dielectric material in Microstrip Antenna

I'm have a basic question want to ask.

What the use of the dielectric material in Microstrip Antenna? Form a capacitance?

Thanks in advance.

The di-electric material will concentrate the electric field in to the space between the conductors. Greater the di-electric const smaller will be the structure of ANT. Because di-electric with bigger const will concentrate the e-field between the ANT elements.