This work presents a single-antenna self-injection-locked (SIL) radar to reduce the hardware complexity of continuous-wave (CW) Doppler systems. The theory provides a basis for determining the signal-to-noise spectral density ratio (SNDR) with the effects of clutter. Experimental results agree closely with the theoretical predictions, showing that the clutter does not affect the optimal SNR performance in an SIL radar. A single-antenna SIL radar array is designed to detect vital signs with random body movement cancellation. To this end, a subject is placed between two single-antenna SIL radars to measure the rates of respiration and heartbeat using Doppler shift, and the effects of random movement of the subject are cancelled by wireless mutual injection locking (MIL) of the two radars. In an experiment, a prototype of such a two-radar array with a spacing of 2 m was implemented at 2.4 GHz, providing accurate and reliable cardiopulmonary monitoring of a subject who jogged on a treadmill with random body motion of many centimeters.

Abstract-This paper presents a self-injection-locked (SIL) radar with ranging and tracking capabilities to see through walls for discovering hidden people. Characterized by low complexity and high sensitivity, the proposed SIL radar merges the frequency-modulated continuous-wave and sum-difference pattern detection approaches to determine the distance and azimuth from the radar to each individual in a scene behind a wooden partition wall. An individual can be distinguished from a stationary object by using dynamic spectral subtraction to extract human motions or vital signs. Additionally, two or more individuals can be distinguished from each other by decomposing the Doppler signal into contributions of individuals in a polar domain. Consequently, a see-through-wall imaging system is constructed with the proposed SIL radar to position different individuals concealed behind a wall.

Abstract-A novel vital-sign sensor with a self-injection-locked oscillator and a frequency demodulator to reduce system complexity and improve sensitivity is proposed. The theory provides a delta-sigma model to account for the excellent signal-to-noise spectral density ratio in a parametric study of the sensitivity performance. Then, the experiments verify the sensing principle and the predicted performance. Accordingly, a prototype sensor with high sensitivity is realized for noncontact cardiopulmonary monitoring, achieving a long sensing distance without the need for a low-noise amplifier. The sensing distance can grow four times longer by doubling the operating frequency. Furthermore, the sensor using a swept frequency can eliminate the null detection points and the external radio interference. As an experimental result, the sensor, which is placed 4 m away from the subject, can reliably detect the heartbeat signal an the operating frequency of 3.6 GHz and an output power level of 0 dBm. Index Terms-Delta-sigma model, frequency demodulator, selfinjection-locked oscillator, vital-sign sensor.

Abstract-This paper formulates various quality ( ) factors associated with the applications of on-chip spiral inductors to radiofrequency integrated circuits using -parameters. The formulations start with the factor of a spiral inductor in a generalized two-port configuration based on a new complex-power approach and then extend to the factors of a tank and matching circuits that use the spiral inductors. In the demonstration, the two-port -parameters for a series of CMOS spiral inductors have been measured to further generate such various factors for a manysided evaluation of the inductor performance.Index Terms-Complex power, on-chip inductor, quality ( ) factor, -parameters, spiral inductor.

No abstract