IEEE Aerospace and Electronic Systems Magazine - July 2020 - 55

Wang et al.

Figure 12.
Efficiently integrated components.

For active phased array antennas with a plurality of radiating elements, each unit or sub arrays can realize the
beam scanning using the phase shifter connected with
itself. That is, the phase shifter can feed the phase of
each antenna element, and provide phase distribution of

the antenna aperture, which is used for beam scanning or
beam shape changing. The phase change of the phase
shifter can be done by electronic control. Hence, not
only is the speed of beam scanning very high, but also
the shape, number, and movement mode of the beam is
able to be set in advance or controlled whenever necessary. The electronically-controlled phase shifter is an
essential component of space active phased array antennas, for which the main requirements are high accuracy
in phase shifting, stable phase shifting value that does
not change with temperature or signal level, low insertion loss and VSWR, high power capacity, quick phase
shifting, and low control power. In addition, small volume, a low weight, long life, and low cost are of equal
importance.
In the field of space T/R modules, RF MEMS technology has a good application prospect because it can not
only significantly decrease the size of the phased array
antenna, but also reduce the structural weight. Because of
the outstanding performance of MEMS T/R module in
low power consumption, it can mitigate the cooling problem of phased array antennas and extend their life. Compared to the traditional T/R components, the insertion loss
of MEMS T/R component is much lower. Thus, 25%-
50% of the T/R components are in the general phased
array, which is enough to meet the functional requirements of the antenna system [87]. Due to MEMS devices
with the features of high linearity, wide bandwidth, and
high isolation, the application of MEMS T/R can improve

Figure 13.

Figure 14.

High-power amplifier and T/R components.

T/R module front-end with GaN MMIC chips.

requirements on the integrated performance of T/R
components.
Figure 12 shows a light efficient T/R component with
a size of 63.5 Â 38.1 Â 6.35 mm3 and a weight of 100 g,
developed by NASA [84]. The deployable active phased
array antennas on the Japanese PALSAR satellite, ESA's
ASAR satellite, Canada's RADARSAT-2, Germany's
TERRASAR-X satellite, and the U.S.'s DISCOVER-2 satellite, all adopted a chip-type T/R component (see
Figure 13), which has the features of a small volume, low
weight, high efficiency, and easy integration with radiation elements. The work in [85] provides a successful
implementation of the aerospace T/R module with a peak
power of more than 100 W and a mass of less than 600 g
by using LTCC, microassembly technology, a highly integrated drive module, a high energy capacitor, and a structural optimization design. With the rapid development of
monolithic microwave integrated circuit technology, lightweight and miniaturized T/R modules will be greatly
improved (see Figure 14) [86].

PHASE SHIFTER

JULY 2020

IEEE A&E SYSTEMS MAGAZINE

IEEE Aerospace and Electronic Systems Magazine - July 2020

Table of Contents for the Digital Edition of IEEE Aerospace and Electronic Systems Magazine - July 2020