An ultrasound flow meter unit arranged to measure a fluid flow rate is provided, where the unit comprises a circuit board 502 which comprises an electronic circuit, a first ultrasound transducer 506 and a first conducting path 564 electrically connected to first ultrasound transducer and the electronic circuit, wherein the circuit board is a multi-layer circuit board and the first conducting path 564 is arranged at least partially between a first layer 581 and a second layer 582. In a further embodiment, there is provided an upper electrically conducting layer 586 and/or a lower electrically conducting layer 588 which substantially covers, respectively, the upper surface of the first layer 581 and the lower surface of the second layer 582.