Abstract: A filter structure has a frame carrying a filter compartment that holds first and second waveguide filters (F1H, F2H; F1L, F2L). The filter compartment is rotatable a predetermined angle around a rotation axis (AV) relative to the frame so as to either engage the first waveguide filter (F1H, F2H) or the second waveguide filter (F1L, F2L) in a waveguide conduit, thus rendering the waveguide conduit adapted for forwarding radio-frequency signals at a higher band or a lower band respectively. Consequently, the filter structure is suitable for inclusion in a dual-band radio terminal for communication with spacecrafts via an antenna unit exchanging radio-frequency signals bidirectionally with the spacecrafts.