Page 62 - SAMENA Trends - August 2020

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Ka-Band Transceiver for Satellite Communications

Scientists at the Tokyo Institute of side, a high-quality-factor transformer and power consumption of the transceiver.
Technology and Socionext have developed is employed to achieve efficient power The scientists have created a prototype
a transceiver for enabling seamless use and high linearity in transmission, chip to test the actual performance of
communication between earth ground which results in lower distortion during their design when using all the modulation
platforms and satellites in the low, middle, transmission. The receiver (RX) side schemes regulated by the SATCOM DVB-
and geostationary earth orbits. According features a dual-channel architecture that S2X standard. This includes high-order
to the scientists involved in the project unlocks several capabilities. By having two modulation techniques like 64 APSK and
this transceiver could help to bring the RX channels it allows for receiving signals 256 APSK, which provide fast data rates.
Internet to people in remote rural areas from two satellites simultaneously. These The performance test results are said to be
and at sea. Despite communications signals are received in parallel using either very promising, especially when compared
technologies having advanced rapidly two independent polarization modes or with other existing SATCOM transceivers.
there are still issues when it comes to two different frequencies. In addition, the Commenting Prof Okada said, “Our paper
bringing connectivity to remote locations, proposed design can perform adjacent- presents the first Ka-band SATCOM
such as rural areas or the open sea. channel interference cancellation; that is, transceiver implemented using standard
Satellite communication (SATCOM) is an the 'contamination' on a signal received CMOS technology and designed for an
attractive option for providing data links to in one channel by another signal on an earth ground platform communication
such places; but for effective SATCOM, the adjacent frequency band is eliminated using with geostationary and low Earth orbit
right equipment must exist both in space information received at the other channel. satellites.” These orbits are at 35,786
and on Earth. At the forefront of research This strategy increases the dynamic range km and 200–2,000 km, respectively.
into SATCOM technologies are scientists of the system, thus allowing it to operate “Satellite communication has become a
from the Prof Kenichi Okada’s lab at Tokyo correctly even in less-than-ideal scenarios key technology for providing interactive TV
Institute of Technology (Tokyo Tech), who with stronger noise and interference. Both and broadband internet services in low-
have developed a transceiver for SATCOM the TX and RX perform direct conversion density rural areas. Implementing Ka-band
using standard CMOS technology. The of a signal; that is, the TX directly converts communications using silicon - CMOS
transceiver, which operates in the 'Ka a baseband signal into a modulated signal technology in particular - is a promising
band', means a 27–31 GHz frequency and the RX performs the inverse process solution owing to the potential for global
range for uplink (ground to satellite) and without additional intermediate frequency coverage at low cost and using the wide
17–21 GHz range for downlink (satellite conversions, unlike the more commonly available bandwidth,” said Prof Okada.
to ground). The design carries a variety used superheterodyne receivers. This
of features. On the transmitter (TX) helps to reduce the overall complexity, size,

SNC Unveils New Satellite Platforms

Sierra Nevada Corporation) Sierra Nevada launched DSX into MEO and it has been higher radiation environment in MEO, and
Corporation (SNC) has added two new operating successfully on-orbit for the large reaction wheels and torque rods
satellite platforms to its spacecraft past year. “We are proud to be able to say for control of the ESPA ring with large
offerings, the SN-200M satellite bus SNC is in a small, select group of satellite payloads attached. DSX includes two
designed for medium-Earth orbit (MEO) suppliers who’ve delivered a proven MEO large deployable booms of 80-meters and
and the SN-1000, offering increased spacecraft,” said SNC CEO Fatih Ozmen, 16-meters. “The SN-200 bus was first
payload capacity for MEO and other orbits. referring to the on-orbit success of DSX. proven as a standalone satellite bus with a
The SN-200M variant specifically adapts “Our unique SN-1000 approach supports standard payload capacity close to 250kg
SNC’s standard SN-200 bus for the MEO increased payload demonstrations or back in 2006 during the TacSat-2 mission,”
radiation environment. The SN-1000 is a operational missions in any orbit.” The SN- said John Roth, vice president of business
demonstration platform based on the SN- 1000 platform can host one large payload development for SNC’s Space Systems.
200M bus flying an Evolved Expendable or multiple payloads at the same time “With the addition of the of the ESPA
Launch Vehicle (EELV) Secondary Payload using a common bus to provide power, Grande ring in the SN-1000 configuration,
Adapter (ESPA). Both satellites build attitude control, communications and each port can hold 700-800kg of payload,
on the flight heritage gained from the other standard functions. Its architecture greatly increasing capacity. The SN-200M
Air Force Demonstration and Science evolved from SNC’s 250kg SN-200M can also be used alone as a standard bus
Experiment (DSX) program. Last June, satellite utilized on DSX that included hosting payloads in MEO.”
the Air Force Research Laboratory (AFRL) additional radiation shielding for the

62 AUGUST 2020