A microstrip line is a type of open planar transmission line that consists of a dielectric substrate medium with a ground plane on the lower side and a conducting strip
on the upper side.
Microstrip line is now one of the most widely used transmission lines for MICs. Active devices (diodes and transistors), lumped circuit elements (capacitors, resistors, inductors), dielectric resonators, and antennas can be easily incorporated into the circuit. Compared with the traditional bulky and heavy metallic waveguides and coaxial lines, the planar microstrip structures are smallsize, lightweight, easy for mass production, and inexpensive.