Fig. 4

Intramuscular electrodes. a Top view of the electrodes showing a distal contact (Electrode ‘A’), a proximal contact (Electrode ‘B’), and the bonding pads of the four electrode contacts. b Detail of the area where the distal and proximal electrodes are located. c Cross section of the intramuscular electrodes (not to scale). Gold and platinum are used as metallization layers for the electrode tracks and contacts (600 nm thick per layer), and polyimide is used as substrate and cover material. d Impedance measurement of the intramuscular electrodes in a bipolar arrangement (short circuited distal contacts against short circuited proximal contacts) in a 0.9% NaCl solution