  Pendry in his paper [Phys. Rev. Lett., 85, 3966 (2000)] put forward an idea
for a lens made of a lossless metamaterial slab with n = -1, that may provide
focusing with resolution beyond the conventional limit. In his analysis, the
evanescent wave inside such a lossless double-negative (DNG) slab is 'growing',
and thus it 'compensates' the decaying exponential outside of it, providing the
sub-wavelength lensing properties of this system. Here, we examine this debated
issue of 'growing exponential' from an equivalent circuit viewpoint by
analyzing a set of distributed-circuit elements representing evanescent wave
interaction with a lossless slab of DNG medium. Our analysis shows that, under
certain conditions, the current in series elements and the voltage at the
element nodes may attain the dominant increasing due to the suitable resonance
of the lossless circuit, providing an alternative physical explanation for
'growing exponential' in Pendry's lens and similar sub-wavelength imaging
systems.
