beamwidth decides layout, circular versus linear polarisation, mounting height and tilt, and the problems gain cannot fix.
Circular vs Linear Polarization: The RFID Antenna Choice That Shapes the Read Zone
Circular antennas forgive tag orientation and lose 3 dB; linear antennas gain range and create blind spots. Here is how polarization decides which one belongs on a portal, a conveyor, a shelf or a handheld.
RFID Chip Miniaturization: Why One Millimetre Changes the Product
The bare die has moved from roughly 0.4 square millimetres to about 0.18, and the packaged part from 3 mm to 2 mm. That is not just a process story: it is why jewellery, medical devices and embedded assets became addressable, and why antenna design is now harder than the chip.
RFID Tag Memory: What Each Bank Is For, and What to Put in It
A Gen2 tag has four memory banks and each one has a different contract: EPC is business data, TID is the manufacturer's fingerprint, User is yours, Reserved holds the kill and access passwords. Getting the split right prevents most encoding and lockout problems.
Impinj R2000 vs E710: Two Chips, Two Different Reader Classes
R2000 and E710 are not successive generations of one product; they are answers to different reader classes. A comparison of architecture, receiver sensitivity, antenna ports, power, thermal budget and where each chip belongs.
LLRP in Practice: Configuring RFID Readers Without Creating New Silos
LLRP gives you one protocol for multi-vendor readers and nothing more. Configuration, filtering, deduplication and store-and-forward still belong in middleware — here is how to structure them.
Reader Power vs Read Range: Where the Decibels Actually Go
Turning up reader power feels like it should extend the read zone. In a passive UHF system the relationship is logarithmic, legally capped, and often limited by the tag's wake-up threshold rather than the reader. Here is the real arithmetic.
The Battery-Free Frontier: What Harvesting and Backscatter Can Really Do
Passive tags already steal power from the reader. The research frontier removes the reader as well, harvesting ambient light, motion and stray RF. A grounded look at link budgets, data rates and the system conditions under which battery-free sensing is actually usable.
RFID Tag Antenna Design: Why the Antenna, Not the Chip, Sets Performance
A passive UHF inlay is an antenna problem before it is a silicon problem. This covers conjugate matching to a chip at 12-j140 ohms, dipole versus patch trade-offs, broadband designs for 860–960 MHz, and what the object behind the tag does to all of it.
Passive Sensing Tags: Measuring Temperature, Humidity and Vibration Without a Battery
A passive sensing tag still carries an EPC, but the data that matters is what happened to the object between two reads. How backscatter sensors actually work, where accuracy comes from, and the read-point design that decides whether you get a measurement or a guess.
UHF RFID Deep Dive: From Reader Carrier to ERP Record
What actually happens in a UHF RFID read cycle, where the power goes in the link budget, how Gen2 arbitrates hundreds of tags, and which physical limits decide whether your deployment reaches 99 % or stalls at 90 %.