Inductor structure and application thereof

A oscillator circuit, comprising:

• a five-terminal passive device comprising
• a first inductor coil comprising a first loop connected to a first terminal and a central terminal and a second loop connected to a second terminal and the central terminal, wherein the first loop and the second loop are configured in a figure-of-eight so that a current flowing in the first inductor coil circulates around the first loop in a first rotational direction and circulates around the second loop in a second rotational direction opposite the first rotational direction, and
• a second inductor coil comprising a loop that surrounds the first inductor coil, wherein a first end of the second inductor coil connects to a third terminal, a second end of the second inductor coil connects to a fourth terminal, and a midpoint of the second inductor coil connects to the central terminal;
• a first voltage-controlled oscillator circuit coupled to the first terminal and the second terminal of the five-terminal passive device;
• and
• a second voltage-controlled oscillator circuit coupled to the third terminal and the fourth terminal of the five-terminal passive device.