What is microstrip?

A microstrip is a specialized type of planar transmission line used in microwave-frequency circuit boards. It consists of a precise conducting strip routed on the top layer of a dielectric board, with a continuous solid ground plane on the bottom layer. This geometry provides a constant characteristic impedance, which is critical for minimizing signal reflections in high-frequency RF and microwave circuits. By strictly controlling the width of the trace and the thickness of the dielectric, designers can create exact impedance matches without needing bulky coaxial cables. Common distractors might trick you into thinking it involves miniature coax or physical shielding. However, a microstrip is specifically a printed circuit board fabrication technique, not a separate physical cable or a type of shielding wrap.