Implementation of a microwave elliptical low pass filter with radial stubs

Actual paper describes two implementation methods of an elliptical low pass filter using copper disc sectors on a PCB substrate. The main idea was to replace the series resonant branches of the filter circuit with radial stubs, which have the same equivalent circuit at high frequencies. Different approaches of the shapes and placement of the radial stubs were made during the study. Substrate material of the printed circuit board and the dielectric permittivity variation as a function of frequency were also characterized. Radial stubs are largely used for decades in microwave applications and they created a solid background for further studies or scientific research.