  Superconducting on-chip filter-banks provide a scalable, space saving
solution to create imaging spectrometers at millimetre and sub-millimetre
wavelengths. We present an easy to realise, lithographed superconducting filter
design with a high tolerance to fabrication error. Using a capacitively coupled
$\lambda/2$ microstrip resonator to define a narrow ($\lambda/\Delta\lambda =
300$) spectral pass band, the filtered output of a given spectrometer channel
directly connects to a Lumped Element Kinetic Inductance Detector (LEKID). We
show the tolerance analysis of our design, demonstrating $<11\%$ change in
filter quality factor to any one realistic fabrication errors and a full
filter-bank efficiency forecast to be 60\% after accounting for fabrication
errors and dielectric loss tangent.
