Design of a Microstrip Diplexing Filtering Power Divider

A diplexing filtering divider is proposed by using arbitrary even-order Butterworth-type filtering transformers and two extra matching lines. The matching design is similar to that of the T-junction design of a conventional diplexer. Therefore, the required matching conditions can be easily achieved by designing two properly 50-Ω lines. The proposed circuit has been carefully examined for a diplexing 2nd-order filtering divider.