Patent ID: 8207799

Claim:
A network element for a wireless communication system, the network element comprising: an antenna system; a transmitter coupled to the antenna system to transmit radio frequency signals in a transmit frequency band via at least one antenna of the antenna system; and a receiver coupled to the antenna system to receive radio frequency signals in a receive frequency band different from the transmit frequency band via at least one antenna of the antenna system; at least one of the transmitter and the receiver comprising a radio frequency band reject filter, the band reject filter comprising: a coupler operable on an input signal applied to an input port to provide a respective output signal proportional to the input signal at each of a first output port and a second output port, the output signals having a phase shift between 45 degrees and 135 degrees with respect to the input signal; and first, second and third resonators coupled respectively to the input port, the first output port and the second output port.