A flip-chip-packaged and fully integrated 60 GHz CMOS micro-radar sensor for heartbeat and mechanical vibration detections

Abstract

A 60 GHz micro-radar in 90 nm CMOS for non-contact vital sign and small vibration detections was designed and tested. A quadrature receiver embedded in the indirect up-and down-conversion architechture solves the null detection point issue and increases the robustness of the millimeter wave system. In the 60 GHz core, lumpedelement-modeled passive components are extensively used to achieve a compact layout (0.73 mm 2 ), and a 36 dB downconversion gain at 55 GHz. Using low-cost single-patch PCB antennas, flip-chip packaging of the CMOS chip demonstrates high level of system integration. First pass success is achieved as the human heartbeat and a small mechanical vibration with a displacement of 20 μm can be detected at 0.3 m away. With a roughly one-tenth patch antenna size compared to previously reported works, the 60 GHz CMOS integrated micro-radar can be readily embedded in various portable devices to detect vary small vibrations and used for many applications.Index Terms -CMOS, Doppler radar, flip chip, millimeter wave integrated circuits, medical signal detection, patch antennas, sensor systems, frequency measurement.

Ultra-Wide Patch Antenna Array Design at 60 GHz Band for Remote Vital Sign Monitoring with Doppler Radar Principle

“…In the recent couple of decades, a significant amount of research has been conducted to improve the accuracy of the RVSM by employing various techniques including distance and frequency optimization [13][14][15][16][17][18], robust signal processing methods [19][20][21], breath holding for HR detection and so on [22][23][24][25][26][27][28]. However, most of the reported practical work is based on Doppler radars working at lower microwave (MW) frequency bands around 2.4, 5.8 and 10 GHz where the wavelength resolution of the electromagnetic wave is low and therefore the accuracy of the vital signs detection, especially the HR, remained challenging [23].…”

“…However, most of the reported practical work is based on Doppler radars working at lower microwave (MW) frequency bands around 2.4, 5.8 and 10 GHz where the wavelength resolution of the electromagnetic wave is low and therefore the accuracy of the vital signs detection, especially the HR, remained challenging [23]. Secondly, the radar antenna systems at the mentioned low MW frequencies are quite bulky which may abstain to be integrated with modern real-life compact devices like smart phones and tablets [23]. Ka band frequencies have also been investigated for RVSM to enhance the RVSM sensors sensitivity due to comparatively shorter wavelength at Ka frequencies [24][25][26].…”

“…In the recent years, millimetre-wave (MMW) frequencies (30-300 GHz) have drawn a remarkable research interest for RVSM implications [23,[27][28][29][30][31][32][33][34][35]. The main motives of RVSM at MMW frequencies include (i) improvement in the detection accuracy by employing shorter wavelength of the signal, (ii) smaller form factor for the device compactness and (iii) possibility of more subject focused signal transmission and reception to avoid the interference from the unwanted side reflections [22,[33][34][35].…”

“…The antenna should be designed in such a way that it only focuses the radiation beam on the subject [22] and should have an adequate gain to maintain a required signal to noise ratio [31]. Microstrip patch antennas are thought to better option for compact MMW sensors due to their embedment with on-chip devices, low profile, low cost and ability to make array to attain high antenna gain [23,[30][31][32]. In [30], conventionally designed microstrip patch antennas are integrated with on-chip micro-radar system for RVSM.…”

A Compact Ka-Band Doppler Radar Sensor for Remote Human Vital Signal Detection

“…Recently, the demand for short-range Doppler radar sensors has increased because they can be applied to an enormous range of applications, such as healthcare bioradar and motion detectors [1]～ [6]. At present, most heartbeat and respiration rate monitoring sensors have to be attached to the human body directly.…”