Planar balun structure

A multilayer packaged integrated circuit device comprising:

• a first layer comprising a balun structure for routing millimetre-wave radar signals;
• and
• a second layer comprising a conductor connected to the single-ended side of the balun structure by a conductive via connecting the first and second layers,
• wherein the balun structure comprises:
• the single-ended side;
• a differential side;
• a half-wavelength path connecting the differential side to the single-ended side and surrounding the single-ended side.

A method of designing a planar balun structure for routing millimetre-wave radar signals, the balun structure comprising:

• a single-ended side;
• a differential side;
• a half-wavelength path connecting the differential side to the single-ended side, wherein the half-wavelength path forms a conductor path around the single-ended side, the single-ended side comprising a central conductor and a radial conductor path extending between the central conductor and the half-wavelength path,
• the method comprising adjusting an angle between the radial conductor path and the pair of linear parallel conductors to tune a common-mode rejection resonance frequency of the balun structure.