Quad-band unequal power divider with coupled line section using stepped-impedance transformers

A novel quad-band unequal power divider with coupled line section using stepped-impedance transformers is presented in this paper. Coupled lines section is used to achieve the necessary impedance transformation at four selected frequencies. The topology of the structure, different from conventional Wilkinson power divider, is the coupled lines instead of the transmission lines. In this paper the structure is presents on the RT5880 substrate with dielectric constant is 3.2, Using CST Microwave studio, by this substrates design there is simulated return loss is greater than 10 dB at center frequencies 9.8 GHz, 11.8 GHz, 19 GHz and 20.5 GHz. The average insertion loss is good and group delays are 0.6 ns at 9.8 GHz, 0.54 ns at 11.8 GHz, 0.47 ns at 19 GHz, 0.38 ns at 20.5 GHz within these quad-band. In addition, the isolations between the outputs ports are greater than 10 dB over these quad-bands.