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A clamped cubic spline profile taper of an air-filled substrate integrated waveguide (SIW) transition was optimized to search for the optimal design of taper in this paper. The optimization technique involved a combination of the multi-objective genetic algorithm (MOGA) and full-wave analysis of the waveguide. The data from the return and transmission losses provides a basis for the optimization of the transition tapers design. The simulation results show the efficacy of our proposed strategy, where the optimal taper geometry yields an improvement of the return loss while maintaining its original transmission loss at Ka-band (26–40 GHz) frequencies.

There are lots of companies manufacturing electronic components that have commonly used the Surface Mount Technology printing process. However, the temperature of solder paste printing on the Printed Circuit Board can influence the presence of defects in Surface Mount Technology. In this paper, the experiment called Surface Mount Technology printing is built and tested to characterize the temperature of solder pastes in order to prevent the electronic waste and rejection rate of the malfunctioning electronics due to poor soldering. The microstructures of solder paste on printed circuit board and copper substrate are inspected under Scanning Electron Microscopy. It is focused on two parameters that affect the performance of a printed circuit board, which includes the filling areas of solder paste and the distance between ball grid arrays. From the experiment and analysis results, the filling area decreases as the temperature increases during the Surface Mount Technology printing process. In short, when the temperature of SAC305 increases, the viscosity and filling areas decreases. In fact, SAC305 gave the second rank of smallest area (18.86%) and distance (43.43%) after SAC307. The average area and distance are fair enough for the solder to hold the component placement, unlike SAC307 which likely causes tombstone.

No abstract

The transitions in an air-filled substrate-integrated waveguide (SIW) are studied here for millimetre-wave applications. A good design of an air-filled SIW (AFSIW) must allow for minimum losses in its interconnects between the air-filled and dielectric-filled regions of the SIW. This paper assesses the influence of the geometry of transition taper in an AFSIW on the return and insertion losses using full-wave analysis of a complete AFSIW structure. The data from the return and transmission losses provide a basis for the optimisation of the design of the transition tapers. The optimisation approach uses the multi-objective genetic algorithm (GA) with full-wave analysis to find an optimum profile of the transition. Defining the profile of the transition taper with a clamped cubic spline as a phenotype, the developed procedure shows that further losses are possible within the prescribed frequency bands. Furthermore, the length of the transition taper can be significantly reduced while maintaining an optimal quality of signal transmission in the transition. The simulation results show the efficacy of the proposed strategy where the optimal taper geometry is shown to provide a wider band of operating frequencies with lower return loss compared to a more established taper geometry.