IEEE Aerospace and Electronic Systems Magazine - July 2020 - 54

Space Phased Array Antenna Developments: A Perspective on Structural Design

Figure 11.
Basic schematic of thermal deformation on the subarray surface.

1) About the prototype test of space active phased
array antenna, Nanjing Research Institute of Electronics Technology had developed a principle
prototype of an S-band planar inflatable phased
array antenna with an aperture of 3 m Â 3 m [70].
Shanghai Micro Satellite Engineering Center
designed a planar multibeam transmitting antenna
array with "isoflux" coverage on the basis of the
prototype test for the 16-beam active phased array
antenna. This verified the feasibility of spaceborne
DBF multibeam active phased array antenna system
design [71].
2) As for the surface deformation of spaceborne active
phased array antenna, Liu et al. [72], working at the
National Space Science Center of the Chinese
Academy of Sciences, presented a new method
applied to spaceborne Ku-band waveguide slotted
antennas to analyze the influence of the structural
thermal deformation on antenna electrical performance, and deduced the corresponding mathematical formula. Wei et al. [73], at Zhejiang University,
established the equations of bending-stretching coupling effects for the honeycomb sandwich structure
and analyzed the thermal deformation of space
microstrip antennas. Chen et al. [74], at Beijing
University of Aeronautics and Astronautics, proposed the mathematical model of thermal deformation error on the basis of active phased array
antenna structural characteristics, and deduced the
formula of the antenna pattern when thermal deformation appeared on the antenna array surface.
Meanwhile, they pointed out that there are mainly
two types of thermal deformation on antenna array
surfaces: bending and twisting (see Figure 11). Zeng
et al. [75], at Air Force Engineering University,
determined the influence of the spaceborne SAR
array surface deformation on the antenna beam by
making the position error of the array antenna
equivalent to the phase error and then compensating
for the excitation phase.
3) With respect to the research on the structural-electromagnetic coupling of spaceborne antenna, the
electromechanical coupling research team of
Xidian University have conducted productive
54

long-term research on the related theory of spaceborne antenna and made some fruitful achievements. Wang et al. found the three-field coupling
relationship among the structural displacement
field, electromagnetic field, and temperature field
of active phased array antennas. In turn, they proposed the three-field coupling model of antennas.
Analyses of numerical simulations and experimental verification have also been performed [76]-
[82]. According to the noncoupling dynamic theory and finite element method, Liu et al. simulated
thermal power load by temperature shocks in the
form of half-sine waves, analyzed the thermal
vibration of spaceborne deployable antenna, and at
last came to a conclusion that the response of thermal vibration was significantly greater than that of
statics. In addition, they improved the stability of
antenna structure by adding various heat control
coatings, including the aluminum honeycomb
material, for example in [83].

DESIGN TECHNOLOGY OF ESSENTIAL COMPONENTS
The space active phased array antenna needs to withstand
as long and as arduous the effects of infrared radiation
from the sun and planets and low-temperature heat sinks.
Therefore, it mainly involves the breakthrough of seven
key subsystems. On the one hand, space deployable
phased array antenna has tight requirements on radiation
performance. On the other hand, it is necessary to adopt
the light sheet material to ensure that the antenna possesses the features of large aperture, extensibility, and low
weight. The following gives brief explanations for
research methods of the seven key components and structural technologies in space deployable active phased array
antenna.

T/R MODULE
The spaceborne deployable active phased array antenna is
composed of a large number of T/R modules whose performance directly affects the whole performance of the
antenna. On account of the limitation of transmitting platform, the energy supply under working conditions, fault
diagnosis, and maintenance ability, the main requirements
of the space antenna system for T/R modules are that they
must be lightweight, able to be miniaturized, and have
high efficiency, large bandwidth, and low noise. The
parameters of T/R modules in the two satellite antennas
including ALOS and ALOS-2 are significantly improved:
the power is increased from 25 to 34 W, operation bandwidth is broadened from 28 to 85 MHz, efficiency is
enhanced from 25% to 35%, and mass is reduced from
675 to 400 g. This demonstrates that satellites put high

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JULY 2020

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