IEEE Aerospace and Electronic Systems Magazine - July 2020 - 19

Davarian et al.

Figure 6.
ISARA Ka-band deployable reflect array antenna with 33.5 dBi gain at Ka-band.

the amplifier). In [27], few examples of commercially
available solar panels for CubeSats are shown.

ANTENNAS FOR SMALLSATS
The performance of a satellite communications link is proportional to the gain of the onboard antenna. The larger the
collection area of an antenna, the higher the gain. Since the
dimensions of an antenna mounted on the side of the spacecraft are constrained by the available area on the spacecraft,
SmallSat antennas tend to be of small size with low to moderate gain (<20 dB). To remedy this situation, in recent years
much effort has been given to the design of deployable antennas for SmallSats [28]. The objective is to equip SmallSats
with relatively large size antennas that can stow in a small
space during launch. Moreover, the interest in Ka-band for
SmallSats is also increasing because, for the same size, an
antenna can produce approximately 12 dB gain improvement
over what is achievable at X-band. The following subsections
discuss the current state-of-the-art and provide recommendations for future work.

CUBESAT ANTENNAS
CubeSats present a tremendous challenge for high gain
antenna (HGA) designers due to the limited available
stowage volume and the strict rectangular packaging constraints imposed by the CubeSat P-POD7 launch canister
7

Poly Picosatellite Orbital Deployer (P-POD) is a CubeSat dispenser
standard.

JULY 2020

standard [29]. The ISARA (Integrated Solar Array and
Reflectarray Antenna) Earth-orbiting mission provided the
first on-orbit demonstration of a compact stowage CubeSat high gain antenna. The goal of ISARA was to increase
the amount of data that a tiny satellite can transmit by
adapting its solar array to also function as a communications antenna [30]. To accomplish this, the antenna and
solar array are designed as an integrated unit, with solar
cells on one side of the panel and the antenna on the opposite side. This is made possible by a relatively new type of
antenna known as a reflectarray (see Figure 6), which
uses a printed circuit board that is patterned to mimic the
behavior of a parabolic dish, thereby focusing signals
toward Earth. The ISARA Ka-band reflectarray is comprised of three panels which form a 33.4 Â 26.8 cm2 aperture [31]. It uses spring-loaded hinges to fold the panels,
permitting it to stow in the "dead space" between the outside of the 3U (10 x 10 x 33.5 cm2) CubeSat bus and
inside the P-POD launch canister. Consequently, this configuration consumes essentially zero payload volume. The
ISARA reflectarray successfully deployed on orbit in
December 2017. Flight testing confirmed the unit provides
33.5 dBi gain and $24 W spacecraft power [30]. The
mass is 0.5 kg (including the solar array and feed). It is
notable that the ISARA antenna is the first reflectarray
ever flown in space.
As discussed earlier, the MarCO mission used two
interplanetary CubeSats to provide a data relay for the
InSight spacecraft during its Entry, Descent, and Landing (EDL) phase. These are the first deep space CubeSats to operate from a Mars distance of 160 million

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IEEE Aerospace and Electronic Systems Magazine - July 2020

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