Broadband VHF/UHF circulators with tailored filter characteristics

A range of broadband lumped element circulators has been designed and developed in the VHF/UHF bands by considering the bandwidth limitations imposed by the ferrimagnetic material properties at these low frequencies. Selection of suitable materials consistent with the demands of the basic circulator junction design yields broadbandwidths with low transmission loss using filter matching techniques. An extension of these techniques allows the tailoring of the out-of-band response to provide a predictable degree of rejection at harmonic frequencies.