Voltage-controlled oscillator

An apparatus, comprising:

• a first transistor and a second transistor, first terminals of the first and second transistors electrically coupled to a pair of first output nodes, a control terminal of the first transistor electrically coupled to the first terminal of the second transistor, a control terminal of the second transistor electrically coupled to the first terminal of the first transistor;
• a third transistor and a fourth transistor, first terminals of the third and fourth transistors electrically coupled to a pair of second output nodes, a control terminal of the third transistor electrically coupled to the first terminal of the fourth transistor, a control terminal of the fourth transistor electrically coupled to the first terminal of the third transistor;
• a capacitance unit electrically coupled to at least one pair of the pair of first output nodes and the pair of second output nodes;
• a first inductive unit configured to magnetically couple one of the first output nodes to one of the second output nodes;
• and
• a second inductive unit configured to magnetically couple the other of the first output nodes to the other of the second output nodes;
• wherein the first inductive unit comprises:
• a first inductive element electrically coupled to one of the second output nodes, the first inductive element configured to be DC-biased;
• wherein the second inductive unit comprises:
• a second inductive element electrically coupled to the other of the second output nodes, the second inductive element configured to be DC-biased.

A method comprising:

• DC-biasing a first inductive element which is magnetically coupled to a second inductive element;
• DC-biasing a third inductive element which is magnetically coupled to a fourth inductive element;
• wherein the second and fourth inductive elements are electrically coupled to a first cross-coupled transistor pair at a pair of first output nodes, and the first and third inductive elements are electrically coupled to a second cross-coupled transistor pair at a pair of second output nodes;
• generating signals having oscillation frequency at the pair of first output nodes and at the pair of second output nodes.