A micro-electromechanical switch (MEMS) (1; 1'; 1"; 101; 201; 301; 401) formed on a substrate (2; 2'; 2"; 202; 302; 402), the micro-electromechanical switch (1; 1'; 1"; 101; 201; 301; 401) comprising: - a first RF signal line (3; 3'; 3"; 103; 203; 303; 403) and a second RF signal line (4; 4'; 4"; 204; 304; 404) formed on the substrate (2; 2'; 2"; 202; 302; 402); - a deformable membrane made from a highly resistive material (5; 5'; 5"; 105; 205; 305; 405), the membrane (5; 5'; 5"; 105; 205; 305; 405) being kept, in a nondeformed state, spaced away from the substrate (2; 2'; 2"; 202; 302; 402) by anchoring means (6; 6'; 6"; 106; 206) secured to the substrate (2; 2'; 2"; 202; 302; 402), - an activation means (7; 7'; 7"; 107; 207; 307; 407) configured to deform the membrane (5; 5'; 5"; 105; 205; 305; 405) from its nondeformed state, - a substrate track formed on the substrate (2; 2'; 2"; 202; 302; 402), opposite the membrane (5; 5'; 5"; 105; 205; 305; 405), - a membrane track (8; 8'; 8"; 208; 308a, 308b) integrated into the membrane (5; 5'; 5"; 105; 205; 305; 405) and bearing a conductive contact zone (8a; 8a'; 8a"; 208a) opposite the substrate track configured to produce a conductive contact between the substrate track and the membrane track in a deformed state of the membrane (8; 8'; 8"; 208' 308a, 308b), the first RF signal line (3; 3'; 3"; 103; 203; 303; 403) and the second RF signal line (4; 4'; 4"; 204; 304; 404) being connected by means of at least one from among the membrane track (8; 8'; 8"; 208; 308a, 308b) and the substrate track, the switch (1; 1'; 1"; 101; 201; 301; 401) being in the on state when a signal is capable of circulating from the first RF signal line (3; 3'; 3"; 103; 203; 303; 403) to the second RF signal line (4; 4'; 4"; 204; 304; 404), and in the off state when a signal cannot circulate from the first RF signal line (3; 3'; 3"; 103; 203; 303; 403) to the second RF signal line (4; 4'; 4"; 204; 304; 404), characterized in that an membrane RF ground (9, 10; 9', 10'; 9", 10"; 109, 110; 209, 210; 309a, 309b, 310a, 310b; 409a, 409b, 410a, 410b) is integrated into the membrane (5; 5'; 5"; 105; 205; 305; 405), the membrane RF ground (9, 10; 9', 10'; 9", 10"; 109, 110;, 209, 210; 309a, 309b, 310a, 310b; 409a, 409b, 410a, 410b) being electrically connected to an RF substrate ground (11, 12, 13, 14; 11', 13'; 11", 13"; 111, 112, 113, 114; 211, 212, 213, 214; 311, 312; 411, 412) by means of anchors (6; 6', 6"; 106; 206), the membrane RF ground (9, 10; 9', 10'; 9", 10"; 109, 110; 209, 210; 309a, 309b, 310a, 310b; 409a, 409b, 410a, 410b) framing and being formed parallel to at least one from among the membrane track (8; 8'; 8"; 208; 308a, 308b) and the substrate track, such that the RF ground (9, 10; 9', 10'; 9", 10"; 109, 110; 209, 210; 309a, 309b, 310a, 310b; 409a, 409b, 410a, 410b) closely follows the RF signal path, to guide the propagation of the RF signal from the first RF signal line (3; 3'; 3"; 103; 203; 303; 403) to the second RF signal line (4; 4'; 4"; 204; 304; 404) when the switch is in the on state. - a first RF signal line (3; 3'; 3"; 103; 203; 303; 403) and a second RF signal line (4; 4'; 4"; 204; 304; 404) formed on the substrate (2; 2'; 2"; 202; 302; 402); - a deformable membrane made from a highly resistive material (5; 5'; 5"; 105; 205; 305; 405), the membrane (5; 5'; 5"; 105; 205; 305; 405) being kept, in a nondeformed state, spaced away from the substrate (2; 2'; 2"; 202; 302; 402) by anchoring means (6; 6'; 6"; 106; 206) secured to the substrate (2; 2'; 2"; 202; 302; 402), - an activation means (7; 7'; 7"; 107; 207; 307; 407) configured to deform the membrane (5; 5'; 5"; 105; 205; 305; 405) from its nondeformed state, - a substrate track formed on the substrate (2; 2'; 2"; 202; 302; 402), opposite the membrane (5; 5'; 5"; 105; 205; 305; 405), - a membrane track (8; 8'; 8"; 208; 308a, 308b) integrated into the membrane (5; 5'; 5"; 105; 205; 305; 405) and bearing a conductive contact zone (8a; 8a'; 8a"; 208a) opposite the substrate track configured to produce a conductive contact between the substrate track and the membrane track in a deformed state of the membrane (8; 8'; 8"; 208' 308a, 308b), the first RF signal line (3; 3'; 3"; 103; 203; 303; 403) and the second RF signal line (4; 4'; 4"; 204; 304; 404) being connected by means of at least one from among the membrane track (8; 8'; 8"; 208; 308a, 308b) and the substrate track, the switch (1; 1'; 1"; 101; 201; 301; 401) being in the on state when a signal is capable of circulating from the first RF signal line (3; 3'; 3"; 103; 203; 303; 403) to the second RF signal line (4; 4'; 4"; 204; 304; 404), and in the off state when a signal cannot circulate from the first RF signal line (3; 3'; 3"; 103; 203; 303; 403) to the second RF signal line (4; 4'; 4"; 204; 304; 404),