Novel filter design incorporating asymmetrical junction circulators

The authors have explored asymmetrical Y-junction circulator designs for narrowband applications. Exact circulation conditions are found for a general asymmetrical circulator. The circulator design allows the input and transmission ports to be at the same angular distance from the isolation port but not necessarily at 120°C. This feature allows the suppression of high-order mode excitations in ferrite disks. This implies that a wide-stopband filter can be realized using asymmetric circulators. Due to the off-resonance bias of the ferrites, this device can be used at high power levels