Design of microstrip power dividers with filtering functions

This paper presents the design of a novel microstrip power divider/combiner able to provide a selective bandpass filter. The structure consists of a combination of several T-junctions with novel configurations to generate frequency-variant couplings (FVC). These FVC also create n+1 transmission zeros in the frequency response. A practical design technique for this component is introduced, including figures and formulas for accurate and fast conception. To validate the design, a 1:8 power divider is fabricated and measured. The power divider generates a two-pole bandpass filter centered at 10 GHz. The proposed technique also provides three transmission zeros at 8.75, 11.75 and 12.25 GHz. The proposed technique can easily be extended to a different number of outputs.