Kristian Gjertsen Kjelgård

• 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 979-8-3503-0210-3. p. 708–712. doi: 10.1109/MWSCAS57524.2023.10406067.
• 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 conference proceedings. ISSN 979-8-3503-0026-0. doi: 10.1109/BioCAS58349.2023.10388551.
• 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 conference proceedings. ISSN 978-1-6654-9217-1. p. 370–384. doi: 10.1109/IMBioC56839.2023.10304877.
• 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 conference proceedings. ISSN 978-2-87487-068-2. p. 87–90. doi: 10.23919/EuMC54642.2022.9924383.
• Llop Recha, Adrian Miguel; 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 conference proceedings. ISSN 978-2-87487-062-0. p. 845–848. doi: 10.23919/EuMC50147.2022.9784189.
• 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.
• 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 conference proceedings. ISSN 978-1-6654-0369-6. p. 1039–1042. doi: 10.1109/IGARSS47720.2021.9554338.
• 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 978-88-31299-00-8. doi: 10.23919/EuCAP48036.2020.9135720.
• 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 978-2-87487-057-6.
• 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.
• Kjelgård, Kristian Gjertsen; Wisland, Dag T & Lande, Tor Sverre (2018). 3D Printed Wideband Microwave Absorbers using Composite Graphite/PLA Filament . In Almudena Suárez, Rodríguez (Eds.), 2018 48th European Microwave Conference (EuMC). IEEE conference proceedings. ISSN 978-2-87487-051-4. p. 859–862. doi: 10.23919/EuMC.2018.8541699.
• 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 conference proceedings. ISSN 978-1-5386-0480-9. doi: 10.1109/IMWS-AMP.2017.8247374.
• 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 conference proceedings. ISSN 978-1-5386-2844-7. doi: 10.1109/NORCHIP.2017.8124979.
• 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 conference proceedings. ISSN 978-1-5090-2959-4. p. 119–122. doi: 10.1109/BioCAS.2016.7833739.
• Tømmer, Mathias; Kjelgård, Kristian Gjertsen & Lande, Tor Sverre (2016). Body coupled wideband monopole antenna, 2016 Loughborough Antennas & Propagation Conference Proceedings. IEEE conference proceedings. ISSN 978-1-5090-0782-0. doi: 10.1109/LAPC.2016.7807483.
• 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 conference proceedings. ISSN 978-1-4799-8391-9. p. 1298–1301. doi: 10.1109/ISCAS.2015.7168879.
• 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 conference proceedings. ISSN 978-2-87487-041-5. p. 329–332. doi: 10.1109/EuRAD.2015.7346304.
• 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 conference proceedings. ISSN 978-1-4799-7233-3. doi: 10.1109/BioCAS.2015.7348386.
• 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. ISSN 1937-8718. 50, p. 1–9. doi: 10.2528/PIERC14032104.
• 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 conference proceedings. ISSN 978-1-4799-0969-8. p. 180–183. doi: 10.1109/icuwb.2013.6663844.
• 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 conference proceedings. ISSN 978-1-4799-1472-2. p. 404–406. doi: 10.1109/APMC.2013.6695161. 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 (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 978-1-4673-2222-5. p. 1–4.
• 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 conference proceedings. ISSN 978-1-4577-2031-4. p. 320–323. doi: 10.1109/icuwb.2012.6340503.
• 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 conference proceedings. ISSN 978-1-4577-1845-8. p. 500–503. doi: 10.1109/icecs.2011.6122322.
• 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. 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 conference proceedings. ISBN 979-8-3503-4550-6. 200 p.
• 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 978-1-6654-0712-0. 220 p.
• Nurmi, Jari; Wisland, Dag T; Aunet, Snorre & Kjelgård, Kristian Gjertsen (2020). Proceedings, Sixth IEEE Nordic Circuits and Systems Conference (NorCAS 2020). . IEEE conference proceedings. ISBN 978-1-7281-9226-0. 205 p. 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.

• Moradi Khanshan, Tohid; Kjelgård, Kristian Gjertsen; Ulvestad, Emil; Wisland, Dag T & Lande, Tor Sverre (2018). CMOS photosensors for LIDAR. IEEE conference proceedings. ISBN 978-1-5386-7656-1. 4 p.
• Ulvestad, Emil; Kjelgård, Kristian Gjertsen; Moradi Khanshan, Tohid; Wisland, Dag T & Lande, Tor Sverre (2018). High-speed Sampling System in CMOS. IEEE conference proceedings. ISBN 978-1-5386-7656-1. 4 p.

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• 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.
• Kjelgård, Kristian Gjertsen; Nurmi, Jari & Wisland, Dag Trygve Eckhoff (2021). Welcome to NORCAS 2021. IEEE Xplore Digital Library. doi: 10.1109/NorCAS53631.2021.9599644.
• 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.
• 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.
• 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. Show summary

  As cryptographic encryption algorithms have progressed in complexity, adversaries have looked to other means of accessing encrypted secret data than traditional cryptanalysis. One such alternative method of intrusion is through side-channel analysis, where physical properties of a cryptographic circuit are analyzed to reveal sensitive data. This thesis presents analyses of countermeasures against side-channel analysis based on variations in the power consumption of a circuit. A trend seen in the advancement of Complementary Metal–Oxide–Semiconductor(CMOS) technology is an increase in static power consumption. In the context of cryptographic circuits, this aspect of the power consumption has proven to contain information about sensitive data processed by the circuit, making it a potential attack vector for an adversary. Three gate-level countermeasures against leakage power analysis attacks are proposed in this thesis. Two of which are logic styles based on the equalization of a logic gate’s power consumption between input combinations, coined Octuple logic and Quadruple Dual-Pulldown Logic (QDPL). Both of these countermeasures expand on the concept of a countermeasure from the literature called Exhaustive Logic Balancing (ELB). The third proposed countermeasure is a current-masking scheme that introduces input-independent noise in the power consumption through periodically randomizing the voltage on the bulk-terminals of the logic gate. Combining such a logic style with the bulk-voltage masking scheme lowers the possible signal-to-noise ratio obtainable by an adversary by both adding additional noise to, and by lowering the data-dependency in, a circuits power consumption. Preliminary experiments showed that the masking scheme is able to modulate the static current of a ELB NAND gate within an interval where the highest current is six times larger than the lowest current. Subsequently, rough estimates show that if signal averaging analyses are conducted on a register implemented in QDPL, the mask could make the analyses require over 800000 additional signal measurements, compared to when no mask is applied, to find a one-bit hamming weight difference in the register’s static current.

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