Practical design considerations on lumped element filters for microwave applications

In the low microwave frequency range between 1 and 3 GHz, the design and implementation of lumped element filters poses numerous problems. Practical design considerations are discussed in this paper, and are applied in the implementation of a 7^th order elliptic lowpass filter with 1.0 GHz cutoff frequency, and a wideband bandpass filter with more than 1.0 GHz bandwidth at a central frequency of 1.5 GHz. Good performances are demonstrated, and compared with simulation results. The limitations are also shown when similar lumped elements are applied in narrowband application