AWR Application Notes

Design of a BAW Quadplexer Module Using AWR Software 5 www.cadence.com/go/awr The line width and length of the microstrip transmission lines were calculated according to the electrical length of the quarter-wave length for a Rogers Duroid 6010 substrate with a dielectric constant of 10.8 and thickness of 0.635mm. The calculations were made using the TX-LINE transmission-line calculator in AWR Microwave Office software. Two identical stepped-impedance open stubs were used in order to increase the stopband rejection ratio. Figure 8 shows the filter param- eters of BPF for the B3 band with center frequency of 1.8GHz in AWR Microwave Office software. Figure 8: Filter parameters of the BPF for the B3 LTE band After the element variables were calculated and estimated, the next step was simulation. Two simulation approaches were considered. One is a linear simulation in which overall system parameters are calculated by separately cascading the S-parameters of each of the elements. This simulation provides insight about the circuit performance and matching charac- teristics of the elements. The second approach is to use electromagnetic (EM) simulation to analyze overall circuit behavior, validating the accuracy of the individual transmission line elements and their use in this modeling effort, and addressing any non-modeled parasitics such as coupling effects. Both approaches account for substrate features such as height of the substrate, height of the open space above the layout, and non-idealities of the conductor. After initially developing the circuit parameters (line widths, lengths) using the schemat- ic-based transmission line elements, it was decided that the EM simulation approach would provide better accuracy and insight about circuit behavior after manufacturing. Figure 9 shows the S-parameters of the B3 LTE BPF The S11 parameters show the reflection loss as well as the matching characteristics. The S21 parameters show the insertion loss over frequency in which some signals are attenuated more than others due to the intended filtering. Figure 9: S-parameter results of the EM simulation for the B3 LTE BPF

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