Method of designing impedance transformation circuit

A method of designing an impedance transformation circuit including a transformer circuit connected between a first high-frequency circuit and a second high-frequency circuit and a first inductance element and a second inductance element coupled to each other, wherein the first inductance element and the second inductance element are interlayer-coupled to each other, the second inductance element includes at least two layers of loop conductors, and the loop conductors sandwich the first inductance element in a stacking direction, the method comprising the steps of:

• a first step of determining a required transformer ratio of the transformer circuit based on an impedance of the first high-frequency circuit and an impedance of the second high-frequency circuit;
• a second step of determining a coupling coefficient between the first inductance element and the second inductance element, an inductance of the first inductance element, and an inductance of the second inductance element;
• a third step of determining a shape of the second inductance element;
• and
• a fourth step of determining a shape of the first inductance element such that the first inductance element is formed of at least two layers of loop conductors, and determining an interlayer distance between the loop conductors such that an inductance value of the first inductance element is a desired value.