Pseudo-elliptic bandpass filter with subharmonic stubs

A simple bandpass filter that approximates equal ripples in both the pass band and the stopband is described. The filter comprises two stubs, resonant at one-half and one-quarter of the centre frequency, respectively, and a series overlay capacitor. The filter has a performance comparable to that of a third-order elliptic function filter and has a practical bandwidth of 16–34%.