Novel filter design incorporating asymmetrical stripline Y-junction circulators

Theoretical treatments of an asymmetrical stripline Y-junction circulator have been carried out. These include a formulation of the circulation conditions of an asymmetrical circulator as well as its transmission characteristics under wide-frequency-band consideration. It is found that filter designs incorporating circulators are very plausible and give rise to a narrow transmission band around the desired transmission frequency and a wide stopband extending many times the fundamental transmission frequency. In this design, high order mode excitations inherent in other filter designs are attenuated. In addition, owing to the off-resonance operation of the ferrites, present design could be applied under higher power conditions than traditional resonant ferrite filters