An ultrasonic sensor has: a diaphragm that includes at least two partial regions for emitting and/or receiving ultrasonic signals, the two partial regions possessing different resonance characteristics; and at least one electromechanical transducer coupled to the diaphragm, to which transducer a control signal having at least two different control signal frequencies is applied. In this context, a first control signal frequency is in the range of a resonant frequency of a first partial region of the diaphragm, and a second control signal frequency is in the range of a resonant frequency of a second partial region of the diaphragm. Alternatively, two electromechanical transducers are used, which are coupled to a diaphragm and have different resonance characteristics.