TRW has produced a highly miniaturized radio component that
improves the messaging capability of TRW communications satellite
payloads, while dramatically decreasing size and weight.
Its first use will be in the payloads that TRW is building for the
Astrolink global broadband telecommunications system, slated to begin
service in 2003.
The TRW low-noise amplifier (LNA) downconverter detects and
converts signals received by the satellite’s antennas at frequencies
of 30 billion cycles per second (30 GHz) to much lower frequencies
that are easier to process electronically. Astrolink’s satellites
receive signals from earth at 30 GHz and transmit to earth at 20 GHz,
in a frequency range known as the Ka band.
“Our miniature package shows the advantages of TRW’s advanced
microelectronics for spacecraft use, where weight and size are always
at a premium,” said Paul Borzcik, vice president and program manager
of the TRW Astrolink program.
“Our unit is about the size of a matchbook and weighs little more
than an ounce, yet it contains extensive built-in redundancy for high
reliability. Only five years ago, electronics to perform the same
functions would have required a box weighing several pounds.”
The LNA downconverter is packaged as an integrated microwave
assembly, housing a number of TRW gallium arsenide integrated circuits
designed for Ka band operation. Devices contained in the unit include
low-noise amplifiers, filters, voltage regulators, frequency
converters, low loss redundancy switches and frequency multipliers.
Borzcik said that TRW is now completing the first pre-production
lots of LNA downconverters. Production takes place on an automated
assembly line that greatly reduces manual labor and shortens
manufacturing times.
The pre-production lots are identical to the flight lots and are
being used to verify the mechanical and electrical design of the LNA
downconverters and to validate the automated production processes.
Production of the Astrolink flight units is set to begin in summer of
2000.
The boost to satellite performance results from the LNA
downconverter’s small size, which permits multiple LNA downconverter
units to be mounted directly in the feed assembly of a densely packed
multi-beam antenna. This direct feed mounting, rather than in a box
remote from the feed, reduces signal loss between the antenna and
low-noise amplifier.
In addition, the front-end conversion of the Ka-band receive
signal to a lower intermediate frequency allows the use of coaxial
cables to route the signal from the antenna for further signal
processing. Coaxial cable avoids the weight, expense, and engineering
associated with custom waveguide that would otherwise have to be
employed.
Other key technical features of the LNA downconverter include the
built-in voltage regulators, which result in higher spectral purity of
the signals, and the need for only a single DC power supply, which
simplifies payload integration.
TRW Space & Electronics Group, which is building the Astrolink
digital-switching payloads, is a world leader in satellite
communications and microelectronics. TRW Inc. provides advanced
technology products and services for the global automotive, aerospace
and information systems markets.
