The work presented in this article aims to detect the cardiac movement of a person in a non-invasive way and to correlate it with a reference signal in the medical field: the electrocardiogram. To achieve this goal, a measurement campaign was carried out on twenty consenting individuals. On the one hand, the mechanical signal, the movement of the subject’s chest induced by the heartbeat, is recorded via a FMCW radar and on the other hand, the electrical signal of the heart is recorded via an ECG acquisition board. Signal processing functions and different filtering will allow the correlation of the radar and ECG signals. This study is conducted on apnea recordings in order to remove the impact of breathing on the movement of the chest. When the subject holds his or her breath, the two important phases of cardiac movement via radar capture can be detected: the systole and the diastole. The delay between the mechanical signal of the heart and the electrical signal of the heart, already explained by medicine, is well noted. The accuracy of motion detection provided by the radar allowed us to highlight the reproducibility of the chest movements detected during a capture. Their correlation with ECG data validates the proposed hypotheses.

This article introduces an innovative methodology for measuring the impedance of RFID (Radio Frequency Identification) chips. The primary objective is to develop a technique that enables impedance measurement across a range of frequencies, centered around the critical operational frequency of RFID systems, specifically 13.56 MHz. Unlike conventional methods, which typically focus solely on the impedance at 13.56 MHz, this approach utilizes the reflection coefficient of the device under test (DUT) to measure impedance over a broader frequency spectrum. This spectrum encompasses the frequencies within the ISO14443 communication bandwidth. The excitation signal is carefully selected to closely mimic an actual RFID communication frame. The experimental results demonstrate the feasibility of this method by comparing the impedance measurements of passive component pairs against those obtained using a vector network analyzer (VNA). Subsequently, the technique is applied to an RFID chip, underscoring its practical applicability and accuracy.

The deployment of embedded near-field communication (NFC) wearable devices continues to grow with the Internet of Things (IoT). Constraints on bill of materials (BOM) cost, representing all the components of a device, and available space lead manufacturers to seek alternatives to implement wireless charging. This article introduces an antenna solution to respond to requirements of NFC charging applications for smart ring form factors. The proposed study includes electrical parameter modelling, estimation of inductance, resistance, quality factor, and coupling coefficient together. This 3D helicoidal antenna operates in quasi-magnetostatic mode. The different pairs are then compared to existing representative planar reference antennas in simulation. The results are confirmed with experimental validation for the best case, worst case, and typical case. First, the article presents the different antennas produced. It defines the pairs of antennas and their respective coupling coefficients. The methodology to simulate and measure losses is also presented. Then, the article compares a representative planar reference with a prototype. The proposed methodology is validated through a comparison of simulations performed with identical S-parameters. This comparison demonstrates both the robustness of the model and the end-to-end charging performance of the prototype. Finally, the article presents a comparative simulation at 2 W and 3 W for all prototype pairs. All antennas provide improved end-to-end power transfer performance, achieving simulated efficiencies up to 64.2%, representing a maximum absolute improvement of 26.2 percentage points, with an average absolute improvement of 22 percentage points in the end-to-end efficiency compared to pre-existing representative planar reference antennas at the same operating power.

This article presents a novel triangular-shaped pulse design for Ultra-Wide-Band (UWB) radio pulses, specifically in compliance with the IEEE 802.15.4a standard and the Spectral Masks of the Federal Communications Commission (FCC). Utilizing a Genetic Algorithm (GA), our objective is to develop a triple pulse form that satisfies the requirements set by these standards. Theoretical analysis and simulations showcase enhanced performance in comparison to existing UWB pulses, achieving a power loss mask of 3%, off-band emission of 5% within an 8% emission band, and a remarkable spectral efficiency exceeding 75%.

The aim of this study is to examine the influence of the variation of the intrinsic impedance on the phase of a Gaussian pulse during propagation through a biological tissue. This paper describes a method for varying the intrinsic impedance while retaining the characteristics of the propagation medium. The propagation medium is considered as the superposition of four semi-infinite layers each characterized by their thickness, their conductivity, and their dielectric constant. These last parameters, on which the intrinsic impedance depends, are functions of the pulsation of the medium. In this work, we will test the continuity of the phase shift of the signal at the level of interfaces of biological layers with respect to that of the starting point as the function of the excitation pulsation. Next, we are going to vary the intrinsic. Next, we examine the influence of the variation of the intrinsic impedance at the interface on the phase shift of the signal at that level. We will adopt the Finite Difference Time Domain (FDTD) method to simulate the propagation of a Gaussian pulse. This method which is validated in previous work showed robustness to obtained signals very close to the reality at the interfaces. For these two tests, we will notice that the variation of intrinsic impedance has no influence on the variation of the phase at the interfaces.