The leakage and radiation characteristics of conductor-backed coplanar waveguide

From the analysis in full wave SDA, the leakage effect can be controlled by the thickness, dielectric constant of the substrate and the slot width of the CPW line, that is a structure of the circuit on a layer conductor-backed substrate and below a layer superstrate. Under the non-leakage condition, the characteristic impedance is sensitive to the strip width and it will drop before slot width reaches the value at which attenuation occurs. The leakage is dependent on the frequency, when the leaky wave arises there is a smaller expended angle between the two radiation main lobes at higher frequency. Using these properties, the non-leaky and leaky circuits can coexist on the same circuit board by choosing appropriate circuit dimensions.