Ultra-wideband 180 degree hybrid for dual-band cellular basestation antenna

Abstract

Ultra-wideband 180° hybrids for feeding a radiator of one band of a dual-band dual-polarization cellular basestation antenna are disclosed. The hybrid comprises: metal plates configured in parallel as groundplanes, and a dielectric substrate disposed between plates. First and second metallizations are implemented on opposite exterior surfaces of substrate and are shorted together to keep metal tracks at same potential to form conductor. Plates and first and second metallizations form first stripline circuit implementing matched splitter with short-circuit shunt stub Sum input port is provided at one end and two output ports are provided at opposite ends. Branches of matched splitter narrow to provide gap between output tracks. Third metallization is disposed within substrate. First, second and third metallizations form second stripline circuit. Tracks of third metallization comprise quarter-length transformers of different widths. Difference input port is provided at one end of second stripline circuit and at short-circuit point of short-circuit shunt stub of first stripline circuit. Metal track extends across gap of first stripline circuit.