GB1062584A - A lumped-constant non-reciprocal electric circuit - Google Patents

Abstract

1,062,584. Non-reciprocal networks. NIPPON ELECTRIC CO. Ltd. May 8, 1964 [May 9, 1963], No. 19213/64. Heading H3U. [Also in Division H1] A non-reciprocal circuit comprises a ferromagnetic body with two windings (each of one or more turns) at an angle to one another (preferably 90 degrees), a source of high-frequency current connected to one end of each winding, means for adjusting the relative phase of the currents in the windings, and means for applying a steady magnetic field to the ferromagnetic body at right-angles to the plane of the windings, whereby gyromagnetic resonance can occur in the body. In Fig. 2 current from a signal generator 30 flows through two windings 16, 17 on the body 15. Winding 16 has a series capacitor 26 to provide a series resonant circuit at the operating frequency (e.g. 140 Mc/s.) while winding 17 is shunted by a reactance 28 to form a parallel resonant circuit, a phaseadjusting capacitor 24 being also included. Depending on the reactances of 17 and 24, the element 28 may be inductive or capacitative. The circuit is adjusted so that the currents in 16 and 17 have at least one sinusoidal component which is equal in magnitude and 90 degrees apart in phase. If the supply frequency and the strength of the magnetic field are correctly adjusted so that gyromagnetic resonance occurs in the body, the attenuation of signals between points 20 and 22 will be very large in one direction and very small in the other. For other conditions, signals will pass in both directions but with different degrees of phase-shift. Three gyro-resonant bodies can be connected together with the first windings of each in star connection and the second windings in delta connection (Fig. 4, not shown). Three pairs of terminals are then provided, and the circuit is adjusted so that currents in one direction are shifted in phase by 60 degrees in each element while currents in the other direction are shifted by 120 degrees. The whole arrangement then acts as a directional three-port circulator with a total phase shift of 180 degrees in one direction and 360 degrees in the other. The three gyromagnetic elements can be mounted on the same ferromagnetic body (Fig. 1e, not shown) with slots cut to prevent undesired coupling between the three magnetic fields. The ferromagnetic body can be circular or polygonal (e.g. square). The windings can be rotatable about the axis of the body, and they may encircle the edge or pass through holes as in Fig. 1e. The ferromagnetic body can be inserted in a recess in an insulating former around which the windings pass. Reference has been directed by the Comptroller to Specification 863,866.