RF Electronics Chapter 7: RF Filters Page 267
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
AXIEM uses less mesh elements and models the shape of the bend more accurately than
EMSight. Requiring more mesh elements results in a slower simulation. Using a cell size
of 0.1 mm and a typical computer, both circuits of figure 7.88 and 7.89 take 25 minutes
to complete using AXIEM, but the circuit of figure 7.88 alone took more than 2 days to
complete using EMSight and gave several warnings about convergence, thus producing
an incorrect result. EMSight will be more accurate than AXIEM to use on simple
couplers, like the one shown in figures 4.39 to 4.45.
Figure 7.92. 2D Layout of hairpin filter of figure 7.89 with mesh shown.
Figure 7.93. Close up of meshing applied by AXIEM (Left) and EMSight (Right).
For the filter design and optimisation, circuit simulation with E
r
=3.38 and E
rNom
=3.38 was
used. Rogers in their datasheet [16] for R04003 specify E
r
=3.38 and suggest that E
r
=
3.55 is used for simulation. The circuit and EM simulation shown in figures 7.51 and 7.52
used E
r
= 3.38 for all simulations and the EM simulations are very close to the measured
results. For the filter of figure 7.83, the circuit simulation shown in figures 7.94 and 7.95
with E
r
=3.38 gives the desired 1 GHz centre frequency and E
r
= 3.53 gives the desired
1 GHz centre frequency for the EM simulation.
RF Electronics: Design and Simulation
267 www.cadence.com/go/awr
