BE534335

• Format: Patent
• Language: English
• Subjects: AMPLIFIERS; BASIC ELECTRIC ELEMENTS; BASIC ELECTRONIC CIRCUITRY; DEVICES USING STIMULATED EMISSION; ELECTRICITY; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE; WAVEGUIDES

753,128. Gyromagnetic amplifiers. MARIE, G. R. P. Dec. 17, 1954 [Dec. 28, 1953], No. 36652/54. Class 40 (4). An ultra-high-frequency amplifier adapted to be inserted in series between two coaxial cylindrical wave guides 4, 5 dimensioned for propagation of energy in the TE01 mode comprises a cylindrical resonator 2 coaxial with the guides, and containing a rod 3 of insulating material of very high permeability (e.g. ferrite) arranged along its axis; the rod 3 being subject to a steady magnetic field due to the magnet 6; and the resonator being further excited by a circularly polarized TM11 wave of frequency lower than (preferably /10 of) the frequency of the wave to be amplified. As shown the latter wave is introduced from a source 13 via a rectangular waveguide 12 and a slot 11. Owing to the Faraday effect the resonance frequencies for the two directions of rotation are different so that if one of these frequencies is chosen, the resonator is automatically excited by circularly polarized waves with the associated direction of rotation. The rotation of the magnetic field causes precession and nutation of the uncompensated electrons of the ferrite and the angular frequency of the input wave is arranged to be approximately equal to (slightly less than, in practice) the natural angular frequency of nutation of the electron. The output wave derives its energy from the nutation motion of the electron, which is correspondingly damped and this in turn influences the precession motion which has to be maintained by energy derived from circularly polarized auxiliary wave. It is shown mathematically that for optimum results the auxiliary wave frequency must be approximately equal to the frequency of the conventional ferromagnetic resonance.