The present invention relates to a tunable microwave arrangement (100) comprising a waveguide arrangement and tuning elements comprising a number of varactors for tuning an electromagnetic signal input to the waveguide arrangement. It comprises a substrate (1), a layered structure (20) comprising at least two conducting layers (2,3) and at least one dielectric layer (4) which are arranged in an alternating manner. The layered structure is arranged on the substrate (1) such that a first of said conducting layers (2) is closest to the substrate (1). It also comprises at least one surface mounted waveguide (5), a second of the conducting layers (3), most distant from the substrate, being adapted to form a wall of the surface mounted waveguide (5), which wall incorporates said tuning elements which are arranged to enable control of surface currents generated in said wall, hence loading the waveguide (5) with a tunable, controllable impedance.