UWB range problems on a 10x7.5cm PCB with ceramic antenna on the edge


We have a device that uses DW1000 module. The PCB size is a 1.5 mm FR-4 that has 4 layers and 10cm x 7.5cm dimensions. We use ceramic UWB antenna places on the longer edge of the PCB with clearance zone all along this edge. Everything is according to antenna datasheet guidelines around the antenna (clearance zone, vias on the edge to connect grounds between the layers etc).

We noticed in our system tests that sometimes we have pretty big packet losses between our devices. We compute this loss by tracking the sequence id which is incrementing and put to the payload on each transmission, we count how many packets we miss over time. We do this test on 20 meters distance between devices in an open field under the sky, devices are installed about 1.5 meters above ground on a wooden stands.

We found out that results of our tests highly depend on the orientation of the devices. There are some orientations in which we get 0% looses and there are some orientations in which we get >90% packets loss.

Moreover we did similar tests of other devices that we have designed, on a much smaller PCB, with exactly the same antenna and DW1000 circuit, and also identical MCU and firmware, and we found out that these small devices always have 0% packets loss.

For now we think the problem that we have comes from the fact that our PCB is big and affects the ceramic antenna radiation pattern.

My question is, what could be a good solution to our problem? How could we modify the antenna circuit to fix our range problems? Thank you in advance for any hints.

Without the specific antenna details, layout and schematics it is very difficult to support. Can you share portion of the schematic? What channel are you using? Are you certain tha the RF configuration is correct, did you use a DWM1000 module to test against (or DWS1000)?