The application discloses a C-band tuning-free
duplexer and belongs to the technical field of
microwave filters. The tuning-free
duplexer comprises an upper conductor and a lower conductor, and the upper conductor and the lower conductor are buckled one above the other to form a
waveguide cavity. The upper conductor is provided with a combining port in the middle of the top, and the lower conductor is provided with a low-frequency input / output port and a high-frequency input / output port at the bottom. The
waveguide cavity from the low-frequency input / output port to the combining port constitutes a low-end filter, and the
waveguide cavity from the high-frequency input / output port to the combining port constitutes a high-end filter. The main bodies of the high-end filter and the low-end filter are both a plurality of waveguide resonant cavities arranged along a straight line, the middle positions of each waveguide
resonant cavity are provided with cavity loading, and adjacent waveguide resonant cavities are connected through inter-cavity
coupling. The tuning-free
duplexer adopts a symmetrical structure and a center loading mode, realizes tuning-free
assembly, has the characteristics of high power
bearing capacity,
low transmission loss and excellent
signal isolation, and is suitable for a C-band communication
system.