#1 April 13, 2017 00:06:38

evandavey
Registered: 2016-10-24
Posts: 2
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External Antenna Trace / Alternative Connector

Hi,

What is the best way to support a reverse SMA edge connector for an external antenna? Route the reference antenna trace to the edge of the board and reverse SMA connector? Or use a small u.fl to u.fl patch cable to the connector? Is there a reference design with this arrangement? Is there a recommended matching circuit? Ideally looking for a solution that keeps certification though understand this might not be possible.

We are using the module inside a product that has a 1.6mm steel body so need an externally mounted antenna (on a ~30cm cable). The antenna needs to use a reverse SMA connector accessible on the side of the board so that it can easily be connected/disconnected for product maintenance. For best IO trace layout, the module is positioned approximately 5cm from the board edge where the reverse SMA connector would need to be. Our board will be mounted in its own enclosure so the reference design u.fl connector would not be accessible.

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#2 April 14, 2017 13:30:07

SupportEngineer
Registered: 2016-03-11
Posts: 76
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External Antenna Trace / Alternative Connector

evandavey
Hi,What is the best way to support a reverse SMA edge connector for an external antenna? Route the reference antenna trace to the edge of the board and reverse SMA connector? Or use a small u.fl to u.fl patch cable to the connector?

(LAIRD/LSR): You must use a u.FL patch cable to use modular certification.

evandavey
Ideally looking for a solution that keeps certification though understand this might not be possible.

(LAIRD/LSR): The only possibility of using the modular certification would be to follow the reference design for the SaBLE-x. Documentation for this can be found in 330-0167 (Application Guide), pages 15-21. The reference design for the module can be found at the following link: https://www.lsr.com/embedded-wireless-modules/bluetooth-module/sable-x-ble-module#product-documents

evandavey
We are using the module inside a product that has a 1.6mm steel body so need an externally mounted antenna (on a ~30cm cable). The antenna needs to use a reverse SMA connector accessible on the side of the board so that it can easily be connected/disconnected for product maintenance. For best IO trace layout, the module is positioned approximately 5cm from the board edge where the reverse SMA connector would need to be. Our board will be mounted in its own enclosure so the reference design u.fl connector would not be accessible.

(LAIRD/LSR): We recommend using the SaBLE-x reference design with a u.FL to SMA bulkhead cable to attach to the panel mounted antenna. The antenna can then be disconnected at the SMA connector for any maintenance if necessary. If you do not wish to use the modular certification, then RF trace trouting from the module to an SMA edge connector would be an ideal solution. If good RF layout techniques are followed, no tuning would be necessary. Please keep in mind that this solution will require a controlled impedance PCB which will add cost.

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#3 April 14, 2017 23:19:18

evandavey
Registered: 2016-10-24
Posts: 2
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External Antenna Trace / Alternative Connector

OK, thanks. Will talk to the mechanical engineers again about using a panel-mount SMA connector.

Could keep certification by using a PCB mount SMA connector, on a separate board, with a u.FL connector placed close by (mirroring the module reference trace and PCB stack-up) and a small u.FL to u.FL patch cable between the module and the connector board? What about if the connector was on the same board, but the u.FL to u.FL patch cable is used instead of an extended PCB trace?

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#4 April 18, 2017 15:51:27

SupportEngineer
Registered: 2016-03-11
Posts: 76
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External Antenna Trace / Alternative Connector

evandavey
OK, thanks. Will talk to the mechanical engineers again about using a panel-mount SMA connector. Could keep certification by using a PCB mount SMA connector, on a separate board, with a u.FL connector placed close by (mirroring the module reference trace and PCB stack-up) and a small u.FL to u.FL

Do you mean an SMA?

evandavey
patch cable between the module and the connector board?

Yes, as long as the module layout matches the LSR reference design.

evandavey
What about if the connector was on the same board, but the u.FL to u.FL patch cable is used instead of an extended PCB trace?

Yes, this would work as well.

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