건국대학교 밀리미터파 집적시스템 연구실
밀리미터파 집적시스템 연구실에서는 아날로그, RF, 초고주파에 이르는 다양한 주파수 대역 IC기술과 전자기파 특성기반 다양한 응용 시스템 연구를 수행합니다. 모든 분들의 방문을 환영합니다.
위치: 공학관 321-1호 (교수 연구실), 신공학관 1117호 (학생 연구실), KU기술혁신관 607호 (교원 창업기업)
OUR LATEST RESEARCHES
A D-band Two-Way Differential Power Divider on 65-nm CMOS Process
A CMOS two-way differential power divider is proposed to reduce the insertion loss (IL) and size in the D-band. The power distribution is achieved using a low-loss differential power divider with a capacitive loading structure, without modifying the matching network of the unit devices. In addition, the degradation of the IL due to the parasitic inductance of groundings is made negligible by using the virtual ground of the differential structure. The impedance of the differential-mode transmission line (TL), which is half that of the single-ended line, is designed in the impedance range achievable in the bulk CMOS process, utilizing capacitive loading techniques. The 3-D electromagnetic (EM) simulation results of a two-way power divider show a low IL within 0.35 dB at 110–170 GHz. The proposed power divider achieves a measured minimum IL of 0.32 dB at 160 GHz with a core size of 0.0075 mm2.
Heart Rate Extraction Technique with Mitigation of Respiration Harmonic for Bio Radar Sensors
A methodology is proposed to effectively extract heart rate from bio-radar sensors based on radar technology. Heart and respiration rates are extracted separately by calculating intrinsic mode functions (IMFs) obtained from the empirical mode decomposition (EMD) method applied to the received radar signals. Due to the frequency difference between respiration and heartbeat signals, it is possible to selectively generate respiration harmonics by exploiting the characteristics present in different IMFs. These harmonics are used to eliminate the noise caused by respiratory activity around the heartbeat signal, thereby improving the signal-to-noise ratio of heartbeat detection. In the experiment utilizing the in-house 5.8 GHz continuous wave radar sensor, the proposed technique exhibited an average heart rate extraction accuracy of 97.5% for the stationary subjects at a distance of 1 m, in comparison to the reference electrocardiogram sensor. Compared to the conventional method using only fast Fourier transform and the EMD-based method without respiration harmonic rejection, the proposed technique achieved an average noise suppression of 22.3 dB and 20.3 dB around the heart rate signal, respectively. In addition, the proposed technique demonstrated the potential to mitigate the effects of random body motion noise, achieving an average heart rate accuracy of 92.8% when applied to the walking subject at a speed of 2 km/h.