The invention relates to a wireless instrument (1) includes a wristband (2) having a first (2a) and a second (2b) band portions connected to opposite edges of a casing (3), each of the first and second band portions having upper and lower surfaces. A first (4a) and a second (4b) loop antennas are embedded respectively in the first and second band portions and extend between the corresponding upper and lower surfaces, both loop antennas being connected through the opposite edges of the casing to a first (5a) and a second (5b) tuning circuits. the first and second tuning circuits are connected to an antenna receiver (6) arranged in said casing and together in a hybrid manner via an interconnection circuit (7), both tuning circuits being connected partially in parallel and partially in series.