Patent ID: 6879222

Claim:
A duplexing communication signal filter for connection to an antenna, a transmitter and a receiver, the signal filter suitable for filtering an incoming signal from the antenna to the receiver and for filtering an outgoing signal from the transmitter to the antenna, the filter comprising: a substantially U-shaped core of dielectric material including a transmit arm, a receive arm and a base portion joining the transmit arm to the receive arm, each arm having an inwardly facing surface and an outwardly facing surface and each arm defining a series of through-holes, each through-hole extending through the arm between an opening at the inwardly facing surface and an opening at the outwardly facing surface; and a pattern of metallized and unmetallized areas on the core including, a wide area of metallization, a first unmetallized area surrounding a plurality of the through-hole openings on the outwardly facing surface of the transmit arm, a second unmetallized area surrounding a plurality of the through-hole openings on the outwardly facing surface of the receive arm, a transmitter pad metallized area on the transmit arm for receiving the outgoing signal, a receiver pad metallized area on the receive arm for providing the incoming signal, an antenna pad metallized area on the base portion for receiving the incoming signal and outputting the outgoing signal, a bridge metallized area extending between the transmit arm and the receive arm, and a bridge through-hole extending between the transmit arm outwardly facing surface and the receive arm outwardly facing surface, the bridge through-hole having side walls and the bridge metallized area being present on the side walls of the bridge through-hole.