Apparatus (1; 21; 121) for detecting an object (8, 11, 12.1-12.3) in a substrate (3, 6) having a transmitting unit (54; 141; 161) with a first transmitting element (53.1) which is designed to transmit a first transmission signal (TX 1) into the substrate (3, 6), a receiving unit (56; 161) with a first, second and third receiving element (55.1-55.3; 162.1-162.3) which are designed to receive a received signal (TX 1 /RX 1, TX 1 /RX 2, TX 1 /RX 3) which is dependent on the first transmission signal (TX 1) and the properties of the object (8, 11, 12.1-12.3) and of the substrate (3, 6), a control and evaluation unit which is designed to control the transmitting and receiving units (54, 56) and to evaluate the received signals (TX 1 /RX 1, TX 1 /RX 2, TX 1 /RX 3), and a display unit which is designed to display the received signals (TX 1 /RX 1, TX 1 /RX 2, TX 1 /RX 3) evaluated by the control and evaluation unit, wherein the transmitting unit (54; 141; 161) has a second transmitting element (53.2) which is designed to transmit a second transmission signal (TX 2) into the substrate (3, 6), and a third transmitting element (53.3) which is designed to transmit a third transmission signal (TX 3) into the substrate (3, 6), wherein the first, second and third transmitting element (53.1-53.3) of the transmitting unit (54; 161) are able to be controlled independently of each other by the control and evaluation unit, wherein the first transmitting element (53.1) of the transmitting unit and the first receiving element (55.1) of the receiving unit as a first sensor element (47.1; 162.1), the second transmitting element (53.2) of the transmitting unit and the second receiving element (55.2) of the receiving unit as a second sensor element (47.2; 162.2), and the third transmitting element (53.3) of the transmitting unit and the third receiving element (55.3) of the receiving unit as a third sensor element (47.3; 162.3) are integrated in a first sensor unit (44; 122; 162), and wherein the sensor elements (47.1, 47.2, 47.3; 162.1, 162.2, 162.3) are able to be switched by means of the control and evaluation unit between a transmitting mode, in which a sensor element (47.1-47.3; 162.1-162.3) transmits a transmission signal (TX 1, TX 2, TX 3), and a receiving mode, in which a sensor element (47.1-47.3; 162.1-162.3) receives a received signal (TX 1 /RX 1, TX 1 /RX 2, TX 1 /RX 3, TX 2 /RX 1, TX 2 /RX 2, TX 2 /RX 3, TX 3 /RX 1, TX 3 /RX 2, TX 3 /RX 3), characterized in that the first, second and third sensor element (47.1, 47.2, 47.3; 162.1, 162.2, 162.3) are arranged in a nested arrangement in a first and second row, wherein the sensor element (47.3; 162.3) in the second row is arranged between the sensor elements (47.1, 47.2; 162.1, 162.2) in the first row. a transmitting unit (54; 141; 161) with a first transmitting element (53.1) which is designed to transmit a first transmission signal (TX 1) into the substrate (3, 6), a receiving unit (56; 161) with a first, second and third receiving element (55.1-55.3; 162.1-162.3) which are designed to receive a received signal (TX 1 /RX 1, TX 1 /RX 2, TX 1 /RX 3) which is dependent on the first transmission signal (TX 1) and the properties of the object (8, 11, 12.1-12.3) and of the substrate (3, 6), a control and evaluation unit which is designed to control the transmitting and receiving units (54, 56) and to evaluate the received signals (TX 1 /RX 1, TX 1 /RX 2, TX 1 /RX 3), and a display unit which is designed to display the received signals (TX 1 /RX 1, TX 1 /RX 2, TX 1 /RX 3) evaluated by the control and evaluation unit, wherein the transmitting unit (54; 141; 161) has a second transmitting element (53.2) which is designed to transmit a second transmission signal (TX 2) into the substrate (3, 6), and a third transmitting element (53.3) which is designed to transmit a third transmission signal (TX 3) into the substrate (3, 6), wherein the first, second and third transmitting element (53.1-53.3) of the transmitting unit (54; 161) are able to be controlled independently of each other by the control and evaluation unit, wherein the first transmitting element (53.1) of the transmitting unit and the first receiving element (55.1) of the receiving unit as a first sensor element (47.1; 162.1), the second transmitting element (53.2) of the transmitting unit and the second receiving element (55.2) of the receiving unit as a second sensor element (47.2; 162.2), and the third transmitting element (53.3) of the transmitting unit and the third receiving element (55.3) of the receiving unit as a third sensor element (47.3; 162.3) are integrated in a first sensor unit (44; 122; 162), and wherein the sensor elements (47.1, 47.2, 47.3; 162.1, 162.2, 162.3) are able to be switched by means of the control and evaluation unit between a transmitting mode, in which a sensor element (47.1-47.3; 162.1-162.3) transmits a transmission signal (TX 1, TX 2, TX 3), and a receiving mode, in which a sensor element (47.1-47.3; 162.1-162.3) receives a received signal (TX 1 /RX 1, TX 1 /RX 2, TX 1 /RX 3, TX 2 /RX 1, TX 2 /RX 2, TX 2 /RX 3, TX 3 /RX 1, TX 3 /RX 2, TX 3 /RX 3), characterized in that the first, second and third sensor element (47.1, 47.2, 47.3; 162.1, 162.2, 162.3) are arranged in a nested arrangement in a first and second row, wherein the sensor element (47.3; 162.3) in the second row is arranged between the sensor elements (47.1, 47.2; 162.1, 162.2) in the first row.