Cheat Sheet – RFID Solution Design

Know the components of an RFID system
Know what are the configuration factors that impact overall system effectiveness

Download the Cheat Sheet in PDF

A Reader – fixed, handheld, sled, embedded, module
A Cable – various lengths and thicknesses
Connectors – cable connectors to reader and antenna, power connectors, network connectors
An Antenna
- Circular polarization
- Linear polarization
A Hub or a multiplexer (not always present) – allows to connect more antennas to a reader than there are available ports.
Peripherals (not always present) – RFID printer/encoder, barcode scanner, lights, sensors

Reader port impedance – must match the antenna impedance (loss resistance, voltage to current, standard is 50 ohm, tuned at manufacturing) for proper performance and to avoid component damage.
Antenna should have minimum VSWR (voltage standing wave ratio/return loss) for best impedance and most efficient operation.
Antenna polarization
- Circular polarization – shorter read range, but orientation insensitivity
- Linear polarization – longer read range, more focused, orientation sensitive
Antenna gain
- The higher the gain, the narrower the beam but the longer read range.
- The lower the gain, the wider the beam but the shorter the read range.
- Gain together with reader power output have to produce certain total transmitted power that complies with regulations.
Cable connector type/materials
Cable type & signal loss – The thicker the cable, the lower the loss, the more expensive the cable.
Cable length – The longer the cable, the higher the loss, the worse system performance

Tag antenna size and type – the larger the antenna, the more power it can harvest from reader signal, the longer the read range. But may not be practical for small items.
- Single dipole tag antenna – may be orientation sensitive with linearly polarized reader antennas
- Dual dipole tag antenna – less orientation sensitive
Material tag is placed on or near
- Water, moist materials, aqueous liquids – can detune the tag, must tune specifically and create offset from the surface
- Metal – detunes the tag, must tune specifically and create offset
Tag processor type (“chip”) – chips differ by manufacturer, by processing speed, sensitivity, memory size and attachment to the antenna.
Tag antenna impedance has to match the impedance of the integrated circuit (IC) over a desired bandwidth for best performance. It is tuned at manufacturing.

What is required is knowledge of what factors must be taken into account in configuring a RFID system rather than detailed knowledge of how to do so