Attach an antenna to the module

The VTAP50‑MOD reader module has no on‑board antenna. Before you can use any VTAP functionality, it requires connection of an external antenna, with a suitable matching circuit, to the VTAP50‑MOD reader module.

There are options for your first step(s), depending on the stage of your development project:

  • Assemble the VTAP50‑MOD reader module with an already procured matching circuit and antenna.

  • Procure or design a suitable antenna and matching circuit, to suit your integration, which might involve building the required matching circuit into the antenna design;

These are discussed in the sections below (click on one for more information):

If you bought a VTAP50 reader module (VTAP50‑MOD) with a separate matching circuit designed for a specific off‑the‑shelf or proprietary antenna (VTAP50-M2-xx) you will need to assemble these components.

Attaching an external antenna to the VTAP50 module uses the 12‑pin expansion header (also used to connect external LEDs).

Expansion header to connect external NFC antenna

Expansion header to connect external antenna

The pins 1 and 2 on the expansion header are used for external antenna connection.

Attach the matching circuit to this 12‑pin header. Then attach the antenna to the matching circuit board, as in the example below.

Assembly of VTAP50-MOD with VTAP50-M2-A1 tuning board and Molex antenna

Assembly of VTAP50-MOD reader module with matching circuit and antenna

CAUTION: Always ensure sufficient clearance between the VTAP antenna and other RF transmitters, to avoid electromagnetic interference between equipment. Clearance required varies between antennas, depending on antenna size, power and sensitivity.

If you have not yet chosen or designed an antenna and matching circuit, Dot Origin can provide support for integrating off‑the‑shelf or custom NFC antennas with VTAP25, VTAP50 and VTAP100 readers. Important considerations and examples of tuning circuits suited to specific off‑the‑shelf antennas are provided in the Application Note about external antennas.

Note: The VTAP50‑OEM reader board has been RF/EMC tested with its integrated loop antenna, printed on the PCB. The VTAP25-MOD is RF/EMC tested with a reference host board.

When a new external antenna is attached to a VTAP50 reader, or a VTAP25 is embedded in a host board with a new antenna design, the new arrangement will require corresponding matching circuits and EMC approvals.

 

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