Broad-Banding and Changing Operation Frequency of Circulator

Broad-banding of a circulator and changing of operation frequency of a lumped-element circulator are discussed. The point of broad-banding is to represent the circulator in a distributed element equivalent circuit. The improvement of the relative bandwidth was between 10 and 20 percent. The point of changing of operation frequency is to use a variable capacitance diode instead of a fixed one. The result is that the operating frequency changed from 120 to 220 MHz with a bias voltage change from 2 to 10 V.