  We present a study of the effects of fabrication tolerances on the
performance of a planar array of double-sided split-ring resonators, printed on
two sides of a dielectric substrate and fabricated using a printed circuit
board (PCB) milling machine. The array is simulated and measured in an X-band
waveguide, and the measured resonant frequency is found to be 6.3% higher than
the predicted one. The sensitivity of the frequency response to several
possible fabrication and measurement errors is investigated, and the dominant
effect identified and demonstrated experimentally and in simulation.
