Optimization of a small and lightweight antenna for handheld RFID reader

Mauro Poian - EnginSoft

CHALLENGE - The successful integration of two softwares is presented in this work, with the demonstration of two case studies. The aim of the first case is to optimize a compact, low cost, circularly polarized antenna for UHF RFID applications. Challenges include the development of a completely automated, time-saving, objective-oriented procedure. ​The second case involves a coax to wave guide model: EM and Thermal in order to minimize voltage breakdown and peak temperature.

SOLUTION - The parametric model, developed into CST Microwave Studio 2016, has been integrated into the modeFRONTIER optimization platform. The single CST simulation takes about 80 minutes on WS machine with 4 processors and 20 GB RAM. The entire loop of optimization takes about 10 days using the same WS. Process integration is the automatic generation of Uniform Latin Hypercube DOE, optimization by genetic algorithm MOGA–II, graphical post-processing and optimal trade-off solutions. In the second case, high power coax to waveguide optimization,​​ a multidisciplinary scenario is entirely modeled inside CST software by taking into account the electromagnetic and thermal field. 

BENEFITS - In the first case a compact, low-profile, low-cost, dual-band circularly polarized antenna has been designed, which is suitable to be integrated in the PCB of a portable reader. Despite limited antenna volume, good performances in terms of both axial ratio and return loss have been obtained. In the waveguide optimization case, the seamless integration between modeFRONTIER and CST allows easy coupling of the two softwares. Overall, in the first case, modeFRONTIER helped meet the design targets, whereas in the second case it identified the best compromise between the most important requirements.