Design of SMA 50 Ω Load Using 3D EM Field Simulator: Comparison with Reality

The subject of this paper is to provide a comparison of 3D EM field simulation results of 0603 size SMD resistors with corresponding real data obtained by precise vector measurements. The simulated results were obtained by 3D EM field simulator CST Microwave Studio with time-domain solver. The comparison is shown on a design of an optimized 50 Omega load composed of a common SMA flange connector and a set of 0603 size SMD resistors. The resistors are soldered between the inner conductor of the coaxial SMA connector and the flange. Several arrangements of the SMD resistors ranging from single-resistor arrangement to four-resistor pattern as well as different orientation of the resistive layer of the SMD resistors are discussed. Step discontinuity of the inner conductor of a real SMA connector is subsequently also involved in 3D EM field simulation and these results are compared with precise vector measurements.