RFID portals: bulk reading at passageways and gates

An RFID portal is a frame or arch over a passageway. A reader, several antennas and direction sensors capture all UHF tags carried or driven through the zone. A bag of linen, a trolley or a pallet is read as a complete group, with no item-by-item scanning and no need to stop the flow. We select a portal configuration for the passage geometry and operational task, then supply the equipment as part of the project.

Portal components

Reader. A fixed reader with 4–16 antenna ports; power is adjustable up to 33 dBm, so the zone is tuned to the specific passage rather than forcing the passage to fit the equipment.
Antennas. Usually circularly polarized, with 6–12 dBi gain, so tags can be read in any orientation; the position of linen inside a bag cannot be predicted.
Direction sensors. Infrared or photoelectric sensors mounted on posts; the order in which they trigger tells the system whether an item was brought in or taken out.
Alarms and automation. A relay output, audible/visual beacon and EPC-mask triggering allow the portal not only to record movement but also to raise an alert when an item is removed.
Software. Reconciles reads with documents, writes events to the accounting system and filters out stray tags.

Direction detection and exclusion of unrelated tags rely on RSSI. Using signal levels at the entrance and exit antennas together with the sensor-trigger sequence, the software determines the direction of movement and rejects tags located near the passage that did not actually move through it.

Types of RFID portals

Type	Code	Installation location	Read zone	Features
Frame portal (posts on both sides of a passage)	П2	Doors, gates, corridors	passage ~1.5–3 m between posts	Aluminium + acrylic; RS-232, TCP/IP, PoE, Wi-Fi interfaces
Overhead portal	П6	Passageways where posts obstruct trolleys and people	up to ~6 m from the antenna	Compact enclosure, IP65 protection; no floor space required
Modular portal (reader + remote antennas)	—	Warehouse gates, non-standard openings	configurable: 4–16 antennas, 6–12 dBi gain	Maximum flexibility for the geometry; IP55–IP65 protection for components
Tunnel portal (channel)	ПТ	Areas with conveyor feeding	inside the tunnel	A set of tags is read in a few seconds; RS-232, USB, RJ45
Anti-theft passage	—	Exits at hotels, health resorts and laundries	doorway	Reader with relay output, directional antenna, audible/visual beacon

All versions work with passive UHF tags using EPC Gen2 / ISO/IEC 18000-63.

BizData codes are our designations for standard selection configurations and are refined during project estimation.

How to choose a portal

Passage geometry. Width, height, wall materials and nearby equipment determine the number and placement of antennas. A portal for a wide gate is assembled from a fixed reader and remote antennas.
What passes through and how it is packed. Linen in bags, cartons on a pallet and tools in metal containers present different radio-channel conditions. Metal and wet textiles shield the signal, so we verify the configuration by testing rather than selecting from a catalogue. The ПТ tunnel version is available for conveyor-fed sets.
Whether direction is required. Direction sensors and RSSI processing are mandatory for received/issued tracking; a basic configuration is enough if only the fact of passage must be recorded.
Interfaces and integration. RS-232, Wiegand, TCP/IP and PoE: the portal must fit into the existing network and accounting system rather than require them to be rebuilt.
Frequencies for Kazakhstan. Kazakhstan uses the European ETSI 865–868 MHz range; equipment built only for the American FCC 902–928 MHz range is not suitable. The frequency grid is governed by national radio-spectrum rules, so we verify the range and power settings during equipment selection.

Typical scenarios

Laundry: receiving and issuing linen in bags. A П2 frame portal or П6 overhead portal at the receiving area reads sewn-in textile tags directly through the bag: how many items were received, who owns the linen, what went to wash and what returned. Issue completeness is reconciled automatically, so disputes with the customer are resolved with data instead of a manual recount. Learn more about the solution on the textile and workwear tracking page and about tag selection in the laundry RFID tag guide.
Warehouse: shipping and receiving gates. The portal captures pallets and cartons as a forklift passes and compares the actual contents with the document, exposing discrepancies before the vehicle leaves. Learn more about RFID for warehouses.
Asset movement control. Portals at transitions between rooms record the movement history of inventory and equipment; periodic counting becomes RFID stocktaking based on passage data.
Removal protection. An anti-theft passage responds to a tag with a specified EPC mask and raises an audible/visual alert if textiles or assets are taken outside the facility.

Not sure whether a portal can read through your bag or pallet? We will test actual samples in the RFID laboratory and, if needed, deploy an RFID pilot at one passage.

FAQ

Will a portal read every tag in a bag of linen?

Bulk reading is the normal operating mode of a UHF portal, but the result depends on how tightly the bag is packed and on linen moisture, because wet textiles absorb the signal. We therefore select power, antenna count and antenna placement by testing your actual bags rather than relying on specification-sheet figures.

How does a portal know whether an item was brought in or taken out?

It uses the order in which direction sensors on the posts trigger and the change in RSSI at the entrance and exit antennas. The software combines both signals into a received or issued event and sends it to the accounting system.

How should metal containers and trolleys be handled?

Metal shields and reflects the signal. Goods in metal containers require dedicated on-metal tags, and antenna placement must be verified by testing. This is a standard engineering task, but it is solved through measurement rather than guesswork.

Which frequency is required in Kazakhstan?

The European ETSI 865–868 MHz range. Portals built only for FCC 902–928 MHz (USA) are not suitable for Kazakhstan; we verify the range and power settings during equipment selection. Learn more in the article on EPC Gen2 and ISO/IEC 18000-63.

Select a portal for your project

Send us the passage dimensions and describe what moves through it. We will propose a portal configuration, test it with your samples and supply the equipment as part of the project.

+7 (701) 589-45-99 · info@bizdata.kz

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