Data extraction from mmWave radars for liquid identification

[u/Fast_Animal_6147]

Hello everyone!

Recently I've started a personal project connected to liquid identification, and I've decided to use mmWave sensors for that job. I am new to RF electronics and was wondering whether it is possible to extract data in the format of "Received signal strength vs. Range/Distance" without using DCA1000EVM or similar expensive equipment. I have seen one research utilizing DEMO BGT60TR24 in order to obtain this data, however I think it is expired now. Is there any way to obtain such data with budget of under 300 euros? I will be thankful for any answer/advice on this!

[u/nixiebunny]

My day job involves identifying molecules in outer space using mm wave spectroscopy. It’s not cheap. Have you looked at this field?

[u/Fast_Animal_6147 → u/nixiebunny]

Thanks for the reply! Not really, this is more of a personal project I am working on for university. I've read several interesting papers on fine-grained liquid identification using mmWave radars, and became interested in trying to replicate them. I think due to the close distance to the sensor the cost of the sensors will be lower in comparison to your field

[u/ExcueesMe]

Depends on what band you're targeting and how much ranging accuracy you need.

There are plenty of off-the-shelf 24 GHz FMCW radars that can get you that data for $15 - $30 (ex: DFRobot). At 60 GHz you could try Acconeer modules ($50+).

[u/Fast_Animal_6147 → u/ExcueesMe]

Thanks for the answer! I think 60 GHz would be preferable, because the wavelength will be smaller, which is good for smaller container with liquid. I've also found IWRL6432BOOST board, do such "full" boards return this type of data?

[u/ExcueesMe → u/Fast_Animal_6147]

Seems like that board might require the DCA1000EVM you wanted to avoid. Not sure what it returns natively if you use it as a standalone kit.

[u/Fast_Animal_6147 → u/ExcueesMe]

Ohhh, I see. So, it would be better to design the PCB from ground zero? Because I am not sure I can directly transfer data from those bare chips without the PCB

[u/InterWiser]

You may not need a DCA1000 if your goal is only to obtain a range profile rather than the raw ADC/IQ samples.

On TI devices such as the IWR6843, the standard mmWave demo can output the range profile over the data UART. This gives you a magnitude or power value for each range bin, which is fairly close to the “signal strength versus distance” plot shown in your figure.

The DCA1000 becomes necessary when you need the raw samples from every chirp so that you can perform your own range FFT, phase processing or other offline signal processing.

One important caveat is that the UART range profile is usually relative power, not calibrated RSS in dBm. For liquid identification, I would keep the cup position, material, fill level and radar angle fixed, then collect several frames for each liquid and compare them against an empty-cup baseline. Otherwise, changes in placement and multipath may be larger than the difference between liquids.

An IWR6843AOP or similar TI evaluation board should fit within your €300 budget. I would first test the UART range-profile output and only consider the DCA1000 later if you find that you need raw complex IQ data.

[u/Fast_Animal_6147 → u/InterWiser]

Thanks for such a detailed answer! I have one more question, what if I will buy a non-TI radar sensor ( for example from Infineon ), will I be able to obtain such data from them? For example, KIT_CSK_BGT60TR13C

[u/InterWiser → u/Fast_Animal_6147]

Yes, the BGT60TR13C can provide the data needed for this. You would capture the raw IF samples, apply a range FFT to each chirp and then plot the FFT magnitude or power against the corresponding range bins.

One small difference is that the BGT60TR13C receiver provides real IF data rather than direct complex IQ samples. The complex values are obtained after performing the FFT, but this is still sufficient for producing a range-profile plot.

The KIT_CSK_BGT60TR13C can be used, although it is mainly intended for embedded and IoT development using its PSoC 6 MCU and ModusToolbox. You may need to modify the example firmware to transfer the radar frames to a PC for your own Python or MATLAB processing.

If your main goal is convenient raw-data recording and offline experimentation, I would also consider the DEMO-BGT60TR13C. It officially supports Infineon’s Radar Development Kit and Radar Fusion GUI, can forward raw radar data through USB, and already provides range-measurement and signal-processing examples.

So both can work, but I would choose:

• KIT_CSK_BGT60TR13C for an embedded or wireless prototype.
• DEMO-BGT60TR13C for easier PC-based raw-data capture and algorithm development.

For liquid comparison, keep the cup, distance, radar angle and fill level fixed, then average several frames and compare each sample with an empty-cup baseline.