Compact 3-D Printed Rectangular Waveguide Diplexer With Wide Stopband Response

This paper presents compact, 3-D printed rectangular waveguide diplexer with wide stopband response. The two channel filters are designed by using miniaturized TM cavities with wide stopband response achieved using the recently proposed spurious self-suppression method. The channel filters are then connected using a ridged waveguide T-junction to achieve diplexing operation. Moreover, presence of TZs in TM structures allows the achievement of better isolation between the two channels. The two channels have a center frequency of 9.6 GHz and 10 GHz respectively, with a FBW of approximately 2%. Both the channels have wide spurious free ranges up to 20 GHz. Additive Manufacturing (AM) 3-D printing technology is exploited to manufacture the proposed diplexer prototype. Measured results are in good agreement with the simulation.