Design & analysis of a microstrip line multi band UWB filter

In this article, a simple and compact multi band Ultra Wide Band Pass Filter is implemented and electrical analysis of this filter is presented. The proposed filter consists of five short circuited stubs of quarter wave length and three embedded U-shaped open circuited stubs, each of length λ/4, in the ground plane. The notches provide good rejection at 4.6 GHz, 5.6 GHz and 8.5 GHz which removes the interference in UWB band for INSAT C-band, WLAN and X-band applications. The proposed structure is simulated on the commercially available CST MWS software and fabricated using GML1000 substrate with a dielectric constant of 3.2 and a height of 30mil. The frequency responses of this filter are obtained for the circuit model on SERENIDE, for structure simulated on CST MWS and the response measured on VNA. All three responses are showing close resemblance. This filter gives a better performance and is easily fabricated having dimension of about (0.99λg × 0.279λg) where λg = 0.030 m.