The Hall Effect Circulator-a Passive Transmission Device

Three-port nonreciprocal Hall effect devices have been made which circulate dc and ac signals either in a clockwise or counterclockwise sense. Forward losses of 17 db and reverse losses of 61 db have been obtained, giving a transmission ratio of 44 db. With the aid of simple six-resistor networks (or even simpler three-resistor networks) the nine short circuit admittance parameters of the circulator can be adjusted in a calculable manner. These networks permit asymmetrical circulators to appear symmetrical, to operate over a wide range of impedance levels, to operate with any value of magnetic field, and to introduce no loss-or even gain-if negative resistances are used. An analysis of the circulator, with and without the parallel networks, is included. It is shown that the minimum possible forward loss for a Hall effect circulator is 8.4 db.