Characterization of waveguide slots using full wave EM analysis software HFSS

In this paper design curves have been investigated for broad wall longitudinal radiating slot and centered-inclined coupling slot in a Ku-band waveguide WR51 using an FEM based full wave EM analysis software, HFSS. These curves have application in the design of waveguide slot arrays. Two waveguide-fed planar slot arrays have been designed using these curves and HFSS was used to simulate the performances of these array antennas before experimental testing. Measured gain pattern and input return loss of the arrays are in good agreement with those simulated by HFSS. The performance of these arrays validates the design curves and also depicts the power of HFSS. In waveguide-fed planar slot arrays designed in standard waveguide WR51 the coupling slots could not be spaced lambda_g/2 apart because of physical constraints; which limits the bandwidth of the array antenna. Therefore, for larger bandwidth applications it is necessary to overcome this physical constraint. Accurate centre frequency and enhanced bandwidth has been achieved by designing an array antenna in a custom waveguide.