An apparatus measures properties of an object such as a heart in a patient (2). The apparatus includes an antenna (3, 4) for sending and/or receiving electromagnetic waves to and/or from the object (2) for measuring a property of the object. The antenna (3, 4) includes an electrically conductive element for functioning as an electrode for measuring a further property of the object. The electromagnetic waves are reflected by the object, causing a Doppler shift. The apparatus uses this shift to provide mechanical information about the object and uses the electrode to provide electrical information about the object, such as an electrocardiogram.
