Upload
others
View
12
Download
0
Embed Size (px)
Citation preview
20 mm
0.85λλλλo
Parallel-plate
structure
2λλλλp
0 100 200 300 400 500 600-180
-150
-120
-90
-60
-30
0
30
Ez
ph
ase [
deg]
Initial 1st iteration
Position of Feeder in direction [mm]
Coupling Slot
y
0 100 200 300 400 500 600 700-120
-90
-60
-30
0
30
60
90
120
Ex,E
y P
has
e [
deg
]
Position of Raditing Panel in direction [mm]
Ex phase (1st iteration)
Ex phase (Initial)
Ey phase (Initial)
Ey phase (1st iteration)
Radiating Slot
x
Short
��
� Hardwall
hw
Wp
Lp
Hardwall
zx
y
Lf
Antenna input
Parallel plate
Feeder
RHCP port
Satellite
Body
One Antenna Panel
(current design is RHCP)
Rectangular waveguide
feeder to each panel
[top view]
[bottom view]
Choke Flange
x
z
y
70 cm70 cm
LHCP port
xz
y
Parallel-Plate Slot Array Antenna for MicroXSAR Mission
† Institute of Space and Astronautical Science - Japan Aerospace Exploration Agency (ISAS - JAXA)‡ Tokyo Institute of Technology
AbstractRectangular parallel-plate slot array antenna fed by
rectangular waveguide at its bottom sides has been proposed.
This antenna will be implemented for dual polarized deployable
Synthetic Aperture Radar (SAR) antenna onboard 100 kg small
satellite. As to verify the possibility of the implementation of
this antenna, experiment on one antenna panel (about 700 mm x
700 mm) with right handed circularly polarized radiation has
been conducted. This paper describes the design of this one
antenna panel using simplified model in HFSS. Moreover, the
measurement results of the fabricated antenna will be
discussed. It is shown that 80 % aperture efficiency with the
directivity of 36.5 dBic and 55% antenna efficiency with the
gain of 34.9 dBic are achieved at 9.65 GHz as the targeted
center frequency.
Keywords : small SAR sensor, rectangular slot array antenna, X-
band antenna
Prilando Rizki Akbar††††,,,,Hirobumi Saito††††,,,, Miao Zhang ‡, Jiro Hirokawa ‡ and Makoto Ando ‡
References
1. M.iao Zhang, Jiro Hirokawa and Makoto Ando,
“Design of a partially-corporate feed double-layer
slotted waveguide array antenna in 39 GHz band and
fabrication by diffusion bonding of laminated thin
metal plates,” IEICE Trans. Commun., vol. E93-B,no.10, pp.2538-2544, Oct. 2010.
2. Tung Nguyen, Rushanthi J., K. Sakurai, J. Hirokawa,
M. Ando, M. S. Castaner, O. Amano, S. Koreeda, T.
Matsuzaki and Y. Kamata, “Propagation
characteristics of honeycomb structures used in mm-
wave radial laine slot antennas,” IEICE Trans.Commun, vol.E97-B, no.6, pp.1139-1147, June 2014.
3. Prilando Rizki Akbar, Hirobumi Saito, Miao Zhang,
Jiro Hirokawa and Makoto Ando, “Slot Array Antenna
for X-SAR onboard A Small Satellite,” in Proc. IEICEGeneral Conference, 2013, B-1-100.
P-279
x
z
y
Antenna panel
(parallel-plate slot
array antenna and
its rectangular
waveguide feeder)
Choke Flange
Satellite
body
xy
z
Upper Aluminum plate
Radiating slot
Honeycomb core
Adhesive sheet
Adhesive sheetLower Aluminum plate
ts
tg
tc
[Parallel Plate Structure]
60 80 100 120 140 160 180-2200
-2000
-1800
-1600
-1400
-1200
-1000
-800
-600P
hase
[d
eg]
Position from center [mm]
β = −11.92
60 80 100 120 140 160 180-2200
-2000
-1800
-1600
-1400
-1200
-1000
-800
-600P
hase
[d
eg]
Position from center [mm]
β = −11.92
W drection
[bird view]
Coupling slot
Inductive
wall
Feeder Parallel-plate
structure
��
�
b
a
[single coupling slot]
z
x
y
[top view]
Feeder
PBC
Input Port
Port 3
Port 2
il
i w
rs ip
γγγγ
sw
��
�PBC
sl
Inductive
wall
2��
z
y
x
z
y
x
Short
Input port
ds(n, n-1)
��
�
Hardwall
Hardwall
Coupling slot
Inductive wall
Impedance
boundary
Parallel-plate
structure
Feeder
n = 1
n = N
��
�
[Coupling slots at feeder of one antenna panel]
Input port
Short
ds
[Fabricated Feeder]
z
y
x
��
�
rl
sw
Rs
dx
dy
rl
135°°°°
45°°°°
Center of radiating
slot pair
[one radiating slot pair ]
xy
z
xy
z
Parallel-plate
structure
��
�
dr (m, m-1)
Radiation
boundary
m = 1
m = M
[1 dimensional array of radiating slot]
zy
x
Parameters Size (mm)
Parallel-plate (Wp x Lp)
Feeder Length (Lf)
Feeder inner size (a x b)
Inductive wall width, iwSlot width, swSlot round edge radius, rsHardwall width, hwThe thickness of
- Aluminum skin sheet, ts- Adhesive sheet, tg- Honeycomb core (SAH-1/4-1.5) , tc- Hardwall
- Feeder broad wall
657.2 x 700
678.4
22.86 x10.18
1
2
1
4.89
0.3
0.13
6
6.26
1
Item Mass (gram)
Upper parallel aluminum plate
Lower parallel aluminum plate
Honeycomb core sheet
Adhesive sheet
Hard Surface wall
Aluminum Frame
Feeder waveguide
Total antenna system
344
358
65
138
57
24
162
1148
-90 -60 -30 0 30 60 90-50
-40
-30
-20
-10
0
YZ Plane
Angle [deg]
No
rmal
ized
Rad
iati
on
Pat
tern
[d
B]
RHCP LHCP 19.01 dB
-90 -60 -30 0 30 60 90-50
-40
-30
-20
-10
0
XZ Plane
Angle [deg]
No
rmal
ized
Rad
iati
on
Pat
tern
[d
B]
RHCP LHCP 19.01 dB
-5 -4 -3 -2 -1 0 1 2 3 4 5-20
-15
-10
-5
0
XZ Plane
Angle [deg]
No
rmal
ized
Rad
iati
on P
atte
rn [
dB
]
9.57 GHz 9.65 GHz 9.73 GHz
-5 -4 -3 -2 -1 0 1 2 3 4 5-20
-15
-10
-5
0
YZ Plane
Angle [deg]
Norm
aliz
ed R
adia
tion P
att
ern [
dB
]
9.57 GHz 9.65 GHz 9.73 GHz
9.6 9.65 9.7-40
-35
-30
-25
-20
-15
-10
-5
0
Frequency (GHz)
S
[d
B]
One dim. radiating slot array (simulation) Feeder of one antenna panel (simulation) Fabricated antenna (measurement)
112
9.6 9.65 9.731
32
33
34
35
36
37
0
1
2
3
Frequency (GHz)
Dir
ect
ivit
y,
Gai
n (
dB
ic)
30%
40%
50%
60%
70%
80%
Directivity without back panel Directivity with back panel Gain (5.82 m) with back panel Gain (16.85 m) with back panel Axial ratio (16.85 m) with back panel
Ax
ial Ratio
(dB
)
1.6 dB0.02 GHz
0 10 20 30 40 50 608
10
12
14
16
-160
-140
-120
-100
-80
-60
-40
-20
0
[mm]
Coupling Factor (%)
Rad
iati
ng s
lot
len
gth
[m
m]
Phase
[deg
]
rl
[deg]
[deg]
S21
S31
Coupling slot Design
Radiating slot Design
Honeycomb core properties
,2
2
rc
=
π
βλε 0
εεεεrc = 1.06
z
y
x
z
y
x
Near Field Measurement
Amplitude
Phase
Aperture Distribution
Antenna Pattern
• The TE10 mode wave propagates in the
feeder to y direction.• Then the wave in the feeder is coupled to
the parallel plate by the coupling slots.
• The coupled wave travels in the parallel
plate to x direction.• Then this wave is coupled to z direction by
the radiating slots and becomes the
radiated wave.
Beam Shift
In the feeder, wave travel only to
positive y direction
Beam Shift
In the parallel-plate, wave travel
only to positive x direction
Input
Results of single coupling slot
simulation are used in the design of
feeder of one antenna panel.
Spacing of coupling slots are adjusted to
obtain optimum in-phase excitation (in
final the average spacing ≈≈≈≈ 1.03 λλλλf ).
Short
Results of one radiating
slot pair simulation are
used in the design of one
dimensional array of
radiating slot.
Spacing of radiating slot pair are
adjusted to obtain optimum in-phase
excitation (in final the average spacing ≈≈≈≈
0.9 λλλλ0 ).
Input Short
The measured antenna directivity, gain and axial
ratio. Here, adjustment factor equals to 1.7 dB and
0.08 dB are added to the antenna gain that
measured in 5.82 m and 16.85 m distance,
respectively.
(5.82 m and 16.85 m)
102 103 104 105
-20
-10
0
Precise Solution Far Field Estimation
E-F
ield
In
ten
sity
[d
B]
Distance [mm]
Adjustment
factor
0 10 20 30 40 500
5
10
15
20
-125
-100
-75
-50
-25
0
25
50
Coupling Factor [%]
[mm
]
[deg
]
γ [deg] [mm]
[mm]
[mm]
Sl
ip
il
[deg]
[deg]
arg.S21
arg.S31
Far Field Measurement
[Inner field measurement]
[Honeycomb inserted
in the WR90]
0 100 200 300 400 500 600-1.4
-1.2
-1
-0.8
-0.6
-0.4
-0.2
0
Travelling Distance (mm)
Loss
(dB
)
α = 0.0023 dB/mm
4.1 mm height of honeycomb 8.2 mm height of honeycomb
9.65 GHz
,4 eqwall εε
λ
−= 0
wh
( )( ).
tt2
tt2
rgcrcg
rgrccg
eqεε
εεε
+
+=
εεεεrg = adhesive permittivity
εεεεrc = honeycomb permittivity
εεεεwall = hardwall permittivity
λλλλ0 = free space wavelength
This document is provided by JAXA.