Researches & Projects | Millimeter-wave Integrated Systems Lab. at Konkuk University

1. D-Band ICs for Integrated Sensing and Communication

Key D-band circuit technologies have been developed for integrated sensing and communication (ISAC) transceiver front-ends. The developed technologies include a ×6 frequency multiplier based on harmonic-mode analysis for efficient high-frequency signal generation, a vector-modulator-based D-band phase shifter for beam-steering phase control, and transformer-coupled differential power dividers/combiners for low-loss signal distribution and combining.

These circuit building blocks provide a foundation for highly integrated D-band transceiver architectures targeting simultaneous communication and sensing functions.

2. Sub-THz Circuits for Non-Destructive See-Thru Imaging Systems

A plasmonic detector IC was developed using an LC-based impedance-enhancement structure to simultaneously improve voltage responsivity and noise-equivalent power (NEP). A modular array architecture based on a 0.25-μm CMOS process was implemented by extending 2 × 2 unit detector cells to an 8 × 8 array, achieving an average voltage responsivity of 214.9 kV/W.

The detector array enabled raster-scan imaging and successfully recognized sub-wavelength patterns with approximately 1-mm feature size, validating its applicability to nondestructive inspection and foreign-object detection.

1. Robust Radar Signal Processing for Noncontact Vital-Sign Detection

We have developed robust radar signal-processing techniques for noncontact vital-sign detection based on the analysis of EM-wave reflection characteristics. To improve detection performance under noisy and interference-prone environments, mode-decomposition-based component separation was applied to mixed radar signals containing noise, enabling more reliable extraction of physiological signal components. For beam-steering radar data, highly correlated signal components were extracted and compared with a Bessel-function-based physical model. This approach enabled the selection of physically plausible heartbeat candidates, improving the reliability of heart-rate estimation in practical measurement conditions.

The proposed radar signal-processing techniques have been validated in various real-world environments, including offices, hospitals, and vehicles, demonstrating their potential for clinically relevant noncontact monitoring applications.

2. Multi-Mode Radar Signal Fusion for Robust Indoor Sensing

A multi-mode radar signal-fusion technique was developed to combine the complementary advantages of different radar operation modes while compensating for their individual physical limitations. By integrating reliable range information with continuous motion information, the proposed approach enables stable indoor radar sensing in practical environments.

Signal-processing and fusion algorithms were developed to reduce range-estimation uncertainty caused by indoor clutter, multipath reflections, and interference. In the 5.8-GHz ISM band, the system demonstrated signal-processing-assisted discrimination of two closely spaced targets with sub-meter separation, despite the limited 150-MHz bandwidth.

3. Edge-Compatible Fall Detection using Continuous-Wave Radar Sensors

A physics-based fall-detection algorithm was developed using continuous-wave radar sensor signals. The method sequentially combines time-domain and frequency-domain analyses to reduce computational complexity, enabling reliable fall detection without dependence on high sampling rates or large training datasets.

Through more than 1,000 controlled laboratory experiments, the proposed technique achieved 100% detection accuracy and a 0% false-alarm rate, demonstrating its suitability for edge-device-based fall monitoring applications.

1. Signal-Integrity Analysis of mmWave Chip-to-LTCC Packaging

A millimeter-wave chip-to-LTCC packaging structure was analyzed in terms of signal-line length, bump interconnects, and impedance-matching characteristics. The study identified that securing a substrate signal-line length of at least 1.5 mm is necessary to mitigate unstable reflection-loss behavior caused by excessively short transmission paths.

The results also demonstrated that impedance-matching structures implemented on the LTCC substrate side can effectively suppress reflection along the full signal path, confirming the critical role of substrate-side matching in stable millimeter-wave package design.

2. Optimization-Based Parameter Extraction for Fast SI Analysis

An automated parameter-extraction method was developed to accelerate signal-integrity (SI) analysis of semiconductor packaging structures. Using a Python-based stochastic hill-climbing algorithm, complex interconnects such as bond wires and lead frames were efficiently modeled through cost-function-based random perturbation and optimization.

The extracted equivalent models showed strong frequency-response agreement with 3D electromagnetic simulation results, validating the proposed method as a fast and resource-efficient approach for semiconductor packaging SI analysis.

3. Compact 3D Impedance Matching for 60-GHz Multi-Channel Modules

A 3D vertical-stub impedance-matching technique was proposed to mitigate interconnect-induced impedance mismatch, power-transfer degradation, and inter-channel interference in 60-GHz ISM-band multi-channel modules. By using multilayer substrates and via structures, the proposed method vertically distributes the required reactance and overcomes the area and coupling limitations of conventional planar matching structures.

3D electromagnetic simulation of a two-channel IC-to-LTCC substrate model verified bidirectional impedance matching without additional lateral area, demonstrating its suitability for compact millimeter-wave packaging.

PROJECTS

<On-Going Projects>

2026.03.01. - 2031.02.28. 한국연구재단(National Research Foundation of Korea, NRF) 개인기초연구(핵심연구), No. RS-2026-25476796, 주파수 대역폭과 파장 한계를 극복하는 고해상도 밀리미터파 CMOS IC기반 영상 시스템 기술(CMOS IC-Based High-Resolution Millimeter-Wave Imaging System Technologies Overcoming Bandwidth and Wavelength Limitations) <연구책임자>
2026.03.01. - 2031.02.28. 한국산업기술진흥원(Korea Institute for Advancement of Technology, KIAT) 산업혁신인재성장지원(교육훈련)사업, 반도체핵심IP설계전문인력양성 (Training Program for Semiconductor Core IP Design Specialists) <고속인터페이스 및 커넥티비티 분야 참여연구자>
2023.07.01. - 2030.02.28. 한국연구재단(NRF) 지역선도연구개발센터(Regional Leading Research Center, RLRC), No. RS-2023-00219725, 라이프로그용 멀티모달 언택트센싱 선도연구센터(Development of Multimodal Untact Sensing for Life-Logging) <그룹3 책임연구자>
2024.04.01.-2028.12.31. 정보통신기획평가원(Institute for Information & Communications Technology Planning & Evaluation, IITP) 차세대 네트워크(6G) 산업기술개발사업 , No. RS-2024-00397336, 6G Upper-mid Band 통신단말핵심 모듈 및 부품기술 개발(Development of 6G Upper-mid Band communication terminal core module and component technology) <위탁기관 책임자>
2019.04.01. - 2026.12.31. 정보통신기획평가원(IITP) 전파특화연구센터(Radio Research Center), No. 2019-0-00138, 스마트 환경 구축을 위한 지능형 레이다 플랫폼 기술 개발(Development of Intelligent Radar Platform Technology for Smart Environments) <참여기관 책임자>

2021.03.01. - 2026.02.28. KIAT 산업혁신인재성장지원, No. P0017011, 차세대 시스템 반도체설계 전문인력 양성사업 (Next-Generation System Semiconductor Design Engineer Development Program)
2023.04.01. - 2025.12.31. 한국산업기술평가관리원(Korea Evaluation Institute of Industrial Technology, KEIT) 시장선도를위한한국주도형K-Sensor기술개발사업, No. RS-2023-00232390, 4-D 이미지 레이다용 단일칩 레이다 센서 개발(Development of Single Chip Radar Sensor for 4-D Image Radar)
2021.12.01. - 2024.11.30. KIAT 국제공동기술개발사업, No. P0019789, Flexible 필름을 이용한 CMOS 서브 테라헤르츠 AiP 개발 (Development of a CMOS sub-terahertz AiP(Antenna-in-Package) using a flexible film)
2023.04.01. - 2023.12.31. IITP 한국전자통신 연구원(Electronics and Telecommunications Research Institute, ETRI) 위탁연구, No. 2021-0-00938, 6G용 초광대역 고출력/고이득 증폭기 회로 고도화 연구 (A Study of the Circuit Topology with High-Power and High-Efficiency for the 6G Applications)
2021.03.01. - 2024.02.28. NRF 개인기초연구(중견연구), No. 2021R1A2C2004356, 공간전력결합과 편파방향제어/검출이 가능한 밀리미터파 송수신단 기술 연구(A Study on Millimeter-wave Transceiver for Spatial Power Combining and Polarization Control & Detection)
2022.06.01. - 2022.12.31. IITP 한국전자통신 연구원(ETRI) 위탁연구, No. 2021-0-00938, 6G용 초광대역 저전력 전력증폭기 회로 구조 연구 (A Study of the Circuit Topology for Wideband Power Amplifiers in the 6G Applications)
2021.04.01. - 2022.12.31. KIAT 지역스타기업육성사업, No. S3057227, 영상분석 및 5.8GHz 저전력 속도센서 신규 개발을 통한 다변 환경 감응 지능형 교통 표지판 개발 (Development of Intelligent Traffic Sign Board that responds to multivariate environments with video analysis function and new 5.8GHz low power speed sensor)
2019.05.01. - 2022.12.31. IITP ETRI 위탁연구, No. 2019-0-00008, 밀리미터파 송신단 센싱 기술(Millimeter-wave Transmitter Sensing Techniques)
2018.07.01. - 2022.12.31. IITP Grant R&D, No. 2018-0-00711, 준 테라헤르츠 실시간 영상시스템을 위한 CMOS 플라즈몬 검출기 대면적 배열구조 연구(A Study on Large-scale Array of CMOS Plasmon Detectors for Real-time Sub-Terahertz Imaging System)
2017.03.01. - 2021.02.28. NRF 개인기초연구(신진연구), No. 2017R1C1B2002285, 에너지 검출특성기반 고감도 밀리미터파 전력/위상차 검출기술 연구 (Highly Sensitive Millimeter-wave Power/Phase Difference Detection based on Energy Detection Characteristics)
2019.06.01. - 2020.05.31. 한국산학협회(Korea Sanhak Foundation, KSF) 산학공동과제, 운전자 및 동승자 모니터링용 레이더센서 및 전자기파 특성연구(Radar Sensors and EM-wave Characteristics for Monitoring Vital Signs of a Driver and Passengers)
2019.02.01. - 2019.11.30. 한국전기연구원(Korea Electrotechnology Research Institute, KERI) 위탁연구, 고출력 초고주파 서큘레이터 소형화 기술연구(Study on the Miniaturization of the High-powered High-frequency Circulator)
2018.02.01. - 2018.11.30. KERI 위탁연구, 전력측정기반 고출력 초고주파신호 위상차측정기술연구(Study on Measurement Method for Phase Differences in High-frequency High-power Signals based on Power Detection)
2017.12.01. - 2018.08.30. 중소벤처기업부(Ministry of SMEs and Startups), 정밀 GPS 시스템을 위한 H/W 및 S/W 개발(H/W and S/W Development for Highly Accurate Global Positioning System)
2017.04.18. - 2018.04.17. 한국산업단지공단(Korea Industrial Complex Corporation, KICOX) 현장맞춤형 기술개발사업, 물체감지용 4-channel 레이더센서 개발(4-channel Radar Sensor Development for Object Detection)