The Antenna Project

Goals

The eventual goal of this project is to design and develop 2 phased array antennas. The first is aimed at a small form factor, light weight antenna that is specificaly designed to be used on a drone. The functions of the antenna I want to explore are:

• AESA Radar
• Communications (done to drone, drone to ground, comm relay from ground to drone to destination), High Bandwidth Data Transmission
• SIGINT, Passive Listening
• Electronic Warfare Capabilities

The second will be designed for ground station use, the applications to address will be:

• Communications (ground to drone)
• Counter UAS applications
  • Radar Detection / Targetting Radar focussed on UAS detection and targetting
  • Electronic Warfare

As of the end of 2024, I have spent at least a year researching phased array antenna theory and techniques. At this point however, there is still a long way to go before I have the capability to attempt the goals of this project. The idea fo this project is to start building antennas with increasing complexity of various designs in order to learn some of the fundamentals needed for desigining and building a phased array antenna.

Current Project

The initial iteration is a basic proof of concept antenna build with a motorized base mount. The antenna is designed for L-Band frequencies (1.5 GHz), which are commonly used be satelites. The base will be programmed to track satelites as they transit accross the sky.

Antenna

Design credit: thebaldgeek

As this is my first antenna build, I found someone elses design and followed their steps to build it. This took allot of guesswork out of it on my part and allowed me to get me feet wet.

Gimbal

Design credit: fhuable

Because this particular antenna is designed for L-Band use for satelite signals, it would be very useful to have a satelite tracking mount for the antenna. The ability to control motors for tracking using a high level program interface is something that will be useful in other projects, as well as this one- so even though it is not necesarry for this application at the moment it is still on the table for development. The gimbal is currently considered a sub-project of this project, so I have given it its own page with more detailed information: Satelite Tracking

For the initial version, I thought it would be prudent to explore and build some designs other people have made instead of trying to design one from the ground up with no experience. I ended up finding a design for a camera gimbal and a nice video on assembly (Video).There was no software / control interface designs that were made public with this design, but thats fine because I was planning on building that from scratch anyway. The only physical piece I had to design was a mount so that I could attach the camera to the gimbal.

Roadmap

HAM Radio License

Now that this project is in full swing, I have decided to get my radio license. The purpose of getting the licence is to:

• Get a solid understanding of the laws / rules / regulation around the radio spectrum
• Discover ‘unknown uknowns’ (i.e. radio / antenna theory topics I was no aware of but should learn)
• Learn some foundational radio / antenna theory
• Get my foot in the door of a community of people who might be able to help answer some questions I will innevitably have down the road of this journey

Currently, the plan is to take the exam for the technician license on January 11th 2025. I will likely go for the general and extra in early spring.

Magnetotellurics

This is a topic I have thought about for about 5 years at time of writing, but I am still a distance away from trying to tackle this one- so my description will be brief. There are plenty of resources online to learn about the theory of magnetotellurics if you want to learn more.

Essentially, magnetotellurics is a method typically used in resources exploration that allows you to map the conductivity of the earth in a given area up to several kilometers deep. Basically the mechanism that allows you to do this are very low frequency waves that propogate through the Earth. The traditional way to do this is essentially by drilling a bunch of holes a few feet deep in a grid over the area you want to map, put antenna in each hole, and collect that data, stitch it together, and then interpret it. This is obviously expensive (requires allot of equipment, manpower, and time to set up), as well as restrictive (you are limited to the area you place the grid, if you want to look at the field next to it you have to redo everything).

There is a single company in the world (that I am aware of) that is trying to improve upon this technique to bring down cost and expand capabilities. The company is called Expert Geophysics, and they have developed a tool they call Mobile MT (MT = magnetotellurics). Basically they hang an antenna underneath a helicopter, and are (apparently) able to gather the same data, but now you are not limited in the search area.

My contention is that this idea of mobile magnetotellurics can be improved further by using a drone swarm with smaller antennas undereath each, arranged in a grid formation, and more or less automated to do the same thing at a significantly lower cost. Helicopters are very expensive to operate and maintain. The main reason they use a helicopter is because the antenna they use is very large and heavy. The idea of using multiple smaller antennas (an antenna array) is based off of the traditional method, as well as some radio telescope techniques used to increase the effective size of an antenna using several small antennas. I really think this is feasible in theory, but I currently do not have enought experience in antenna theory, signals processing, geology, drone swarms, etc to attempt this right now. This is a major goal of mine, however- and you will notice that many of my projects will develop the skills needed to do this eventually.

If you think this sounds cool and want to work on this with me / bring some skills to the table that will be necesarry to achieve this, please contact me!

Radar

I have gone through an MIT OCW course on radar theory, and want to explore it a bit more. Ultimately, I want to work on several components for a ground based counter-UAS system. This would most likely include a radar detection, tracking, and targetting component. Inspired by Jon Kraft

Phased Array Antenna

The concept of phased array antenna has fascinated me for years, and the more I look into the uses and theory behind it- the more I want to build one and put it to use. Currently, I have read 2 books on the subject Ultrawideband Phased Array Antenna Technology for Sensing and Communications Systems (MIT Lincoln Laboratory Series) MIT Lincoln Laboratory Series and Active Electronically Scanned Arrays: Fundamentals and Applications as well as a few academic papers and a number of youtube videos. At this point however, I am still lacking enough knowledge on the topic to be able to intuitively design one from scratch even though I know the applications I want to optimize for. This is why I have made a blanket “Antenna” project to start with simple antenna designes and applications and build the knowledge base to tackle phased array later on.

Communications

This is a bit high level, as im not sure exactly what I want to explore here. Current 5G towers use phased array antennas for communication networking, and there are many other communication methods. I’m not exactly sure what I want to do in this space, but I do know I want to build an ad-hoc networking protocol for a sort of air traffic control for drones- a “Drone Area Network” if you will. More to come on this later.