One of the most important systems in our CanSat is perhaps the communications system, in particular the ground antenna. But how exactly does this work? In this post we will provide a brief overview of the type of antenna we are designing.
The Athena team had decided to use a pair of antennas-the one on our CanSat would be an extremely compact spring antenna, and the one on the ground would be a custom-made antenna. We had two main options for a custom-made antenna: a monopole quarter-wave antenna(quarter-wave means the antenna length is a quarter of wavelength), and the slightly more common and well-known Yagi-Uda antenna. Of course, you would probably disagree when I say “well-known”, but in reality, they are everywhere-usually on household rooftops, as they are antennas used for TV signals, among many other purposes. If you really haven’t seen one, next time you take a stroll, look up to the roofs of your neighbours, or even your own! See some sort of(probably metallic) structure(s) with a main branch and a lot of short structures perpendicular to it? That’s a Yagi-Uda antenna.
The Yagi-Uda antenna was invented by Japanese university student Shintaro Uda in 1926, and commercialised by his teacher Hidetsugu Yagi. During WWII, it was widely used by Japan, Germany, the UK and the US in radar systems, and afterwards were developed and rolled out as household television antennas, much like the ones we see today.
The design of the Yagi-Uda antenna is relatively straightforward. On one side there is a reflector, which helps prevent signals from reflecting backwards in the wrong direction. Around a quarter of a wavelength away is the driven element/dipole(this type of antenna having its length as half of the wavelength), which carries the signal and current, and transmits the signal. Next to the dipole are directors, ranging from 1 to more than 10, that help the antenna transmit a very focused signal. Because of this, Yagi-Udas are often called “ultra-focused antennas”. Supporting the entire antenna(the “main branch”) is the boom. It is the only possibly non-conductive component in the antenna. Our Yagi-Uda antenna will be made of aluminium, and our boom will be made of plastic. Measuring at over a meter, the antenna will have six directors and will transmit signals to and from the CanSat every second.
All in all, the Yagi-Uda antenna is one of the most well-known and widely used antennas in the world, and we believe that it will work extremely well with our CanSat. Thanks for reading this blog post!
As the antenna is still in production stages, we cannot reveal many aspects of the design, but follow our social media channels for updates!
Leave a Reply