| Horns |
Designs using FEAMAAS has used a Finite Element Analysis package to investigate and design many complex components and antennas which cannot be treated by other methods. Examples include quadridged horns, printed anetnnas on curved structures, waveguide windows using a variety of dielectrics, complexer side-entry couplers which operate over a broad bandwidth. A typical example is compared with mode- matching results below. The requirement was for a diplexer to separate out two bands in ATMS, one at 23.8 GHz and the second at 31.4 GHz. The inputs and outputs are in standard rectangular waveguide. This component was initially designed using a mode-matching program, RECTGEN, which can deal with rectangular waveguide. However a transition between circular and rectangular waveguide was required to mate the output from a circular corrugated horn to the diplexer and this, being mixed mdoe, was designed using a special mode-matching program, RTCC. Mode-matching cannot handle the combination of the two componet. the componets were therfore modelled separately using the FEA program and then the two components were mated together.The consistency between the mode-matching programs and the FEA program could therefore be checked.The agreement was found to be excellent even at levels below -50 dB. Figure 1 shows the geometry of the final version of the diplexer and Figures 2 to 4 compare the predicted results using both methods. FIGURE 1 Final version of the Diplexer generated using SOLIDWORKS
FIGURE 2 Return Loss of input port
FIGURE 3 Transmission Loss between the input port and the output port for 31.4 GHz
FIGURE 4 Transmission Loss between input port and output port for 23.4 GHz channel
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