  The invisible axion is a well-motivated hypothetical particle which could
address two fundamental questions in modern physics - the CP symmetry problem
in the strong interactions and the dark matter mystery of our universe. The
plausible mass (frequency) range of the QCD axion as a dark matter candidate
spans from ueV to meV (O(GHz) to O(THz)). The axion haloscope using a resonant
cavity has provided the most sensitive search method in the microwave region.
However, experimental searches have been limited to relatively low mass regions
mainly due to the reduced cavity volume at high masses. As an effective
approach for high-mass axion searches, a unique cavity design, featured by
multiple identical cells divided by equidistant thin metal partitions in a
single cylindrical cavity, was proposed and successfully demonstrated. We
perform an in-depth study to characterize the multiple-cell cavity design and
discuss the various advantages it offers for high-mass axion searches.
