Long-Range UHF RFID Readers with Integrated 7–12 dBi Antenna

Start from the distance between the reader and the tag, then pick the lowest antenna gain that covers it. Extra gain adds reach along the beam, so an oversized reader is more likely to pick up tags beyond the intended zone, such as parked vehicles or passing traffic. Higher gain also narrows the beam, which helps when a neighboring lane sits to the side.

Range figures depend on the tag, what it is mounted on and the site. Beyond distance, check three more points:

• Output: Wiegand if an existing controller makes the access decision; RS232, RS485, USB or TCP/IP if your software does.
• Band: order 902–928 MHz or 865–868 MHz to match your country. Other bands are available on request.
• Mounting and climate: panel size, pole diameter and operating temperature. The U630-M is rated from -40 °C; state low-temperature needs for other models in your RFQ.

Wiegand 26/34 sends the tag number one way, from reader to controller. It is the simplest way to add UHF to an existing parking or access control system. A Wiegand 26 frame carries 24 data bits and Wiegand 34 carries 32, so the controller receives only part of a 96-bit EPC. Agree which number the controller expects before you issue tags.

RS232 suits a short cable to a PC. RS485 is the usual choice when the PC is far from the gate. USB is handy for set-up and bench tests. TCP/IP, on the E-type builds, lets the reader report to a server on the site network. Our interface guide compares cable distances and wiring.

For software integration, the SDK includes sample code in C#, Visual C++, VB, Java and Delphi, plus a test demo and a tag read/write and issuing demo. Writing tags always goes through the SDK or demo over serial, USB or TCP/IP. Wiegand is output only.

• Height and aim: mount the panel at the height the installation notes give (above 1.8 m for the U630-M; the U640-M and U650-M notes are based on a 2.2 m pole), tilt it toward the point where the tag passes and aim along the lane rather than across it.
• RF power: start below maximum and raise it until the intended zone reads reliably. Radio rules limit radiated power (EIRP or ERP), which adds antenna gain to the output power, so with 7–12 dBi of gain, full 30 dBm output can exceed your local limit. See UHF frequency bands by country.
• Trigger input: wire a loop detector or photo-beam when you want reads only while a vehicle is in position.
• Windshield tags: some windshields have a metallic coating that blocks UHF. Fit the tag in the uncoated area and test on real vehicles.
• Test with your own tags at the final mounting position before rollout. The UHF read range guide explains why results differ between sites.

An integrated reader is the right tool for a fixed read point such as a gate, lane or dock door. Most projects also need a way to issue and check tags. A UHF desktop reader/writer numbers tags at a desk before they are fitted, and a handheld UHF reader helps check tags on vehicles or assets in the field. For lane layouts and controller wiring at car parks, see RFID readers for parking and boom barrier gates. Our guide to fixed, integrated and handheld UHF readers compares the formats, and the UHF RFID readers page lists every UHF model.