800–5000 MHz ultra-wideband CPW balun

An ultra-wideband coplanar waveguide (CPW) balun for operation over 800–5000 MHz using a commonly used hybrid microwave substrate is proposed. The CPW balun consists of a multistage Wilkinson structure, an ‘X’-shaped phase inverting structure, bottom-bridges and via-holes. The proposed balun does not need any additional circuit area for the generation of out-of-phase characteristics, so its size is exactly that of the basis Wilkinson divider.