Kristian Gjertsen Kjelgård

• Rahman, Habibur; Recha, Adrian Miguel Llop; Wisland, Dag Trygve Eckhoff & Kjelgård, Kristian Gjertsen (2025). Dual-Mode Resonant Sensor for Depth Spectroscopy. In Manganaro, Gabriele (Eds.), 2025 IEEE International Symposium on Circuits and Systems (ISCAS). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9798350356830. p. 1–5. doi: 10.1109/iscas56072.2025.11043763. Full text in Research Archive
• Rahman, Habibur; Recha, Adrian Miguel Llop; Wisland, Dag Trygve Eckhoff & Kjelgård, Kristian Gjertsen (2025). Conure: Expanded Surrogate-Based Artwork Generator for RFCMOS Transformers. In EuCAP (Eds.), 2025 19th European Conference on Antennas and Propagation (EuCAP). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9788831299107. p. 1–5. doi: 10.23919/eucap63536.2025.10999249. Full text in Research Archive
• Recha, Adrian Miguel Llop; Wisland, Dag Trygve Eckhoff; Lande, Tor Sverre & Kjelgård, Kristian Gjertsen (2024). Modelling of differential probing analysis for biomedical dielectric spectroscopy. IET Science, Measurement & Technology. ISSN 1751-8822. 19(1), p. 1–12. doi: 10.1049/smt2.12216. Full text in Research Archive Show summary

  Transcutaneous microwave dielectric spectroscopy holds promise as a modality for non-invasive subcutaneous biomarker monitoring, such as blood glucose levels. Experimental studies have demonstrated a strong correlation between blood glucose concentration and blood permittivity using microwave signals. However, the sample volume of interest, blood vessels, is located underneath skin layers where the microwave signal interaction with other surrounding biomaterials is accumulated. Here, a computational study of the proposed method to mitigate the contribution of unwanted tissue and thereby increase the specificity of subcutaneous spectroscopy, using differential probing analysis (DPA), is presented. By exploiting the relationship between the diameter of an open-ended coaxial probe (OCP) and the size of its protruding electric field, two OCPs with different sizes can sense different volumes beneath the skin. The proposed method computationally subtracts the effect of unwanted tissue, estimated with the smaller probe, from the effective contribution of both blood and unwanted tissue with the larger one. The method is validated by using simulated models and data from the full wave software CST Studio Suite across frequencies ranging from 1 to 10 GHz, achieving errors comparable to state-of-the-art techniques.

• Dang, Yu; Alam, Tanjir; Gebresilassie, Michael Cheffena & Kjelgård, Kristian Gjertsen (2024). Monopole-based Wideband Antenna with Embedded Band-notch for Applications in Upper UWB, 2024 International Conference on Electromagnetics in Advanced Applications (ICEAA). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9798350360974. doi: 10.1109/ICEAA61917.2024.10701784. Full text in Research Archive
• Rahman, Habibur; Recha, Adrian Miguel Llop; Fasciani, Stefano; Hogganvik, Pål Gunnar; Kjelgård, Kristian Gjertsen & Wisland, Dag Trygve Eckhoff (2024). Conure: Surrogate-based Artwork Generator for RFCMOS Integrated Inductors. IEEE International Symposium on Circuits and Systems proceedings. ISSN 0271-4302. doi: 10.1109/ISCAS58744.2024.10558598. Full text in Research Archive
• Amble, Magnus; Aunet, Snorre; Wisland, Dag Trygve Eckhoff & Kjelgård, Kristian Gjertsen (2023). Randomized Bulk-Voltages: A Countermeasure to Mask Side-Channel Leakage of CMOS Logic Gates. In Setti, Gianluca & Manganaro, M. (Ed.), Proceedings,2023 IEEE 66th International Midwest Symposium on Circuits and Systems (MWSCAS). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9798350302103. p. 708–712. doi: 10.1109/MWSCAS57524.2023.10406067. Full text in Research Archive
• Recha, Adrian Miguel Llop; Wisland, Dag Trygve Eckhoff; Lande, Tor Sverre & Kjelgård, Kristian Gjertsen (2023). Enhancing Measurement Specificity in Biological Samples with Differential Probing Analysis. In Soh, Ping Jack (Eds.), 2023 IEEE MTT-S International Microwave Biomedical Conference (IMBioC) Proceedings. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781665492171. p. 370–384. doi: 10.1109/IMBioC56839.2023.10304877. Full text in Research Archive
• Recha, Adrian Miguel Llop; Wisland, Dag Trygve Eckhoff; Lande, Tor Sverre; Kjelgård, Kristian Gjertsen & Cauwenberghs, Gert (2023). Wideband Proximity Coupling Sensor for Wrist Heart Rate Monitoring. In Chen, Jie (Eds.), 2023 IEEE Biomedical Circuits and Systems Conference (BioCAS). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9798350300260. doi: 10.1109/BioCAS58349.2023.10388551. Full text in Research Archive
• Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2022). valuation of UWB Radar Module for Snow Water Equivalent Monitoring. In Bozzi, Maurizio (Eds.), 2022 52nd European Microwave Conference (EuMC). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9782874870682. p. 87–90. doi: 10.23919/EuMC54642.2022.9924383. Full text in Research Archive
• Recha, Adrian Miguel Llop; Wisland, Dag Trygve Eckhoff; Lande, Tor Sverre & Kjelgård, Kristian Gjertsen (2022). Differential Analysis in Microwave Dielectric Probing for Transcutaneous Biomedical Sensing, 2021 51st European Microwave Conference (EuMC). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9782874870620. p. 845–848. doi: 10.23919/EuMC50147.2022.9784189. Full text in Research Archive
• Eriksrød, Jon Håvard; Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2022). Design of robust and low-loss 3-D printed double-ridged waveguide to microstrip transition. IET Microwaves, Antennas & Propagation. ISSN 1751-8725. 16(4), p. 224–232. doi: 10.1049/mia2.12233. Full text in Research Archive
• Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2021). Shielding of Tri-Patch Antenna Using 3D Printed Composite Carbon/PLA Absorber for Ultra Wideband Snow Radar Systems. In Shimoni, Michal (Eds.), 2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781665403696. p. 1039–1042. doi: 10.1109/IGARSS47720.2021.9554338. Full text in Research Archive
• Eriksrød, Jon Håvard; Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2020). Complex Dielectric Constant of Wet Snow Using Bi-Static Synthetic Aperture Radar. In Breinbjerg, Olav (Eds.), Proceedings of 14th European Conference on Antennas and Propagation (EuCAP 2020). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9788831299008. doi: 10.23919/EuCAP48036.2020.9135720. Full text in Research Archive
• Eriksrød, Jon Håvard; Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2019). A 3D-Printed Saddle reflector for upwards-looking Bi-static SAR Snow Radar. In Philippe, Eudeline (Eds.), 16th European Radar Conference, EuRAD 2019. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9782874870576. Full text in Research Archive
• Eriksrød, Jon Håvard; Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2019). In-situ Snowpack Inspection using Bi-static Radar, 2019 13th European Conference on Antennas and Propagation (EuCAP 2019). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781538681275. Full text in Research Archive
• Kjelgård, Kristian Gjertsen; Wisland, Dag T & Lande, Tor Sverre (2018). 3D Printed Wideband Microwave Absorbers using Composite Graphite/PLA Filament. In Suárez, Rodríguez Almudena (Eds.), 2018 48th European Microwave Conference (EuMC). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9782874870514. p. 859–862. doi: 10.23919/EuMC.2018.8541699. Full text in Research Archive
• Eriksrød, Jon Håvard; Kjelgård, Kristian Gjertsen; Tømmer, Mathias; Burkhart, John & Lande, Tor Sverre (2017). Bi-static environmental SAR radar imager. In Jari, Nurmi (Eds.), 2017 IEEE Nordic Circuits and Systems Conference (NORCAS): NORCHIP and International Symposium of System-on-Chip (SoC). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781538628447. doi: 10.1109/NORCHIP.2017.8124979. Full text in Research Archive
• Midtbøen, Vegard; Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2017). 3D printed horn antenna with PCB microstrip feed for UWB radar applications. In Perregrini, Luca (Eds.), 2017 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781538604809. doi: 10.1109/IMWS-AMP.2017.8247374. Full text in Research Archive
• Lauteslager, Timo; Tømmer, Mathias; Kjelgård, Kristian Gjertsen; Lande, Tor Sverre & Constandinou, T (2016). Intracranial heart rate detection using UWB radar, Biomedical Circuits and Systems Conference (BioCAS), 2016 IEEE. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781509029594. p. 119–122. doi: 10.1109/BioCAS.2016.7833739. Full text in Research Archive
• Tømmer, Mathias; Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2016). Body coupled wideband monopole antenna, 2016 Loughborough Antennas & Propagation Conference Proceedings. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781509007820. doi: 10.1109/LAPC.2016.7807483. Full text in Research Archive
• Mæland, Kenneth; Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2015). CMOS distributed amplifiers for UWB radar. In Almeida, Teresa Mendes de (Eds.), Circuits and Systems (ISCAS), 2015 IEEE International Symposium on. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781479983919. p. 1298–1301. doi: 10.1109/ISCAS.2015.7168879. Full text in Research Archive
• Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2015). A CMOS UWB K-band impulse radar receiver. In Gibson, Andrew (Eds.), 2015 12th European Radar Conference Proceedings. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9782874870415. p. 329–332. doi: 10.1109/EuRAD.2015.7346304. Full text in Research Archive
• Kjelgård, Kristian Gjertsen; Høvin, Mats Erling & Lande, Tor Sverre (2015). Body-coupled, wideband antennas. In Ghovanloo, Maysam (Eds.), 2015 IEEE Biomedical Circuits and Systems Conference (BioCAS) Proceedings. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781479972333. doi: 10.1109/BioCAS.2015.7348386. Full text in Research Archive
• Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2014). A differential K-band UWB transmitter for short range radar application with continuous running local oscillator. Progress In Electromagnetics Research C. 50, p. 1–9. doi: 10.2528/PIERC14032104. Full text in Research Archive
• Bjørndal, Øystein & Kjelgård, Kristian Gjertsen (2013). A new comb slow wave CPW for on chip area reduction and its RLCG model. In Yeom, Kyung-Whan; Kang, Kwang Yong & Lee, Moon-Que (Ed.), Microwave Conference Proceedings (APMC), 2013 Asia-Pacific. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781479914722. p. 404–406. doi: 10.1109/APMC.2013.6695161. Full text in Research Archive Show summary

  A compact low impedance transmission line in 90 nm CMOS is presented. The new comb slow wave grounded coplanar waveguide (comb-S-GCPW) is modeled, simulated and fabricated. Model is a simple and analytic RLCG equivalent circuit. The model agrees well with simulation and measurements in 90 nm CMOS. Measurements show a relative dielectric constant of 141 for a 12.3 Ω comb slow wave line, compared to 44.7 at 23.6Ω without fingers.

• Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2013). A K-band UWB receiver front-end with passive mixer in 90 nm CMOS. In Ren, Liu (Eds.), 2013 IEEE International Conference on Ultra-Wideband (ICUWB). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781479909698. p. 180–183. doi: 10.1109/icuwb.2013.6663844. Full text in Research Archive
• Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2012). A 26 GHz UWB CMOS IR-UWB Transmitter with On-chip Balun. In Lande, Tor Sverre (Eds.), Proceedings of the 30th Norchip Conference, NORCHIP12. IEEE Press. ISSN 9781467322225. p. 1–4. Full text in Research Archive
• Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2012). Design of 24 GHz UWB CMOS IR-UWB transmitter with on-chip balun. In James, Rautio (Eds.), 2012 IEEE International Conference on Ultra-Wideband (ICUWB). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781457720314. p. 320–323. doi: 10.1109/icuwb.2012.6340503. Full text in Research Archive
• Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2011). A K-band UWB CMOS pulse-mode radar transmitter. In Sawan, Mohamad (Eds.), 2011 18th IEEE International Conference on Electronics, Circuits and Systems (ICECS). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781457718458. p. 500–503. doi: 10.1109/icecs.2011.6122322. Full text in Research Archive
• Ramstad, Jan Erik; Kjelgård, Kristian Gjertsen; Nordbø, Bård Eirik & Søråsen, Oddvar (2009). RF MEMS front-end resonator, filters, varactors and a switch using CMOS-MEMS process. In Bourouina, Tarik; Courtois, Bernard; Ghodssi, Reza; Karam, Jean Michel; Soma, Aurelio & Yang, Hsiharng (Ed.), Design, Test, Integration and Packaging of MEMS/MOEMS 2009. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9782355000096. p. 170–175. Full text in Research Archive Show summary

  The paper describes the design of multiple RF MEMS front-end components that could replace off-chip units in future transceivers. The components can effectively be combined and cofabricated with CMOS circuitry. A CMOS-MEMS approach is used, which means that the microelectromechanical parts are made by multi-layer structures in a standard CMOS process. The ASIMPS procedure offered by CMP uses the CMOS processing at STMicroelectronics, and a simple post-CMOS release-etching step is performed at Carnegie Mellon University, USA. The paper presents a resonator, resonating filters, electrothermally operated varactors and an experimental switch. The components are modeled and simulated by using CoverntorWare FEM software. A test chip is currently in production.

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• Nurmi, Jari; Wisland, Dag Trygve Eckhoff; Aunet, Snorre & Kjelgård, Kristian Gjertsen (2022). Proceedings, 2022 IEEE Norcas Conference. IEEE (Institute of Electrical and Electronics Engineers). ISBN 9798350345506. 200 p. Full text in Research Archive
• Nurmi, Jari; Wisland, Dag Trygve Eckhoff; Aunet, Snorre & Kjelgård, Kristian Gjertsen (2021). Proceedings, 2021 IEEE Nordic Circuits and Systems Conference (NORCAS). IEEE (Institute of Electrical and Electronics Engineers). ISBN 9781665407120. 220 p. Full text in Research Archive
• Nurmi, Jari; Wisland, Dag T; Aunet, Snorre & Kjelgård, Kristian Gjertsen (2020). Proceedings, Sixth IEEE Nordic Circuits and Systems Conference (NorCAS 2020). IEEE (Institute of Electrical and Electronics Engineers). ISBN 9781728192260. 205 p. Full text in Research Archive Show summary

  On behalf of the Organizing Committee, we would like to welcome all of you to the Sixth IEEE Nordic Circuits and Systems Conference (NorCAS 2020). The conference is a merge of the well-established conferences NORCHIP and the International Symposium on System-on-Chip (SoC). We have a high-quality program with keynotes and papers to be presented. Research covering a wide range of topics within circuits and systems in the digital, analog and mixed domains will be presented. From in total 58 papers submitted, 29 papers were selected for oral presentation in the virtual conference, yielding exactly 50% acceptance rate. There will be four invited speakers who will share their view on emerging key technologies in the circuits and systems field. In the opening session Prof. An-Yeu (Andy) Wu from National Taiwan University will discuss compressive sensing and compressive analytics. Later in the afternoon Prof. Alberto Bosio from ICL, France, will give insights to approximate computing and, in particular, testing of it. In the second morning, Prof. Tim Constandinou from University College London, UK, will present his talk on “Future Human: Merging Minds and Machines.“ The final talk is given by Prof. Alexander Wyglinsky from Worchester Polytechnic Institute, USA, introducing an educational view to Software-Defined Radio. We would like to forward great thanks to IEEE Circuits and Systems Society (CAS) for financial co-sponsoring of the conference. Thanks also to Tampere University and University of Oslo for the efforts on the congress office and virtual platform. We are also thankful to all the Program Committee members and reviewers who have put time and effort into reviewing the submitted papers. Moreover, we are grateful to the NorCAS steering committee for helpful advice and their contribution in the paper selection process. We hope that you will enjoy your time in the virtual conference. We wish you an inspiring conference where your knowledge is increased and friendships are both established and strengthened.

• Ulvestad, Emil; Kjelgård, Kristian Gjertsen; Khanshan, Tohid Moradi; Wisland, Dag T & Lande, Tor Sverre (2018). High-speed Sampling System in CMOS. IEEE (Institute of Electrical and Electronics Engineers). ISBN 9781538676561. 4 p. Full text in Research Archive
• Khanshan, Tohid Moradi; Kjelgård, Kristian Gjertsen; Ulvestad, Emil; Wisland, Dag T & Lande, Tor Sverre (2018). CMOS photosensors for LIDAR. IEEE (Institute of Electrical and Electronics Engineers). ISBN 9781538676561. 4 p. Full text in Research Archive

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• Rahman, Habibur; Recha, Adrian Miguel Llop; Wisland, Dag Trygve Eckhoff & Kjelgård, Kristian Gjertsen (2024). Phase-Tunable CMOS Hybrid Coupler for Dual-Mode Reflection Analysis. Full text in Research Archive
• Amble, Magnus; Aunet, Snorre; Wisland, Dag Trygve Eckhoff & Kjelgård, Kristian Gjertsen (2023). Randomized Bulk-Voltages: A Countermeasure to Mask Side-Channel Leakage of CMOS Logic Gates. Full text in Research Archive
• Kjelgård, Kristian Gjertsen; Nurmi, Jari & Wisland, Dag Trygve Eckhoff (2021). Welcome to NORCAS 2021. IEEE Xplore Digital Library. doi: 10.1109/NorCAS53631.2021.9599644. Full text in Research Archive
• Hoel, Karina Vieira; Kristoffersen, Stein; Moen, Jonas; Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2016). Broadband Antenna Design Using Different 3D Printing Technologies and Metallization Processes. Full text in Research Archive
• Akre, Erlend; Aunet, Snorre; Wisland, Dag Trygve Eckhoff & Kjelgård, Kristian Gjertsen (2023). Ultra Low Power Digital Oscillator with Dynamic Leakage Suppression and compensation In 65nm BULK CMOS and 22nm FDSOI. Universitetet i Oslo, Fysisk Institutt. Full text in Research Archive
• Amble, Magnus; Kjelgård, Kristian Gjertsen; Wisland, Dag Trygve Eckhoff & Aunet, Snorre (2023). Cryptographic hardware resistant to Leakage-Based Differential Power Analysis Attacks. Universitetet i Oslo. Full text in Research Archive

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