Patent attributes
A balun including a single-ended port, a differential port and first and second sets of coupled transmission line sections. Each set has three coupled transmission line sections. The signal carrying terminal of the single-ended port is connected to an inner end of a third coupled transmission line sections in one of the sets, and the terminals of the differential port are connected to a respective outer end of a respective first transmission line. The balun is fabricated in a multi-layer insulating substrate with the single-ended port located on an upper surface of the substrate and the differential port located on a lower surface of the substrate. The balun is suitable for connection to a chip antenna mounted on a common carrier substrate.