Blar i forfatter "Jacobsen, Svein Ketil"

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    • Drone-Mounted Ultrawideband Radar for Retrieval of Snowpack Properties 

      Jenssen, Rolf-Ole Rydeng; Jacobsen, Svein Ketil; Eckerstorfer, Markus (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-13)
      Extracting snowpack parameters from snow cover on sea ice or land is a time-consuming and potentially high-risk task. Moreover, deriving such parameters by manually digging a snow pit evidently yields low area coverage. We, therefore, propose a practical solution to this problem by mounting an ultrawideband radar system onto an unmanned aerial vehicle (UAV) to obtain information such as snowpack ...

    • Drone-Mounted UWB Snow Radar: Technical Improvements and Field Results 

      Jenssen, Rolf-Ole Rydeng; Jacobsen, Svein Ketil (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-04)
      Drone borne radar systems have seen considerable advances over recent years, and the application of drone-mounted continuous wave (CW) radars for remote sensing of snow properties has great potential. Regardless, major challenges remain in antenna design for which both low weight and small size combined with high gain and bandwidth are important design parameters. Additional limiting factors for CW ...

    • High frequency copolymer ultrasonic transducer array of size-effective elements 

      Decharat, Adit; Wagle, Sanat; Habib, Anowarul; Jacobsen, Svein Ketil; Melandsø, Frank (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-05)
      A layer-by-layer deposition method for producing dual-layer ultrasonic transducers from piezoelectric copolymers has been developed. The method uses a combination of customized and standard processing to obtain 2D array transducers with electrical connection of the individual elements routed directly to the rear of the substrate. A numerical model was implemented to study basic parameters effecting ...

    • Measurement of snow water equivalent using drone-mounted ultra-wide-band radar 

      Jenssen, Rolf Ole R.; Jacobsen, Svein Ketil (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-02)
      The use of unmanned aerial vehicle (UAV)-mounted radar for obtaining snowpack parameters has seen considerable advances over recent years. However, a robust method of snow density estimation still needs further development. The objective of this work is to develop a method to reliably and remotely estimate snow water equivalent (SWE) using UAV-mounted radar and to perform initial field experiments. ...

    • Performance of an Ultrasonic Imaging System Based on a 45-MHz Linear PVDF Transducer Array: A Numerical Study 

      Brodal, Eivind; Melandsø, Frank; Jacobsen, Svein Ketil (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      New designs of high-resolution ultrasonic imaging systems that operate in the 30–100MHz region, for example, those based on linear transducer systems, are currently being investigated for medical purposes. Acoustic waves with frequencies in this range can detect microscopic structures in human tissue but will typically only penetrate a few mm because of large attenuation. However, this is sufficient ...

    • Radiometric temperature reading of a hot ellipsoidal object inside the oral cavity by a shielded microwave antenna put flush to the cheek 

      Klemetsen, Øystein; Jacobsen, Svein Ketil; Birkelund, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      A new scheme for detection of vesicoureteral reflux (VUR) in children has recently been proposed in the literature. The idea is to warm bladder urine via microwave exposure to at least fever temperatures and observe potential urine reflux from the bladder back to the kidney(s) by medical radiometry. As a preliminary step toward realization of this detection device, we present non-invasive temperature ...

    • UAV-BORNE UWB RADAR FOR SNOWPACK SURVEYS 

      Eckerstorfer, Markus; Jenssen, Rolf Ole Rydeng; Kjellstrup, Andre; Storvold, Rune; Malnes, Eirik; Jacobsen, Svein Ketil (Research report; Forskningsrapport, 2018)
      In this report we summarize the capabilities and technical characteristics of our UAV-borne UWB radar system, designed for conducting snow surveys. We developed an ultrawideband snow sounder that is capable of imaging snow stratigraphy with a 5 cm range resolution. The radar can be carried by an octocopter UAV in order to carry out airborne snowpack surveys. During a demonstration on Andøya, we ...

    • Using Silver Nano-Particle Ink in Electrode Fabrication of High Frequency Copolymer Ultrasonic Transducers: Modeling and Experimental Investigation 

      Decharat, Adit; Wagle, Sanat; Jacobsen, Svein Ketil; Melandsø, Frank (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-04-20)
      High frequency polymer-based ultrasonic transducers are produced with electrodes thicknesses typical for printed electrodes obtained from silver (Ag) nano-particle inks. An analytical three-port network is used to study the acoustic effects imposed by a thick electrode in a typical layered transducer configuration. Results from the network model are compared to experimental findings for the implemented ...