MultiNav Pro+ BLE - does the RF front-end need any external matching network?

The MultiNav Pro+ BLE has the matching network integrated, so you don't need to add one externally - just make sure you're routing the RF trace to the antenna port with a 50 ohm impedance and keeping it as short as possible. That said, double-check the reference schematic in the hardware design guide because there are a couple of decoupling caps they recommend near the module that are easy to miss.

@William Wilson yeah the matching network is handled internally — that's part of what makes the module drop-in friendly. The external amplifiers and receiver sensitivity optimization that give it the extended range are already tuned and integrated, so your job on the PCB side is really just clean 50 ohm trace routing to the antenna connector and keeping that path short and away from noisy digital lines.

 

The decoupling caps tip from the previous reply is worth taking seriously — I've seen people overlook those and wonder why their sensitivity numbers are off. If you're finalizing your stackup now, also think about your ground plane continuity under the module; a solid uninterrupted ground reference makes a meaningful difference at 2.4 GHz.

Yep, James is right - matching is internal, but I'd really stress the 50 ohm trace part, we had a layout on an early rev where the trace was slightly too wide for our stackup and it caused enough mismatch to tank our range noticeably. Pull up the hardware design guide and run your trace geometry through a calculator before you pour copper.

Jumping in to second what Sarah said about the trace width - we got burned by the exact same thing on a 4-layer board where our prepreg thickness was a bit different than the default stackup assumptions. Definitely run it through a microstrip calculator with your actual stackup params before you commit, even a small delta in width can shift you off 50 ohms more than you'd expect at 2.4GHz.

Solid advice from everyone above - one more thing worth mentioning, if you're using a PCB antenna make sure you're leaving the keepout zone clear of copper fills on all layers, not just the top, that one catches people off guard more than you'd think. Also grab the reference layout files from the dev hub if you haven't already, they save a ton of second-guessing on the decoupling placement James mentioned.

All solid points above - one thing I'd add is if you're on a 4-layer board and using a controlled impedance stackup from your fab, just ask them directly for the trace width that hits 50 ohms for your specific prepreg/core combo, most fabs will just tell you and it takes the guesswork out of the calculator entirely. Saved me a whole respun board once doing it that way.

Karen's tip about asking the fab directly is so underrated, I do this every single time now and they usually come back with a specific width + tolerance range that's way more trustworthy than anything I'd punch into a calculator blind. Also worth asking them to include it in your fab notes so if you ever reorder with a slightly different stackup revision you have a paper trail of what changed.

To answer the original question directly - the MultiNav Pro+ BLE has the matching network built in, so you just need to present it with a 50 ohm trace to your antenna and you're good, no external matching components needed on your side. All the stackup and trace width stuff everyone's discussing is still super relevant tho, that 50 ohm handoff is where people trip up.

Oh and one more thing I should've added - if you do want to double check the matching is working as expected after assembly, a quick check with a VNA at the antenna feedpoint before you solder the antenna down goes a long way, even just eyeballing the return loss can tell you if something went sideways in the routing.

Joseph Williams already nailed the main answer but just to pile on - I actually laid out a board with the MultiNav Pro+ last quarter and had zero external matching components, went straight from the module RF pin to a 50 ohm CPW trace out to the antenna and it worked first shot, so the built-in matching is definitely doing its job. Just make sure your trace length is as short as you can reasonably make it, even with good impedance control every extra mm is an opportunity for things to go sideways.

Yep, can confirm what Joseph H said - I ran the same setup on a custom IoT tracker build, no external matching needed, just nail your 50 ohm trace and keep it tight. One thing I'd add tho: if you're going CPW make sure your ground pours on either side are stitched down properly or you'll get weird impedance creep that the built-in matching can't compensate for.

All good advice above - just want to second Jennifer's point on the CPW ground stitching, I got burned on an earlier rev because my via spacing was too wide and I had an impedance bump right at the module handoff that took me forever to track down. Keep those stitching vias tight, like every 1-2mm along the trace, and you'll save yourself a headache.