Patent ID: 8600330

Claim:
A filter arrangement for filtering a radio signal comprising at least one first filter stage, the at least one first filter stage comprising a divide stage for dividing a filter stage input signal into at least a first signal portion, and at least a second signal portion, wherein the at least a first signal portion is passed to at least a first divide stage output and the at least a second signal portion is passed to a at least second divide stage output, at least a first filter element comprising a first filter element input being connected to the first divide stage output and a first filter element output for providing at least a first filtered signal, at least a second filter element comprising a second filter element input being connected to the second divide stage output and a second filter element output for providing at least a second filtered signal, a combine stage for combining the first filtered signal, received at the first combine stage input and the second filtered signal, received at the second signal combiner input into a filter stage output signal, wherein at least one of the first filter element or the second filter element is a duplex filter with a first transmit port for passing a signal in a first frequency band to a first antenna port of the duplex filter and a first receive port for receiving a second signal in a second frequency band from the first antenna port, and wherein one of the first receive port of the duplex filter or the transmit port of the duplex filter is connected via an impedance to a reference level.