Microstrip filters Based on Open Stubs and SIR for High Frequency and Ultra-Wideband Applications

This paper includes two new microstrip filterconfigurations for high frequency and Ultra-Wide Band applications. The first proposedfilter is a composition of four parallel open-circuited stubs connected by optimizedfractal-structured microstrip line. The filter response is a combination ofthree passing regions, namely low pass from 0.1 GHz to 3 GHz, band-pass from4.5 GHz to 9 GHz and high pass from 10.5 GHz to 13 GHz, separated by tworejection regions from 3 GHz to 4.5 GHz and 9 GHz to 10.5 GHz. Deep and sharprejection regions reaching up to -44.6 dB with 40 % fractional bandwidth (FBW)are observed with a good electrical performance. Furthermore, with a comparative table, the advantagesof this proposed BSF in terms of FBW, compactness and insertion loss arecompared with recently reported related studies. Secondly a dual-band band pass filter implementing a Stepped-Impedanceresonator (SIR) and a modifiedH-shaped structure is presented. This filter isdesigned to operate in a low pass region up to 3.58 GHz and a band pass regionfrom 15.38 to 21.65 GHz, with a wide stopband region between 4.46 and 14.07 GHz. The simulated andmeasured results are in good agreement. Compared to its peers, the compact sizeand low price allow for a wide application of these filter configurations,while passing frequencies allow operation in the unlicensed frequency spectrum,which is popular for high-speed communication