Design of a BAW Quadplexer Module Using AWR Software
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As shown in the Figure 9, the BPF for the B3 band at 1.8GHz has excellent return loss (below 20dB) and transmission zero (band
rejection) at the B7 band (2.6GHz), which will provide satisfactory isolation for the diplexer. Circuit elements and variables of the
B7 LTE band BPF are shown in Figure 10. The two filters have similar circuit layout with different dimensions.
Figure 10: Circuit elements and variables of the B7 band BPF
The simulation results for the B7 band BPF are shown in Figure 11. Transition zero is adjusted to be in the counter-frequency
band in order to have favorable isolation in the diplexer.
Figure 11: S-parameters of the EM simulation results for the B7 BPF
Looking at the insertion losses of the both filters, it can be seen that the signal has very little attenuation over the bands and
that the reflection of the filter has been kept to a minimum. The next step was to combine the two BPFs with a T-junction in
order to create a diplexer.
