Layout considerations¶

Electrical and mechanical design files are available for download at the LumenRadio online support page.

MWA-N3 OEM module pad dimensions¶

Refer to the picture above. All units in mm.

Oblong 1.4 x 2.79 (oblong edge a half circle with diameter 1.4)
Small rectangles left edge 1.0 x 0.8 (red)
Small squares right edge 1.02 x 1.02 (blue)
Large square 2.0 x 2.0 (green)

Layout considerations for the main board¶

The MWA-N3 module has been specifically designed to achieve optimal RF performance. To maintain this, there are some important guidelines that is recommended to follow:

The use of ground planes also on the carrier board for the MWA-N3 module cannot be emphasized enough. Good decoupling of any high-speed digital circuitry utilized on the carrier board is a must. Many embedded type microprocessors today have clock frequencies with clocks or overtones that reach well into the GHz range. It is possible for an embedded design to pass any EMC certification and still cause disturbances that will block the RF reception of the MWA-N3 module. The sensitivity of the MWA-N3 receiver is -96dBm therefore it is recommended to keep disturbances below -100dBm in the frequency range of operation. A near field probe connected to a spectrum analyzer will show if there are any disturbances present on the 2.45 GHz band generated by the microprocessor or any other device that is placed on the main board. Pay special attention to readymade LAN-products "Server in a RJ connector". They pass EMC certifications, but some of them radiate badly on 2.45 GHz. If disturbances can be seen on a spectrum analyzer - then the MWA-N3 module will have impaired reception.
MWA-N3 OEM module has a supply voltage decoupling on the circuit board. The supply voltage still needs to be adequately filtered. If any disturbance or intermittent communication failures occur, as one of the troubleshooting steps; check the supply voltage for drop-outs, switch supply ripple etc.
The top layer of the carrier board PCB under the MWA-N3 module should be free from copper, non isolated GND planes, traces or vias as indicated in drawing below. The white solid line represents the MWA-N3 module board outer edge. There is a ground plane on the MWA-N3 module bottom layer, but there are also supply lines. It is an unnecessary risk to rely on solder mask lacquer for isolation. Minimum dimensions for ground plane clearance for optimum antenna performance are shown below.

Guidelines for optimal performance for the internal antenna¶

It is important to consider the guidelines for the internal antenna. Failure to do so may result in inferior performance.
The MWA-N3 module has been tested on 1.6mm carrier boards of the brands ITEQ IT180 and Isola 370HR. For optimal performance it is recommended to use those for the carrier board design or a PCB with similar specification.
The MWA-N3 module board edge shall align with the carrier PCB edge, and the area within the orange rectangle shall be free from any traces copper, or components an all carrier PCB layers.
The area marked with the striped -pattern is a keep-out area for any solid material including carrier board PCB material.

The keep-out area extends from the module PCB surface in the vertical directions as well. Note that the carrier board thickness can be included in the total distance below the module, so that given a 1.6mm carrier board, its standoff shall be minimum 3.4mm.