In this research, a satellite on the move DBS receiver has been designed and implemented based on Radial Line Slot Array (RLSA) antenna which operates at Ku band. This antenna is implemented with brass as conductor and air (er ≈ 1) as dielectric material and has eight concentric array slot pairs to achieve conical beam, better gain and wider frequency bandwith compared to Makoto Ando model. From the simulation and measurement results we can see that our RLSA prototype has passed the technical specifications . This antenna has conical beam, with 14.22 dBi at 12.0 GHz, operational frequency bandwidth about 1.7 GHz and axial ratio about 3.79 dB. For enhancing the RLSA prototype, we also have developed the 2 x 2 planar RLSA antena which has about 6 dB additional gain. Moreover, this low cost implementation of RLSA antenna will decrese the CAPEX of DBS deployment at public trains, ships and buses in Indonesia

1. Design and Implementation of RSLA Antenna
for Mobile DBS Application
in Ku-Band Downlink Direction
By :
1) Dr.Ir.Joko Suryana
2)Dimas Budiarto Kusuma, ST
Radio Telecommunication and Microwave Laboratory
School of Electrical Engineering and Informatics,ITB
Jl Ganesa 10 Bandung 40132, Indonesia

2. Overview
• In this research, a satellite on the move DBS receiver has been
designed and implemented based on Radial Line Slot Array (RLSA)
antenna which operates at Ku band.
• This antenna is implemented with brass as conductor and air (er ≈ 1) as
dielectric material and has eight concentric array slot pairs to achieve conical
beam, better gain and wider frequency bandwith compared to Makoto Ando
model.
• From the simulation and measurement results we can see that our
RLSA prototype has passed the technical specifications .
• This antenna has conical beam, with 14.22 dBi at 12.0 GHz, operational
frequency bandwidth about 1.7 GHz and axial ratio about 3.79 dB.

3. Background
SOTM DBS
• The provision of DBS reception (pay TV) in
moving vehicles is now increasing. The need
for satellite-based pay TV services on mobile
vehicles such as ships, aircraft, trains and
buses is perceived to be popular.
• In 2014, the number of Pay TV subscribers
reached about 3 million as fixed DBS
subscribers

4. Background
• Previously, mobile satellite communications
antenna uses a parabolic dish mounted on a
stabilized platform driven by two motors.
Despite giving a pretty good gain, the use of
parabolic dishes on land, sea, and air vehicles is
constrained by air resistance on the parabolic
dish and its heavy mass. A very good quality
motor control system is required to support the
antenna mechanism, which is obviously very
expensive.
• Another solution is thin and flat microstrip
phased-array antenna system which will allow
the vehicle to keep moving aerodynamically,
and the continuity of communication links is still
maintained even when the vehicle is moving or
doing some maneuvers, but we still need to
have mechanical steering on azimuth direction.

5. Objectives
• The objective of this research is to design
and implement a low-cost DBS reception
antenna at Ku-band which has good
stability to receive satellite signal while
on the move.
• This DBS receiver antenna requires to
have conical beam which its main beam
direction always point to the satellite
position during on move.
• No more mechanical beam steering systems
• No need electronical beam steering systems

6. Methods
Technical Specs
• In this research, the target design and
prototype is used for SOTM (satellite on the
move) DBS receiver which operates at Ku-
band for Indonesia area.
• The DBS receiver should has capability to
receive satellite signals at 17 – 22° for
Indonesian Ku-band satellites reception
(such as Palapa D). The minimal gain at 12
GHz is more than 9 dBi and has small form
factor.
• The antenna should also has conical beam
pattern with bandwidth > 1 GHz.
• The detail of technical specifications can be
seen as Table I

7. Methods
Structure
• The RLSA antenna is based on Makoto Ando
model
• RLSA antenna consists of two conductor plates
which parallel to each other.
• The bottom plate conductor is the ground plane
and the upper plate is the radiator.
• The upper and bottom plate is short circuited in
this design.
• This RLSA antenna has some concentric slot
pairs of antenna on its upper plate.
• The slot is designed perpendicular to each other to
get the elliptical polarization.
• Concentric array design is combined with coaxial
mode excitation to get the conical beam radiation .

8. Results :
• Single element RLSA antenna design

9. Results :
• The implemented single element RLSA antenna
• This RLSA antenna has -25.335 dB as the lowest return loss value at 11.8 GHz. At 12.0 GHz, the measured return
loss was -21.377 dB. Bandwidth for < -10 dB return loss was measured around 1.7 GHz or 14.17% in the
frequency region 10.8 GHz – 12.5 GHz.The implemented RLSA has conical radiation pattern as expected and its
main lobe direction is at 18°. The measured gain was 14.22 dBi at 12.0 GHz.
Measured S11 Radiation Pattern on Polar

10. Results :
Further Developments
• For enhancing the performance
of satellite on the move DBS
receiver antenna, we have
developed our 4 array of RLSA.
The RLSA array stucture is
composed of 2 x 2 planar RLSA to
get 6 dB gain better, so the overal
antenna gain will 19 dB.
• This further development needs a
power combiner which has
implemented using low cost PCB
FR-4 material. This 2x2 RLSA array
will give better signal reception
for Ku-band transponders of
Indonesian Satellites such as
Palapa-D and the new Telkom-3.

11. Conclusions
• A SOTM (satellite on the move) DBS receiver has been designed and
implemented successfully based on Radial Line Slot Array (RLSA) antenna which
operates at Ku band.
• This RLSA antenna has eight concentric array slot pairs to achieve conical beam,
better gain and wider frequency bandwith compared to Makoto Ando model.
• This prototype antenna has conical beam and elliptical polarization, with 14.22
dBi at 12.0 GHz, operational frequency bandwidth about 1.7 GHz and axial ratio
about 3.79 dB.
• Therefore our prototype has passed the technical specifications and appropriate
for satellite on the move DBS receiver.
• For enhancing the RLSA prototype, we also have developed the 2 x 2 planar RLSA
antena which has about 6 dB additional gain.
• Moreover, this low cost implementation of RLSA antenna will decrese the CAPEX
of DBS deployment at public trains, ships and buses in Indonesia.