RESULTS AND ANALYSIS
Simulation Results
The designed Koch and Sierpinski
fractal-shaped microstrip stepped-impedance low-pass filters with different
iteration orders are simulated using
the finite-element-method (
FEM)-based software Ansoft HFSS 10.0; the
simulated frequency responses are
shown in Figure 3.
As can be seen, the two kinds of
fractal-shaped low-pass filters show
great passband performance enhance-
ment abilities. The simulation results
of these filters are summarized in
Table 2, where F is the fractal shape, Iter
is the iteration number, MRL is the
maximum return loss in the passband
in dB, CF is the cut-off frequency in
GHz, SL is the selectivity17 in dB/Hz,
2H-IL is the second harmonic insertion loss in dB and 2H-F is the operating frequency corresponding to 2H-IL.
The maximum return-loss level of the
passband of the Koch fractal-shaped
microstrip stepped-impedance low-
pass filters decreased from - 19. 8 dB
for K0, to a value below - 30 dB for K2,
and the maximum return-loss level of
the passband of the Sierpinski fractal-
0
MAGNITUDE (dB)
– 5
– 10
– 15
– 20
– 25
– 30
– 35
– 40
– 45
– 50
– 55 10 98765 43210
S21
S11
K0 K1 K2
FREQUENCY (GHz)
SATCOM Test Equipment
(a)
V-SAT earth station development
Mobile terminal testing
Payload communications testing
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0
MAGNITUDE (dB)
– 5
– 10
– 15
– 20
– 25
– 30
– 35
– 40
– 45
– 50 10 98765 43210
S21
S11
S0 S1 S2
FREQUENCY (GHz)
(b)
s Fig. 3 Simulated response of fractal-shaped stepped-impedance low-pass filters
with different iteration orders; (a) Koch and
(b) Sierpinski.
Satellite
RF Link emulation
and link budget testing
for payload and terminal
development. System allows
phase continuous Doppler,
delay, path loss, phase shift and
flat fading to be independently
programmed for each channel.
Multiple channels permits
satellite or earthstation handoff
emulation for full constellation
testing.
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dBm, LLC
32A Spruce Street ; Oakland, NJ 07436
Tel (201) 677-0008 ; Fax (201) 677-9444
www.dbmcorp.com
s Fig. 4 Prototypes of the Koch and
Sierpinski fractal-shaped microstrip stepped-impedance low-pass filters.
