Multiple YIG oscillator

YIG oscillator apparatus having an apparatus output, comprising:

• a first oscillator circuit having an oscillator output and including as a component a first YIG resonator, said first oscillator circuit outputting a first oscillator signal having a frequency which is related to the strength of the magnetic field containing said first resonator by a first function;
• a second oscillator circuit having an oscillator output and including as a component a second YIG resonator, said second oscillator circuit outputting a second oscillator signal having a frequency which is related to the strength of the magnetic field containing said second resonator by a second function;
• magnetic field generating means for generating a single magnetic field, said first and second resonators both being disposed in said single magnetic field;
• and
• switch means for providing to said apparatus output an output signal responsive to selectably said first oscillator signal or said second oscillator signal.

YIG apparatus having an apparatus output node, said apparatus comprising:

• a first oscillator circuit having a first output and including a first YIG sphere as a reactive component and an FET as an active component;
• a second oscillator circuit having a second output and including a second YIG sphere as a reactive component and a bipolar transistor as an active component;
• an electromagnet including a pair of winding terminals for applying a desired current thereto to control the strength of the magnetic field generated by said electromagnet, said first and second YIG spheres both being disposed in said magnetic field;
• and
• switch means for outputting selectably a signal from said first or second output signal on said apparatus output node.

YIG apparatus having an apparatus output node, first and second positive supply terminals, a negative supply terminal, a ground terminal and a pair of winding terminals, said apparatus comprising:

• a magnetic core forming a closed shell and having a first pole piece extending inwardly from said shell, the free end of said first pole piece constituting a first pole surface, said first pole piece being substantially cylindrical and tapering to the shape of said first pole surface, said core further having a second pole surface magnetically opposite said first pole surface, said first and second pole surfaces defining an air gap there between;
• a winding wrapping at least a portion of said first pole piece and electrically coupled between said pair of winding terminals;
• a circuit board disposed inside said closed shell and supporting first and second oscillator circuits, said first oscillator circuit having a first output and said second oscillator circuit having a second output,
• said first oscillator circuit including:
• a first YIG sphere,
• an FET having a gate and first and second current path terminals,
• means for coupling said gate of said FET to ground via said first YIG sphere,
• means for coupling said first current path terminal to said first positive supply terminal via an impedance,
• means for coupling said second current path terminal to ground, and
• means for coupling said first current path terminal to said first output;
• said second oscillator circuit including:
• a second YIG sphere,
• a bipolar transistor having a base, a collector and an emitter,
• means for coupling said emitter of said transistor to said negative supply terminal via said second YIG sphere,
• means for coupling said base of said transistor to ground, and
• means for coupling said collector of said transistor to said second positive supply terminal via an impedance, and for coupling said collector of said transistor to said second output;
• said first and second YIG spheres being disposed proximately on said circuit board and inside said air gap, at least said first pole surface of said magnetic core having an elongated shape which is slightly larger than necessary to cover both said first and second spheres;
• said circuit board further supporting a first diode have an anode coupled to said first output and a cathode coupled to said apparatus output node;
• and
• a second diode having an anode coupled to said second output and a cathode coupled to said apparatus output node, said first and second positive supply terminals being distinct to permit application of power to selectably said first or second oscillator circuits.