In this work, we investigate wave propagation through a zero index metamaterial
(ZIM) waveguide embedded with triangular dielectric defects. We provide
a theoretical guidance on how to achieve total reflection and total transmission (i.e.,
cloaking) by adjusting the defect sizes and/or permittivities of the defects. Our work
provides a systematical way in manipulating wave propagation through ZIM in addition
to the widely studied dielectric defects with cylindrical and rectangular geometries.