What is the concept of Compact microstrip resonant cell-CMRC

What is the concept of Compact microstrip resonant cell-CMRC?

Why it can employ to design for size reduction?

Here, CMRC may be refer to electromagnetic bandgap microstrip resonant unit cell. Such kind of structrue can be employed to realize right/left-handed structures, and it can also be used to achieve slow wave (large propagation constant) to reduce physical size of microwave components.