Hsin Chih Kuo

60-GHz Millimeter-Wave Life Detection System (MLDS) for Noncontact Human Vital-Signal Monitoring

A first reported experimental study of a 60 GHz millimeter-wave life detection system (MLDS) for noncontact human vital-signal monitoring is presented. This detection system is constructed by using V-band millimeter-wave waveguide components. A clutter canceller is implemented in the system with an adjustable attenuator and phase shifter. It performs clutter cancellation for the transmitting power leakage from the circulator and background reflection to enhance the detecting sensitivity of weak vital signals. The noncontact vital signal measurements have been conducted on a human subject in four different physical orientations from distances of 1 and 2 m. The time-domain and spectrum waveforms of the measured breathing and heartbeat are presented. This prototype system will be useful for the development of the 60-GHz CMOS MLDS detector chip design.

Low-Voltage

This paper presents the design of a direct-injection divide-by-3 frequency divider operating at the K -band. The divider is implemented in a 0.18- μm CMOS process. The measured free-running frequency of the divider is 7.96 GHz. By utilizing a floating-source differential injector and without a varactor tuning in the divider core, the total locking range is 3.2 GHz with a power consumption of 8.28 mW from a supply voltage of 0.9 V. The total power consumption of the buffers is 9.54 mW from a supply voltage of 1.8 V. The measured phase noise of the divider is -141.3 dBc/Hz at 1-MHz offset when the input referred signal with a phase noise of -132.8 dBc/Hz at 1-MHz offset from 24 GHz. The phase-noise difference of 8.5 dB is close to the theoretical value of 9.5 dB for division-by-3. The output power of the divider is more than -11 dBm over the whole locking range.

K

This paper presents a 60-GHz CMOS direct-conversion Doppler radar RF sensor with a clutter canceller for single-antenna noncontact human vital-signs detection. A high isolation quasi-circulator (QC) is designed to reduce the transmitting (Tx) power leakage (to the receiver). The clutter canceller performs cancellation for the Tx leakage power (from the QC) and the stationary background reflection clutter to enhance the detection sensitivity of weak vital signals. The integration of the 60-GHz RF sensor consists of the voltage-controlled oscillator, divided-by-2 frequency divider, power amplifier, QC, clutter canceller (consisting of variable-gain amplifier and 360 ° phase shifter), low-noise amplifier, in-phase/quadrature-phase sub-harmonic mixer, and three couplers. In the human vital-signs detection experimental measurement, at a distance of 75 cm, the detected heartbeat (1-1.3 Hz) and respiratory (0.35-0.45 Hz) signals can be clearly observed with a 60-GHz 17-dBi patch-array antenna. The RF sensor is fabricated in 90-nm CMOS technology with a chip size of 2 mm×2 mm and a consuming power of 217 mW.

-Band Divide-by-3 Injection-Locked Frequency Divider With Floating-Source Differential Injector

This paper presents a 60GHz high-isolation CMOS single-pole double-throw (SPDT) transmitter/receiver (T/R) switch fabricated with TSMC standard 90-nm 1P9M CMOS technology. A low insertion loss and high linearity are achieved by using the body-floating technique. The leakage cancellation technique is used to increase the isolation between the transmitter and receiver ports. The top metal (M9) is mainly adopted for designing signal paths and the microstrip-line matching elements. In order to minimize the substrate loss, the first metal (M1) as the ground plane is used in this design. The measured results show the insertion loss from the transmitter port to the antenna port is less than 3.5 dB, and the isolation between the transmitter and receiver ports is higher than 28 dB from 57 to 64GHz. At the center frequency of 60GHz, the port isolation is higher than 34 dB and the input 1-dB compression point (IP1dB) is +6.9 dBm.

A Fully Integrated 60-GHz CMOS Direct-Conversion Doppler Radar RF Sensor With Clutter Canceller for Single-Antenna Noncontact Human Vital-Signs Detection

This paper presents a 60-GHz CMOS direct-conversion Doppler radar RF sensor with a quasi-circulator (QC) and a clutter canceller circuit for single-antenna noncontact human vital-signs detection. A high isolation QC is designed to provide better detection sensitivity for the tiny vital-signs detection for the single-antenna Doppler radar architecture. The clutter canceller performs cancellation for the transmitting leakage power from the circulator and the background reflection clutter to enhance the detection sensitivity of weak vital signals. The measurement shows that the total transmitting power is 3 dBm while the conversion gain of the sub-harmonic receiver is 10.5 dB. In the human vital-signs detection measurement, at a distance of 75 cm, the detected heartbeat (1-1.3 Hz) and respiratory (0.35-0.45 Hz) signals can be clearly observed. The RF sensor is fabricated in 90-nm technology with a chip size of 2 mm × 2 mm and a consuming power of 217 mW. The presented CMOS vital-signs Doppler radar RF sensor will be very useful for the wireless remote physiological monitoring healthcare system and the tiny vibrations detection applications.

A high-isolation 60GHz CMOS transmit/receive switch

A new injector topology is adopted for the design of a 60-GHz CMOS divide-by-5 injection-locked frequency divider (ILFD). The topology is based on a distributed-element harmonic termination by an open-stub structure connected to the floating source end of the differential injection pair. With this topology together with an N-MOS cross-coupled oscillator core, the supply voltage and power consumption of the divider can be greatly reduced. A test circuit is implemented in a 90-nm CMOS process. With the added λ/4 open stub, the simulated frequency locking range of the designed ILFD with the distributed-element harmonic termination scheme has been greatly extended over 70%. The measured power consumption is 3.75 mW at a supply voltage of 0.6 V and the locking range is 4.1 GHz. A good figure of merit (FOM) of 69.4 is achieved.

A 60-GHz CMOS direct-conversion Doppler radar RF sensor with clutter canceller for single-antenna noncontact human vital-signs detection

This paper presents a 60-GHz CMOS balanced power amplifier (PA) with miniaturized quadrature hybrids using 90-nm CMOS technology. To improve the output power and provide an area-efficient solution for the balanced PA design, a compact 3-dB quadrature hybrid constructed by a broadside-coupled scheme is employed as a low-insertion-loss power splitter/combiner. With a very short effective guided wavelength of 0.072 λg, the simulated insertion loss and phase difference of the quadrature hybrids are better than 0.5 dB and 90° ± 0.2°, respectively. The designed PA reaches a power gain exceeding 13.2 dB and a saturation power of 10.7 dBm with a power-added efficiency (PAE) more than 9 % at 60 GHz. The power consumption of the PA is 109 mW at a 1.2 V supply voltage. The chip size is 0.68 mm2.

60GHz CMOS divide-by-5 injection-locked frequency divider with an open-stub-loaded floating-source injector

A 60-GHz down-converting dual-gate mixer, fabricated in the 0.13-μm CMOS process, for WPAN applications is presented. The mixer utilizes the dual-gate topology and adds a buffer to avoid loading effects. A good agreement between simulation and measurements is observed. The mixer exhibits a conversion loss of 2.7 dB, input 1-dB compression point of −8 dBm at RF of 60 GHz, IF of 5 GHz and LO power of 0 dBm. The total power consumption is 16.8 mW, 7.2 mW for the core mixer and 9.6 mW for the buffer.

Design of 60-GHz 90-nm CMOS balanced power amplifier with miniaturized quadrature hybrids

Microwave/millimeter-wave Doppler sensor systems with various operating frequency for noncontact human vital-signs sensing have been reported extensively. To investigate the frequency effect on the detection performance of the vital signs, the muscle sphere is used to emulate the human heart organ to compute the scattering field of the incident wave radiated from the Doppler sensor and calculate the radar cross section (RCS) of different frequency. A pig heart is used in the experimental measurement to measure the RCS and compare with the computed value of the spherical muscle sphere at 60 GHz. The receiving power of the Doppler sensor can then be calculated from the radar equation at different frequency. From the theoretical upper bound value of the antenna gain (under the fixed antenna size), by observing the simulated receiving-power comparison, it is found that the Doppler sensor can receive more reflected power (from the spherical muscle sphere) for the higher carrier frequency (up to 60 GHz) which may have a better vital-signs sensing performance. Measured vital signs of a 60-GHz Doppler sensor system of a human subject 2-m away are also demonstrated.