pace is the new frontier. The current Mars missions, driven by separate teams in several nations, are only a glimpse of how far we have come. Satellite technology has matured into an essential part of Earth’s

infrastructure, providing communications, navigation and observation for decades. As with any vertical sector, the space industry has

evolved with experience. There is no denying that space remains a hostile environment, with extremes in temperature and constant exposure to radiation to contend with. Surviving launch velocity is also a major design consideration, particularly for sensitive electronic devices. In the several decades since the first satellites were put into orbit, the technology used inside them has tracked the progression made on Earth. There are, of course, significant differences between components that are qualified for use in consumer or industrial applications here on Earth, and those that are suitable to operate under the conditions found in space, but in general the companies involved in the space industry are keen to exploit advancements in integration and processing capabilities. The lessons learned over the course of the

industry’s maturity mean those companies are now in a position to better assess what qualification is needed and when. Testament to this is the increasing use of COTS (commercial off-the-shelf) components in space applications. This is in a bid to maximise re-use and minimise cost, as well as accelerate the overall design and qualification processes. But there are some components that remain “mission critical” and must comply with the highest possible qualification. These QPS (qualified parts for space) are only available from suppliers that have been assessed by relevant agencies.

RF COMMUNICATIONS IN SPACE One of the key features that all satellites support is RF communications. It would be unusual for any satellite today to operate entirely autonomously and without any form of RF communications link. For many, providing communications is their primary function. Projects including Starlink from Elon Musk and Kupier from Amazon, along with other commercial enterprises such as OneWeb, are launching satellites to create global space-based infrastructures to bring internet connectivity to every part of the globe. If and when they are all complete, it would increase the number of LEO (low Earth orbit) satellites from under 3,000 to as many as 20,000 in just a few years. While these efforts embody many design

objectives, delivering reliable RF communication systems could be considered the most imperative. Radio frequency communications is complex, even on earth, and it involves multiple functional blocks that must work cohesively. Of all the areas of specialism within electronics, RF is still held up as being particularly challenging. It often relies on the most subtle variances in component value or even placement. The length and shape of a PCB track, for

18 /// Testing & Test Houses /// June 2021

Demand is increasing for qualified RF communication devices for use in space applications, explains Tibor Urbanek, product manager at Bel Fuse

RF devices in tune with space

example, often needs to be carefully characterised if it is to operate as expected at the frequencies needed. It is the nature of RF that each functional block requires the signal to be provided at its input within specific input levels. These input levels may often not be the same as the output levels of the preceding function. For example, in a typical system there will be an antenna with an amplifier and transmitter, but there may also be a combiner and invariably the system will also include up-converters and down- converters.

❱❱ Tibor Urbanek, product manager at Bel Fuse, says the space industry is placing increasingly stringent requirements on RF component suppliers

At each stage, the output needs to match the requirements of the next stage’s input, or at least not exceed them. Managing this is the task of the attenuator. An RF attenuator is essentially a resistive element placed in the signal path that reduces the signal’s magnitude, in terms of dB, without changing any other parameter. The quality of the attenuator is fundamental to the overall system quality, so the

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