Appendix 3.2 Design with Parasitics
In this step, the PCB and element parasitics and losses are introduced. As with the ladder two-element match design example, the
same 0402 SMD series from Murata (LQP15MN film type inductors and GRM1555 type capacitors) is used with the equivalent circuits
given in
Figure 3.5 Reference Planes with Real SMD Elements on page 10
. The applied layout is also the same, and, thus, the PCB
parasitics shown in
Figure 3.6 Estimation of PCB Layout Parasitics on page 10
. are used. The figure below shows the tuned ladder
four-element match locus and schematic with parasitics. The endpoint at the IC side (denoted by TP11 in the Smith chart and by Zin in
the schematic) is very close to the targeted optimum (Zload_opt = ~23 + j11.5 Ω).
Figure 3.2. Ladder 4-Element Match Tuning with SMD Element and PCB Parasitics
Optionally, EM simulations can be done for better accuracy, but the SMD element values of the schematic of Figure C2 is already a
good starting point for the bench tuning.
AN930: EFR32 2.4 GHz Matching Guide
2.4 GHz Ladder 4-element RF Matching Design Steps
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