  We present broadband parametric amplifiers based on the kinetic inductance of
superconducting NbTiN thin films in an artificial (lumped-element) transmission
line architecture. We demonstrate two amplifier designs implementing different
phase matching techniques: periodic impedance loadings, and resonator phase
shifters placed periodically along the transmission line. Our design offers
several advantages over previous CPW-based amplifiers, including intrinsic 50
ohm characteristic impedance, natural suppression of higher pump harmonics,
lower required pump power, and shorter total trace length. Experimental
realizations of both versions of the amplifiers are demonstrated. With a
transmission line length of 20 cm, we have achieved gains of 15 dB over several
GHz of bandwidth.
