Patent ID: 8125296

Claim:
A filter arrangement at an antenna end of a radio device using frequency division duplex, the antenna end including a divider with isolated output branches for dividing a radio transmitting signal coming from a power amplifier to antennas which radiate in different sectors, the filter arrangement comprising: a separate duplex filter for each of said antennas comprising a separate transmitting filter and a receiving filter, an output of said separate transmitting filter and input of said receiving filter being coupled to a respective one of said antennas, and one of said output branches being coupled to an input of a respective one of the separate transmitting filters; and a shared transmitting filter for the antennas, comprising a bandpass part and a low-pass part connected in series, an input of the shared transmitting filter being coupled to a power amplifier and an output of the shared transmitting filter being coupled to an input of said divider so as to simplify said separate transmitting filters and to reduce the space required for the antenna end of the radio device.