ISSN: 1693-6930
TELKOMNIKA Vol. 15, No. 1, March 2017 : 227
– 237 230
BPF by using pole N=10 is produces a bandwidth about 3 GHz shown by the value under -15dB -15dB is depicted on Figure 3. The cutoff of filter -3dB down at the frequency
of 9.0926 GHz to 9.5255 GHz and the bandwidth of passband is 432.9 MHz. The value of return loss on each port S
11
-S
22
at 9.3GHz is -20,4669 dB. The proposed design of bpf module with N=14 is depicted in Figure 4. The values of
parameter in this filter design as follows: S
t
= 0.25 mm; S
t1
= 0.25 mm; y
1
= 0.25 mm; y
2
= 0.2 mm; y
3
= 0.4 mm; y
4
= 0.25 mm; a = 3.343 mm; b = 7.9 mm; w
s
= 1.55 mm; s
s
= 0.4 mm; ᴓ r =
0.5 mm; w
st
= 2.3 mm; l
st
=3.25 mm; w = 12.75 mm; l
= 14.386 mm; h = 0.51 mm.
Figure 5. Simulation Result S-Parameter of Band Pass Filter N=14 BPF by using pole N=14 is produces a bandwidth about 2.2332 GHz shown by the
value under -15dB -15dB is depicted on Figure 5. The cutoff of filter -3dB down at the frequency of 9.1795 GHz to 9.463 GHz and the bandwidth of passband is 283.5 MHz. The value
of return loss on each port S
11
-S
22
at 9.3GHz is -16.16651 dB. BPF with different pole N = 10 and 14 produce a different characteristics, the more of
poles N is smaller bandwidth, this can be proved BPF with N = 14, resulting smaller bandwidth compared to BPF with N = 10. In the compact integration module, BPF used pole N = 10 in
terms of the return loss is better than BPF with pole N = 14
2.2. The 2-way Wilkinson Power Divider Design and Simulation
The 2-way Wilkinson Power Divider WPD usually work at quarter-wavelength transmission line
λg4 section at the design center frequency and Wilkinson power consists of two quarter-wavelength line segments at the center frequency f
c
with characteristic impedance Z
o
, and a 2Z
o
lumped resistor connected between the output ports [11]. From the explanation can be seen that the type of power divider has four sections as follows [12]:
1. Input port 2. Quarter-wave transformers
3. Isolation resistors 4. Output ports
Figure 6. The Wilkinson Power Divider; a An Equal-Split Wilkinson Power Divider in Microstrip form, b Equivalent Transmission Line Circuit
TELKOMNIKA ISSN: 1693-6930
Compact Power Divider Integrated with Coupler a nd Microstrip Cavity… Yudi Yulius Maulana
231 The smallest insertion loss result depends on designing of the width of λg4 section W
at frequency center f
c
. Based on Figure 6, the 2-way WPD has some ideal parameters that can be implemented into a microstrip transmission line. We designed the 2-way WPD with 9.3 GHZ
Fc, Z
o
= 50Ω and deploy isolation resistor R1= 100 Ω between 2 port output.
a b
Figure 7. a Layout for Simulation 2-way WPD, b Field Simulation result The design of 2-Way WPD depicted in Figure 7. The values of parameter in this filter
design as follows: S
w1
= 5.5 mm; S
w2
= 6 mm; S
w3
= 2 mm; l
st
= 0.9 mm; R
1
= 4.8 mm; R
w
= 8 mm; S
l1
= 1.5 mm, w = 14 mm; l
= 29.6 mm; h = 0.51 mm.
Figure 8. Simulation Result Return Loss of 2-Way WPDS
11
, S
22
, S
33
The result of this simulation contains graphs of the return loss, insertion loss and isolation of the proposed design of 2-way WPD. From the simulation result, the input S
11
red line and output port S
22
green line S
33
blue line depicted in Figure 8 have a good return loss is less than -28 dB this is indicating less than 0.158 of the power is reflected back. Figure 9
show the bandwidth of 2-way WPD is about 2 GHz categorized as wide band. These specifications do not meet to apply on our radar, which requires a bandwidth of 60-150 MHz at
Fc 9.3 GHz therefore the output port needs to add a narrowband BPF.
Figure 9 show the insertion loss, reverse transmission line S
12
red line S
13
green line showed that this device as combiner have equal power with transmission loss about -3.183 dB,
it’s indicate the signal power will be transmitted only have a loss approximately 0.183 dB. The graph also show for forward transmission line S
21
blue line S
31
yellow line showed that this device as power divider have equal power with transmission loss about -3.192dB, its indicate
the signal power will be transmitted only have a loss approximately 0.192 dB from ideal split
ISSN: 1693-6930
TELKOMNIKA Vol. 15, No. 1, March 2017 : 227
– 237 232
power of 2-Way WPD is. This 2 Way WPD have a good insertion loss refers to calculation 10 log 2 the number of ports divided.
Figure 9. Simulation Result Insertion Loss S
12
, S
13
, S
21
, S
31
Figure 10. Simulation Result Isolation between 2 ports S
23
,S
32
Figure 10 show the isolation between the both output ports S
23
red line S
32
green line has good isolations about -33.828 dB, this value is better than the desired planning that is -
20dB. The isolation value of the proposed design is enough to prevent cross-talk between the both output ports.
2.3. Directional Coupler Design and Simulation
