Tunable inductor

A tunable inductor comprising:

• an elongate mandrel having a central axis, a first end, an opposed second end, an outer surface and an inner surface defining an inner cavity, and having a helical groove of predetermined pitch formed on said outer surface and extending in a direction from said first end toward said second end;
• a wire having a diameter, a first end and a second end, said wire being positioned within said helical groove of said mandrel and wound about said central axis of said mandrel;
• and
• a turn member protruding from said outer surface of said mandrel for redirecting said wire from said helical groove back toward said first end of said mandrel in a direction substantially parallel to said outer surface of said mandrel.

An electronic filter comprising at least one tunable inductor, said tunable inductor comprising:

• an elongate mandrel having a central axis, a first end, an opposed second end, an outer surface and an inner surface defining an inner cavity, and having a helical groove of predetermined pitch formed on said outer surface and extending in a direction from said first end toward said second end;
• a wire having a diameter, a first end and a second end, said wire being positioned within, said helical groove of said mandrel and wound about said central axis of said mandrel;
• a turn member protruding from said outer surface of said mandrel for redirecting said wire from said helical groove toward said first end of said mandrel in a direction substantially parallel to said outer surface of said mandrel;
• and
• a flange proximate said first end of said mandrel and positioned substantially perpendicular to said central axis of said mandrel, said flange having at least one guide member, wherein said turn member is spaced a distance from said flange in the axial direction of said mandrel.

An electronic filter comprising at least one tunable inductor, said tunable inductor comprising:

• an elongate mandrel having a central axis, a first end, an opposed second end, an outer surface and an inner surface defining an inner cavity, and having a helical groove of predetermined pitch formed on said outer surface and extending in a direction from said first end toward said second end;
• a wire having a diameter, a first end and a second end, said wire being positioned within said helical groove of said mandrel and wound about said central axis of said mandrel;
• a turn member protruding from said outer surface of said mandrel for redirecting said wire from said helical groove toward said first end of said mandrel in a direction substantially parallel to said outer surface of said mandrel;
• and
• a flange proximate said first end of said mandrel and positioned substantially perpendicular to said central axis of said mandrel, said flange having at least one guide member, wherein said turn member is radially offset from one of said at least one guide member by an amount substantially equal to said diameter of said wire.

A tunable inductor comprising:

• an elongate mandrel having a central axis, a first end, an opposed second end, an outer surface and an inner surface defining an inner cavity;
• a flange proximate said first end of said mandrel and positioned substantially perpendicular to said central axis of said mandrel;
• a wire having a diameter, a first end and a second end, said wire being wound about said outer surface of said mandrel from a position proximate said first end of said mandrel toward said second end of said mandrel;
• a turn member positioned a distance from said flange in the axial direction of said mandrel and protruding from said outer surface of said mandrel, wherein said turn member redirects said wire in a direction substantially parallel to said outer surface of said mandrel back toward said first end of said mandrel;
• and
• means for maintaining the position of said wire with respect to said mandrel.

A tunable inductor comprising:

• an elongate mandrel extending in a first direction from a first end toward an opposed second end and having a central axis, an outer surface and an inner surface defining an inner cavity;
• a flange proximate said first end of said mandrel and positioned substantially perpendicular to said central axis of said mandrel, said flange having a first surface and an opposed second surface adapted to rest on a surface of a circuit board;
• an extension member extending beyond said flange in a second direction substantially opposite to said first direction, said extension member having an outer surface and an inner surface that is substantially contiguous with said inner surface of said mandrel to define an extension of said inner cavity of said mandrel;
• a wire having a diameter, a first end and a second end, said wire being wound about said outer surface of said mandrel from a position proximate said first end of said mandrel toward said second end of said mandrel;
• and
• a tuning member having an initial position located within the inner cavity of said extension beyond a flux field created by said wire wound on said mandrel, such that said tuning member in said initial position does not substantially affect the inductance of the inductor.