Does the STRU3993 need an RFID antenna, what kind and to which pins?

[ZOsie.1]

What kind of RFID antenna do I need to use the STRU3993 in an application and to which pins do I connect the antenna to in order to operate the device, thank you so much

[Bart Herse]

Hi ZOsie.1,

depending on the targeted frequency range, the type of application and other factors, the antenna should be chosen.

What is common is the impedance: 50 ohm.

Typically far field patch antennas are in use but also near field antennas are possible if the application demands it.

Please check with Times-7, Laird, MTI, etc... for available RFID antennas.

ST25RU3993 has not a dedicated antenna pin but TX and RX pin pairs (ports) since transmission path and reception path need to be isolated.

Keep in mind that for passive or battery assisted RFID the reader needs to transmit RF power while receiving transponder data.

Please check the available documentation on our website how external components connect to the TX and RX ports of ST25RU3993.

You will also find information about the external circuity that is required to build a complete the Rain RFID reader by referring to the schematics and layout of the ST25RU3993-HPEV evaluation reader.

Cheers,

B

[ZOsie.1]

Hey Bart,

Sorry so my team and I are a tad confused still with hooking up the antenna.

It looks clear to use that we need to use thee RFO and MIX_IN pins however there are a few components we are having difficulty agreeing on, this is from Figure 2 of the Datasheet

Our question can we connect the antenna directly or do we need either an impedance matching circuit and a filter or do both need to be provided?

Thank you so much for the time

[Bart Herse · Accepted solution]

Hello ZOsie.1,

figure 2 in the datasheet does only show basic building blocks of a Rain RFID reader system.

Please find the documentation of the evaluation reader ST25RU3993-HPEV on our website.

There you can find the Altium schematic, layout and BOM. All is available as a PDF document if you do not have Altium available or conversion to another EDA tool should not work out.

Cheers,

B