Differential Impedance Transformer with Bandpass Filter Function

Abstract

Novel differential impedance transformer with the function of balanced bandpass filter on the base of coupled line is proposed. This transformer is composed of two identical coupled-line sections with cross-symmetrical loaded terminations. Two connected sumself such loads form the transmission line which connects the coupled-line sections. The network extended in the direction of input and output ports by segments of single transmission line which provide the matching with ports. The practical design procedure of this transformer is presented and explained. The impedance transformation for a differential mode can be achieved in wide passband with low in-band insertion loss and with efficiently common-mode rejection. The theoretical predictions are validated by simulation of proposed structure.