Abstract: An amplification circuit for a wireless base station is provided. The amplification circuit includes a first port adapted to communicate signals to and from an antenna and a second port adapted to communicate signals to and from a base station. The amplification circuit further includes a first path and a second path with each path coupled between the first and second ports. The first path includes at least one bandpass filter and an amplifier that pass and amplify upstream signals in a first frequency band. The second path includes a filter that stops upstream signals in the first frequency band and passes upstream signals in at least a second frequency band and downstream signals in at least third and fourth frequency bands.

Abstract: The invention relates to a filter and a frequency tuning element. The filter comprises a shell construction (2a to 2d) of conductive material with at least one section (14 to 16) and in the shell construction (2a to 2d) at least one resonator (17 to 19) of conductive material in said at least one section (14 to 16) for forming at least one resonance circuit (11 to 13). In the filter (1) the resonator (18) comprises as its extreme ends a base (18a) and a second end (18b), in said filter (1) the base (18a) of the resonator (18) being fastened to the shell construction (2a to 2d) and the second end (18b) of the resonator (18) being directed elsewhere towards the shell construction (2a to 2d) at a distance therefrom, the resonator (18) comprising a means (32) which directs its surface towards the shell construction (2a to 2d) and increases the cross-sectional area of the resonator to increase the capacitance between the resonator (18) and the shell construction (2a to 2d).