Patent ID: 9209772
Filing Date: 2015-12-08
Classification: H01P,H03H

Abstract:
1. An electrical filter for forwarding an electrical signal from a first port to a second port in a frequency-selective manner, the filter comprising: the first port comprising a first characteristic port impedance; the second port comprising a second characteristic port impedance; a filter core comprising a working impedance, wherein the working impedance is different from the first characteristic port impedance and from the second characteristic port impedance, wherein the filter core comprises a first filter core port, a second filter core port, a plurality of series impedance elements electrically coupled between the first filter core port and the second filter core port, and a plurality of shunt impedance elements, wherein the shunt impedance elements of the filter core are implemented using transmission lines electrically coupled to nodes which are electrically coupled between subsequent series impedance elements of the first filter core, wherein the shunt impedance elements of the first filter core are arranged in different conducting layers of a multi-layer structure, and wherein a transmission line used to implement a first shunt impedance element does not overlap a transmission line used to implement a second impedance element in a projection perpendicular to a main surface of the multi-layer structure; a first matching circuit electrically coupled between the first port and the filter core, wherein the first matching circuit is configured to perform an impedance matching between the first characteristic port impedance and a characteristic impedance presented by the filter core to the first matching circuit; and a second matching circuit electrically coupled between the second port and the filter core, wherein the second matching circuit is configured to perform an impedance matching between the second characteristic port impedance and a characteristic impedance presented by the filter core to the second matching circuit.