FEM Analysis, Design and Optimization of a Compact Bandpass Filter for Low-power UWB Communications Applications

With the aid of the finite element method (FEM) and a commercial EM simulator, the analysis, the design and the optimization of a compact bandpass filter using interdigital coupled microstrip lines with performance suitable for lowpower UWB communications applications, are presented. The design of the compact UWB bandpass filter is based on the use of impedance steps and coupled-line sections, whereas the simulation of its frequency response ([S]) is done using MATPAR software and it is based on the electromagnetic (EM) parameters for each section of line forming the bandpass structure. The center frequency around 6.85 GHz was selected, the bandwidth is between 2.5-10.2 GHz, the insertion-loss amounts to 0.15 dB and the return loss is found better than 15 dB over a large portion of bandwidth. For the selected center frequency and on RT/Duroid 6006 substrate with a dielectric constant of 6.36, our UWB BPF is only 2.0 1.524 36.6 mm in size.