I want to simulate this model, which consist of two horn antennas ,two lenses , wire grid embedded into dielectric material for frequency range 76 to 81 GHz , I tried the time domain solver , as the small dimension for the wires is in part of mm and the lens biggest dimension is 180mm then the number of mesh cells are too large in range of 500 millions which is take too long time for simulation and I am not sure if this solver is the best solution for also giving accurate results

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