A novel multiband frequency-reconfigurable antenna is presented. The designed antenna can realize L-band single-frequency operation and S-band dual-frequency operation through electronic tuning. Annular ring and sawtooth patches are used as radiators for L/S-band operation and are excited by a broadband reconfigurable orthogonal network through the coupling of a T-shaped slot and a ring slot in the ground plane, respectively. By changing the bias of the p-i-n diodes loaded on the feed network, the operating frequency can be switched between the navigation state and the satellite link receiving state. A high tuning frequency ratio (1.64:1) is obtained. The simulated and measured results show good agreement. Good impedance matching (VSWR < 1.3) and circular polarization characteristics (AR < 3) are obtained in all three operating bands. Achievement of a highly reconfigurable frequency ratio of a circularly polarized antenna provides solutions for multifunction CP antenna aperture sharing.

Inaccurate measurements of analog sensors caused by electromagnetic interference (EMI) signals threaten the security and reliability of sensor-based systems. This article proposes a self-check method for recognizing and correcting disturbed measurements of analog sensors under EMI signals. The core basis of this method involves the use of a dummy sensing element to make the sensor sensitive only to EMI signals, rather than the measurand. This configuration enables the sensor to switch between normal mode and self-check mode through switching devices. Then the sensor response to EMI signals in normal mode is characterized by that in self-check mode, which is computable. A detailed implementation framework is derived to ensure that the sensor responses to EMI signals in both modes are highly similar, involving the properties of the dummy sensing element, the input voltage of the operational amplifier (opamp), and the power supply rails. Owing to its low demand for additional components and computing resources, the proposed self-check method is cost-effective and convenient to implement. Its effectiveness and robustness are validated on a temperature sensor, an ambient light sensor, a linear variable differential transformer (LVDT) and a wireless temperature sensor node with EMI experiments using different signals parameters, temperatures and light intensities. The experimental results show that this method can enhance the measurement accuracy of analog sensors to help maintain the functioning of sensor-based systems under EMI signals.

An electronic system generates a large number of intended or unintended electromagnetic radiated emissions in its operating state, which can lead to potential electromagnetic compatibility (EMC) problems. To avoid the impact of these electromagnetic radiation emissions on the surrounding electronic equipment or systems, it is necessary to classify and identify these radiation emitters. In this paper, we proposed a systematic approach for radiation emitter classification and identification based on radiation emission components. Inspired by the basic emission waveform theory (BEWT), the radiation emission data of electronic systems are decomposed into three kinds of radiation emission components, and the different groups of radiation emission data can be classified or identified according to the similarity of these radiation emission components. The radiation emission (RE) spectral data of several kinds of electronic equipment, such as laptops and digital cameras, were used to verify the proposed method. The classification and identification accuracy for data corresponding to different kinds of radiation emission spectra was about 99%, which confirmed the effectiveness of this method.

Since many third parties involved in integrated circuit (IC) manufacturing, hardware Trojans malicious implantation have become a threat to the IC industry. Therefore, varieties of reliable hardware Trojan detection methods are needed. Since electromagnetic radiation is an inherent phenomenon of electronic devices, there are significant differences in the electromagnetic radiated characteristics for circuits with different structures and operating states. In this paper, a novel hardware Trojan detection method is proposed, which considers the electromagnetic radiation differences caused by hardware Trojan implantation. Experiments of detecting hardware Trojan in field programmable gate arrays show that the proposed method can effectively distinguish the ICs with Trojan from the ones without Trojan by the radiated emission.

This article develops a semianalytical model for characterizing the terminal responses of coated floating-ground multiconductor cables (FMCs) with arbitrarily routed wiring structures illuminated by a nonuniform electromagnetic field. In contrast to previous transmission line (TL) models, where only differential-mode (DM) coupling was considered, the proposed method decomposes the field-to-wire coupling effects in coated FMCs into common-mode (CM) coupling and DM coupling. First, for CM coupling, the coated FMCs are equivalent to a CM single conductor, and the CM current distribution along this conductor is obtained by full-wave simulations. Second, the equivalent coupled sources are decomposed into CM sources converted from the CM currents and DM sources induced by the electric and magnetic fields. The CM and DM sources are obtained separately by discretizing coated FMCs and sampling the incident electromagnetic field. Third, the combination model accounting for the comprehensive DM coupling is derived utilizing TL theory based on the equivalent coupled sources. The proposed method is validated through two application examples with good accuracy and higher computational efficiency compared with full-wave simulations.