A liquid infusion device, comprising: a flexible drive tape having a plurality of holes aligned essentially linearly along the length of the drive tape, the plurality of holes spaced apart at a fixed increment; a drive shaft comprising at least one gear, the at least one gear comprising a plurality of teeth that align and engage the holes in the flexible drive tape; a plunger attached to or in communication with at least one end of the flexible drive tape; and a cartridge for containing a liquid medication for receiving the plunger and expelling the liquid medication upon movement of the plunger in the cartridge; characterized by: the flexible drive tape comprising a striated polymer, flexible in a longitudinal direction and rigid in an axial direction; the cartridge having a substantially elliptical geometry; the flexible drive tape being supported by rubber strips along its edges that are adapted to glide against the inner walls of the cartridge at its widest diameter, whereby the geometry of the cartridge provides a single channel at its widest diameter through which the plunger and drive tape can move longitudinally, whereas movement of the plunger and drive tape in other directions is substantially prevented; and a piezoelectric motor for advancing and retracting the flexible drive tape, wherein the piezoelectric motor turns the drive shaft, thereby advancing or retracting the flexible drive tape and driving the plunger into or out of the cartridge in an increment correlating to the fixed increment between holes. a flexible drive tape having a plurality of holes aligned essentially linearly along the length of the drive tape, the plurality of holes spaced apart at a fixed increment; a drive shaft comprising at least one gear, the at least one gear comprising a plurality of teeth that align and engage the holes in the flexible drive tape; a plunger attached to or in communication with at least one end of the flexible drive tape; and a cartridge for containing a liquid medication for receiving the plunger and expelling the liquid medication upon movement of the plunger in the cartridge; characterized by: the flexible drive tape comprising a striated polymer, flexible in a longitudinal direction and rigid in an axial direction; the cartridge having a substantially elliptical geometry; the flexible drive tape being supported by rubber strips along its edges that are adapted to glide against the inner walls of the cartridge at its widest diameter, whereby the geometry of the cartridge provides a single channel at its widest diameter through which the plunger and drive tape can move longitudinally, whereas movement of the plunger and drive tape in other directions is substantially prevented; and a piezoelectric motor for advancing and retracting the flexible drive tape, wherein the piezoelectric motor turns the drive shaft, thereby advancing or retracting the flexible drive tape and driving the plunger into or out of the cartridge in an increment correlating to the fixed increment between holes. the flexible drive tape comprising a striated polymer, flexible in a longitudinal direction and rigid in an axial direction; the cartridge having a substantially elliptical geometry; the flexible drive tape being supported by rubber strips along its edges that are adapted to glide against the inner walls of the cartridge at its widest diameter, whereby the geometry of the cartridge provides a single channel at its widest diameter through which the plunger and drive tape can move longitudinally, whereas movement of the plunger and drive tape in other directions is substantially prevented; and a piezoelectric motor for advancing and retracting the flexible drive tape, wherein the piezoelectric motor turns the drive shaft, thereby advancing or retracting the flexible drive tape and driving the plunger into or out of the cartridge in an increment correlating to the fixed increment between holes.