  Surface acoustic waveguides are increasing in interest for (bio)chemical
detection. The surface mass modification leads to measurable changes in the
propagation properties of the waveguide. Among a wide variety of waveguides,
Love mode has been investigated because of its high gravimetric sensitivity.
The acoustic signal launched and detected in the waveguide by electrical
transducers is accompanied by an electromagnetic wave; the interaction of the
two signals, easily enhanced by the open structure of the sensor, creates
interference patterns in the transfer function of the sensor. The influence of
these interferences on the gravimetric sensitivity is presented, whereby the
structure of the entire sensor is modelled. We show that electromagnetic
interferences generate an error in the experimental value of the sensitivity.
This error is different for the open and the closed loop configurations of the
sensor. The theoretical approach is completed by the experimentation of an
actual Love mode sensor operated under liquid in open loop configuration. The
experiment indicates that the interaction depends on the frequency and the mass
modifications.
