Multiphysics design of a spatial combiner predisposed for thermo-mechanically affected operation

Abstract

This paper describes the design based on a Multiphysics simulation for a waveguide X-Band Fin Taper (FT) Spatial Power Combiner. The proposed device uses Fin Lines to microstrip transition (FLuS) to convert the energy from a rectangular waveguide (WG) TE₁₀ fundamental mode to a microstrip (μS) transmission line (TL) quasi-TEM (q-TEM) mode, in order to be amplified by Solid-State Power Amplifiers. An alteration of the electromagnetic behavior can be produced by the temperature increase and the geometrical displacement induced by the thermal expansion of the structure due to the power dissipation of the MMIC amplifiers. A proper multiphysics model is proposed to select materials and shapes of the probes and their support (carrier), considering the thermo-mechanical operative condition. A virtual prototyping technique is proposed: electric field and S-parameters’ computation in such critical conditions are shown. The proposed study has allowed for the proper thermo-mechanical design for such amplifiers; hence, best materials and technologies have been chosen.

Keywords:

• computational electromagnetics
• FEM methods
• multiphysics modeling
• power amplifiers
• spatial power combiners
• waveguides