GB1181633A - Control Circuit - Google Patents

Abstract

1,181,633. Ferrimagnetic waveguide devices. MULLARD Ltd. 2 Feb., 1968, No. 5391/68. Heading H1W. A control device for guided electromagnetic wave energy comprises a ferrite, YIG or other ferrimagnetic element magnetically biased in the general vicinity of a resonance and a control lead so disposed that the element is responsive to the magnetic field of currents in the lead, the conductors of the lead being disposed so as to form a high-frequency transmission line. The control lead is used to switch the element between resonant and non-resonant conditions or to change the phase-shift, both effects being non-reciprocal as regards the transmitted wave. The element 17 may be supported in a rectangular waveguide upon a dielectric vane 19 which serves to concentrate the field in the vicinity of the element. The element may be provided with a jacket (not shown) of material having a dielectric constant equal to that of the ferrimagnetic material. The jacket improves impedance matching. The control lead 18 may take the form of a transmission line having conductors which pass along either side of the element and terminate in a resistive load which may be situated either inside or outside the waveguide. If a coaxial or other transmission line is used (instead of a waveguide) for the controlled wave, then one of the conductors of this line may also constitute a control conductor. The device may be used as an isolator in the receiver circuit of a TR apparatus, the control lead being connected to the control gate of the transmitter. It may also be used in a phaseshift circulator of the type comprising two hybrid devices (e.g. magic T's) coupled by two signal paths, one of which provides non-reciprocal phase-shift.