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Postgraduate YPEC 2021

PG04-Investigation of SAW Filter with Interdigital Transducer Parametric Variation by FEM Simulation and In-House Fabrication

SAW filter is widely used in wireless communication, especially in 5G and IoT applications. It is an important passive component in this wireless front-end circuit due to its compact size and high-quality factor. Since it shares the same fabrication processes with the integrated circuit’s industry, the SAW filters can be massively produced to further reduce the cost. In this project, evaluation of the in-house design and fabrication of SAW filter was studied. Detailed effect of interdigital transducers (IDTs) variation was investigated by FEM simulation. The parametric variation includes the presence of reflectors, IDT’s length, separation of ports, the number of reflectors and IDTs per port. The SAW filters were fabricated in the University Research Facility in Material Characterization and Device Fabrication (UMF) in The Hong Kong Polytechnic University (PolyU), which is the first in-house fabricated RF component. The capability of investigating the detailed SAW features has been demonstrated. The best fabricated SAW filter gives lower than 3 dB of insertion loss and more than 10 dB of return loss at 480 MHz without any external lumped elements at the ports for matching used in traditional SAW filter’s circuit.