  An isotropic three-dimentional perfect lens based on cubic meshes of
interconnected transmission lines and bulk loads is proposed. The lens is
formed by a slab of a loaded mesh placed in between two similar unloaded
meshes. The dispersion equations and the characteristic impedances of the
eigenwaves in the meshes are derived analytically, with an emphasis on
generality. This allows designing of transmission-line meshes with desired
dispersion properties. The required backward-wave mode of operation in the lens
is realized with simple inductive and capacitive loads. An analytical
expression for the transmission through the lens is derived and the
amplification of evanescent waves is demonstrated. Factors that influence
enhancement of evanescent waves in the lens are studied and the corresponding
design criteria are established. A possible realization of the structure is
outlined.
