Electronic – 50 Ohm Board to Board Connector

connectorimpedance-matchingpcb-design

I'm trying to build a tunable bandpass filter for 140 to 1500 Mhz, and the design requires that I move the signal from a PCB with an SMA connector to another mounted about 3mm above it. I'm using board to board connectors for the other connections, but I wasn't sure whether it was possible to match 50 ohm impedance (or to get close enough) with a connector like that.

My question is, how should I move the signal from one pcb to the other with 50 ohm impedance? Is such a connection even possible in that little space, or is my approach fundamentally flawed?

Best Answer

You have perhaps two possibilities:

  1. Use a short piece of small diameter \$50\Omega\$ coax cable, folded and soldered directly to the boards: however, while nice for a prototype, this solution poses problems from the point of view of engineering and production.
  2. Use small RF/Microwave connectors like this one: I use this kind of objects from the year 2000 and, while the devices I use are designed for cable to board connection, there are devices designed for board to board connection, with board distances as low as \$2.5\mathrm{mm}\$. Also, there are many producers who offer such kind of devices.

Edit: I updated the answer by adding a link to the mating connector, precisely a plug, in order to have a board to board plug/receptacle couple of connectors. I stress the fact that the device shown are not exclusively produced by a single manufacturer, but there are several high quality producers that offers such devices.

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