  A superconducting boron doped nanocrystalline diamond (B-NCD) coplanar
waveguide resonator (CPR) is presented for kinetic inductance ($L_k$) and
penetration depth ($\lambda_{\rm{L}}$) measurements at microwave frequencies of
0.4 to 1.2 GHz and at temperatures below 3 K. Using a simplified effective
medium CPR approach, this work demonstrates that thin granular B-NCD films
($t\approx $ 500 nm) on Si have a large penetration depth
($\lambda_{\rm{L}}\approx 4.3$ to 4.4 $\mu$m), and therefore an associated high
kinetic inductance ($L_{k,\square} \approx $ 670 to 690 pH/$\square$). These
values are much larger than those typically obtained for films on single
crystal diamond which is likely due to the significant granularity of the
nanocrystalline films. Based on the measured Q factors of the structure, the
calculated surface resistance in this frequency range is found to be as low as
$\approx$ 2 to 4 $\mu\Omega$ at $T<2$ K, demonstrating the potential for
granular B-NCD for high quality factor superconducting microwave resonators and
highly sensitive kinetic inductance detectors.
