The power transfer mechanism of MMIC spiral transformers and adjacent spiral inductors

Abstract

The WATMIC-EMsim software is currently being used to analyze the coupling between the two coils of an MMIC (monolithic microwave integrated circuit) transformer and between two adjacent MMIC square spiral inductors. For the transformer it is found that the simple magnetic coupling in power transfer between the two coils only occurs at the low frequency end of the microwave range. For the adjacent inductors, it is found that the coupling S/sub 21/ is very small. It starts at -26 dB when the two spirals nearly touch and rapidly drops off a function of 1/d/sup 7/, where d is the center-to-center separation between the two spirals.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>