Coplanar waveguide basics for MMIC and PCB design

Some of the views on the significance of coplanar waveguide (CPW) for microwave monolithic integrated circuits (MMICs) and printed circuit board (PCB) design. The most basic configuration for CPW consists of a center conductor strip on top of a dielectric substrate with two ground conductors. It is more suitable for broadband applications because it shows lower dispersion than microstrip. CPW MMIC low-noise amplifiers and power amplifiers can be pushed to submillimeter-wave frequencies due to substrate modes and coupling effects. The MIM capacitor, used in MIC and MMIC circuits, can be constructed to formed the black plate of the capacitor by the CPW groundplane and CPW signal line, which is connected onto the top plate of the capacitor. Bypass capacitors in CPW also benefit from low inductance to ground. The grounded CPW with single ribbon or wire bond can operate well to very high frequencies when substrate are well placed near the launch.