Proceeding of The 6
th
National Radar Seminar And The first International Conference On Radar, Antenna, Microwave, Electronics And Telecommunications ICRAMET 2012
Bali, April 23-24, 2012
96
Design And Realization of a Low Cost Two-Way Wilkinson Power Divider at Intermediate Frequency for a RADAR System
Taufiqqurrachman and Hana Arisesa
Research Center for Electronics and Telecommunication Indonesian Institute of Sciencies LIPI
LIPI Campus, Sangkuriang Street, Building 20 - 4th floors, Cisitu Bandung – Indonesia 40135
Phone: +62-250-4660 Fax: +62-250-4659 Email:
taufiqqurrachmangmail.com
Abstract—This paper
presents analysis
and design
narrowband two-way Conventional Wilkinson power divider. The design employed common lumped element that much
easier to realize. This Wilkinson power divider designed at 456 MHz for use in IF RADAR System. The practical fabrication
implemented on FR4 substrate. The VSWR for all port for both dividers is better than 1.3:1, insertion loss is less than 0.6
dB and 25 dB of isolation is achived. The proposed divider has the narrow bandwidth, 200 MHz. It was found that the
Wilkinson power dividers can’t perform well with simulation values. However, this problem could be solved by fine tuning
capacitor components.
Keywords-Power Divider; FR4; Two-way splitter
I. INTRODUCTION
Power dividers are widely used in RFmicrowave system. Some of their application mainly used in
amplifiers, antenna systems, mixers, and modulators. Among all sorts of divider, the Wilkinson topology shows
the basic concept of n-way power dividing by its simple structure [1]. Wilkinson power divider matches all input
and output ports simultaneously and provides a good isolation between the output ports for the power divider.
They can handle arbitrary power levels from input to output ports [2]. Two way power divider is the most common
application of wilkinson power divider. Many papers have discussed various types of wilkinson power divider design
[1-3].
Figure 1. Equivalent two-way Wilkinson power divider circuit.
Power divider usually using an λ4 transmission line at the design center frequency and consists two
segments with characteristic impedance √2Z
o
with the isolation resistor 2Z
o
Figure 1. In particular, a quarter-wave line at a frequency fo,
with characteristic impedance Z
o
, can be replaced for a “Pi” LC equivalent network [4], by converting Z
o
to the Inductor and Capacitor equivalent respectively Figure
2, by the following formulas : C
p
= X
c
= 12pif
o
Z
o
1 L
s
= X
l
= Z
o
2pif
o
2
Figure 2. Equivalent quarterwave transmission lines to their lumped element.
In this paper, a design and realization of two-way wilkinson power divider at f
o
= 456 Mhz, are presented. The divider has been fabricated using FR4 substrate.
The results including S-parameter measurement, power division, isolation, reflection coefficient, and VSWR
will be discussed at the end.
II. IMPLEMENTATION DESIGN
Refering to the equations 1 and 2, its possible to design the equivalent lumped element for this project.
Characteristic impedance Z
o
= 50 Ohm, so L
s
and C
p
could be calculated easly by employing the formulas. All the results for inductance and capasitance values are
listed in Table 1.
Proceeding of The 6
th
National Radar Seminar And The first International Conference On Radar, Antenna, Microwave, Electronics And Telecommunications ICRAMET 2012
Bali, April 23-24, 2012
97
Table 1. All inductance and capasitance values from calculation.
Components Value
Unit
Ls 24.69
nH Cp
4.936 pF
R 100
Ohm
Applying the values of lumped components to the schematic circuits is shown on Figure 3. In order to
know the performance of the proposed circuit. The FR4 substrate is used to implement the design, with
thickness of 0.8 mm and relative dielectric constant ε
r
4.4. However, implementation these values into the
circuit analysis, does not meet the goal. Therefore optimisation is performed during the simulation to get
the good result. Variabel capacitor is used in this design where we can do tuning at measurement stage.
Figure 3. Schematic circuit of proposed Wilkinson power divider.
III. SIMULATION and MEASUREMENT
