A band combining filter for passing signals in a communications band includes a plurality of cascaded directional filters. Each directional filter has at least two inputs and at least two outputs. The nth directional filter is arranged such that output signals O1 and O2 from the first and second outputs are related to input signals I1, I2 to the first and second inputs by the relation ( O 1 O 2 ) = ( R n ⁢ ⁢ 1 T n ⁢ ⁢ 2 T n ⁢ ⁢ 1 R n ⁢ ⁢ 2 ) ⁢ ( I 1 I 2 ) with R and T being reflection and transmission functions respectively. The directional filters are connected in a cascade with the first and second inputs of the nth directional filter being connected to the first and second outputs of the (n−1)th directional filter respectively in the cascade. At least one of the reflection functions Rn overlaps with the corresponding reflection function Rn−1 within the communication band but is different thereto.