New cross-coupled microstrip band reject filters

A new design of elliptic band reject microwave filters in microstrip technology is presented. Instead of the standard in-line configuration, compact filters are designed by exploiting the same coupling schemes that have been extensively used in designing elliptic and pseudo-elliptic bandpass filter with source-load coupling. Elliptic band reject filters of order 2 and 4 are designed using a commercial software package. To demonstrate the validity of the approach a prototype filter of fourth order was fabricated and measured.