Design of a BAW Quadplexer Module Using AWR Software
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Quadplexer
Before combining the BAW duplexer to a common node via the diplexer, it was necessary to evaluate the S-parameters of the
BAW duplexers. Figure 18 (left) shows the S-parameters of the duplexer for the B3 LTE band. The S-parameters of the module
are the same as the datasheet.
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Figure 18 (right) shows the S-parameters of the B7 LTE band duplexer. The S-parameters of
the module are the same as the datasheet.
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Figure 18: S11 and S32 parameters of the BAW duplexer (left) and S-parameters of the band 7 BAW duplexer (right)
Because the BAW filters were matched to 50Ω, the diplexer and duplexer were easily connected as a cascade structure. The
small packet dimensions and pad width needed additional attention to the connection of the BPF`s 4mm-wide transmission
line to the BAW duplexer`s 0.35mm-wide pad. In order to eliminate mismatch of these transmission lines, tapered microstrip
transmission lines were used.
Because the circuit was designed to be small and compact, the SubMiniature version A (SMA) connectors of the circuit were
placed as close together as possible. The circuit had dimensions of 5x4cm length and width. After the circuit elements were
placed in the layout, an EM simulation was performed. Figure 19 (left) shows the simulation results for reflection loss param-
eters S11, S22, S33, S44, and S55 scattering parameters. It can be seen that the reflection parameters of system are around
-10dB, which is an acceptable range for reflection loss. Figure 19 (right) shows the simulation results of quadplexer for
insertion loss. It can be seen that the insertion loss of the diplexer has minimal effect on insertion loss of the overall system.
Figure 19: Simulation results of the quadplexer for reflection loss (left) and insertion loss (right)
