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Passive Microwave Polarimeters

Highly Advanced Soil Moisture Sensors for Research, Academia, and Progressive Farms.

No annual subscription, free online data processing (optional), documentation available, tailored to support research.

Passive microwave sensing offers a unique technique to measure soil moisture levels from a distance. This method relies on the natural emissions of microwaves by the soil. Wet soil emits less microwave radiation than dry soil, mainly due to the dielectric properties of water. By detecting and analyzing the intensity of these emissions using airborne or ground-based sensors, it is possible to deduce the amount of moisture present in the soil.

P-Band (400 MHz), L-Band (1.4 GHz), S-Band (2.2 GHz)

Digital auto- and cross-correlation polarimetry

Land-Surface Model to support data interpretation

Automatic Cloud Processing & Calibration (optional)

What We Offer

The ability to map root zone and surface soil moisture using dual-polarization microwave radiometers.

Our Microwave sensors have been flown by UAVs, driven by tractors, sprayers, ATVs and mapping trucks, and mounted to irrigation centre-pivots on dryland and irrigated fields worldwide.


Why Choose Skaha Labs

Lightweight, Compact, Versatile

The entire UAV sensor weighs just over 1000 grams. The antennas of the pivot and vehicle-mounted sensors weigh only 2.5 kg. 

The digital processor is built into the L-Band (UAV) sensor. In the P and S-Band sensors, the processing unit is separated from the antenna.

Exceptional Sensitivity

Utilizing high-quality RF components, our uncooled polarimeters achieve a notably low receiver noise temperature of just 150 Kelvin. Thanks to internal calibration against a temperature-monitored fixed load, these Dicke-type polarimeters ensure exceptional stability and minimal system noise.

Cross-Correlation Polarimeter

At the heart of our sensors are a wide-band Analog-Digital Converter (ADC) and a Field Programmable Gate Array (FPGA), which perform real-time correlation and Fast Fourier Transform (FFT) of horizontal and vertical polarization.

This is not only a radiometer; it's a digital polarimeter!

Support by Experienced Scientist

As the founder of Skaha Labs, Maik has personally designed, constructed, field-tested, and fine-tuned every iteration of his sensors. With a background in physics and skills as a self-taught engineer, Maik's vision is to witness his technology making contributions in both research and agriculture. He is deeply committed to supporting Skaha's customers.

German Engineering, Made in Canada

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The Mueller Irrigation Research Group works with Skaha Labs to rigorously test their microwave radiometers under varying field conditions. In our collaboration, Skaha Labs has demonstrated to be committed to developing a product that has great value for water management decision making by irrigation farmers.

Dr Willemijn Appels

Mueller Applied Research Chair in Irrigation Science, Lethbridge College, Lethbridge, Alberta, Canada

We have been working with Skaha Labs on the development of a closed-loop irrigation solution for farmers since 2019. Thanks to Skaha's microwave sensors which make the creation of high resolution soil moisture maps of agricultural fields much easier and more affordable, we have made significant progress towards our goal.

Prof Dr Jinfeng Liu

Donadeo Innovation Centre For Engineering, University of Alberta

We purchased a Skaha Labs drone sensor two years ago and are getting some really exciting results from this instrument. Working with Maik Wolleben is great, as he offers excellent support.

Prof. Aaron Berg

University of Guelph

Canada Research Chair in Hydrology and Remote Sensing

Guelph, Ontario, Canada


Radio Interference

Skaha's sensors utilize state-of-the-art passive microwave radiometry to detect and measure the subtle radio emissions emitted naturally by soil. While we've incorporated robust interference mitigation strategies to ensure accuracy, there are instances where external, human-made radio interference can overpower our instrument.

Potential users should be aware of conditions that may disrupt the sensor's performance:

  • The presence of electronic devices near the sensor.

  • LCD screens situated within approximately 10 meters of the sensors.

  • Proximity to communications infrastructure such as cell towers or broad-band communication antennas.


It's also worth noting that taking measurements inside university premises or industrial buildings is often not feasible due to the prevalent radio interference in such environments.



  • What is a microwave radiometer, and how does it work?
    A microwave radiometer is a device used to measure soil moisture by detecting microwave emissions from the ground. It operates based on the principles of radiometry and measures the naturally occurring microwave radiation emitted by the soil.
  • What is the difference between a digital polarimeter and a radiometer?
    A digital microwave polarimeter analyzes the polarization state of microwave signals. In contrast, a microwave radiometer can only measure the intensity of microwave radiation. Our polarimeters are equipped with an FPGA chip that employs Fast Fourier Transform (FFT), captures and rapidly processes microwave signals to analyze their polarization states.
  • Is this a passive or active (radar) sensor?
    Our sensors do not emit microwave radiation; they are purely passive sensors.
  • What is the difference between the P-Band sensor for irrigation and vehicles?
    Aside from the mounting frame, the largest difference is in the firmware. Irrigation systems move slowly and we can afford longer sampling times to keep data rates low. The sensor for irrigation is also equipped with a cellular modem as well as battery charging circuitry for solar powering the sensor. The vehicle sensor has higher sampling rate, a user dashboard, and an option to connect the sensor to Ethernet.
  • Can the Antenna HPBW be improved to 10 degree?
    Technically it is possible but it is not something we could do easily and quickly.
  • Is this Polarimeter a full-polarization radiometer? Can it provide the brightness temperature of H- and V-pol?
    Yes, it can provide polarization in H and V and can distinguish between polarized and unpolarized components. This means, it tells you how much of the incoming radiation is polarized and what the polarization vector is of that component.
  • Must the measured data be uploaded to the server for processing and calibration? Can the data be processed locally by software?
    Either way. Uploading to our server is optional. However, We do not provide processing software. All processing is doen by uploading to our server, so this is the easiest way to get started. You can download raw data from the sensor, which is in hdf5 format, so it should be relatively easy to use.
  • Can the radiometer be used for research applications?
    Yes, our radiometer is suitable for research and can be employed in various scientific studies related to soil moisture and agriculture.
  • Do you offer drones for data collection?
    We have partnered with Drone Geoscience ( and can source and assemble a drone and microwave sensor combo for you.
  • Do you offer support for installation and setup?
    Yes, we provide guidance for sensor setup and offer recommendations for suitable UAVs (Unmanned Aerial Vehicles) for data collection. Feel free to contact us for assistance.
  • Can the microwave radiometer be used in agriculture other than turf grass and golf courses?
    Yes, it can be used in a variety of agricultural applications, including monitoring soil moisture in crop fields, orchards, and vineyards. Please contact us for specific recommendations.
  • The calibration process is unclear to me, it seems different with other radiometers which use cold and hot loads for calibration. Could you explain the calibration process?
    Cloud processing includes an absolute calibration based on a land surface model. The model calculates the average soil moisture for the field you are mapping and calibrates to radiometer data accordingly. However, a hot/cold calibration is always possible - it just isn't used in the online processing. It is something you would have to apply on your own.
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