Ultrathin perfect absorber based on integrated metamaterial

We improved common metamaterial perfect absorber (MPA) by integrating four embedded inductors or replacing four embedded capacitors in the same compact structure. The obtained results confirmed that the lumped-capacitors MPA maintains an extreme thickness t = λ/940, where λ is operating wavelength at 106.3 MHz. Besides, by replacing these capacitors by inductors in the initial designed-MPA structure, we obtained an effective thickness of t = λ/53 at 1.9 GHz. Furthermore, we explained the absorption mechanism in terms of the magnetic energy and power loss distributions related to the impedance-matching effect.

Thermal stability analysis of passive components embedded into printed circuit boards

Purpose The purpose of this paper is to investigate the behavior of embedded passives under changing temperature conditions. Influence of different temperature changes on the basic properties of embedded passives was analyzed. The main reason for these investigations was to determine functionality of passives for space application. Design/methodology/approach The investigations were based on the thin-film resistors made of Ni-P alloy, thick-film resistors made of carbon or carbon-silver inks, embedded capacitors made of FaradFlex materials and embedded inductor made in various configurations. Prepared samples were examined under the influence of a constant elevated temperature (100, 130 or 160°C) in a long period of time (minimum of 30 h), thermal cycles (from −40 to +85°C) or thermal shocks (from −40 to +105°C or from −40 to +125°C). Findings The achieved results revealed that resistance drift became bigger when the samples were treated at a higher constant temperature. At the same time, no significant difference in change in electrical properties for 50 and 100 Ω resistors was noticed. For all the tests, resistance change was below 2 per cent regardless of a value of the tested resistors. Conducted thermal shock studies indicate that thin-film resistors, coils and some thick-film resistors are characterized by minor variations in basic parameters. Some of the inks may show considerable resistance variations with temperature changes. Significant changes were also exhibited by embedded capacitors. Originality/value The knowledge about the behavior of the operating parameters of embedded components considering environmental conditions allow for development of more complex systems with integrated printed circuit boards.

Dielectric Response and Transport Properties of Pb2Sr2CaCu2O9 [Lead Strontium Calcium Copper Oxide]

High dielectric permittivity, good mechanical properties and excellent thermal stability are highly desired qualities for the dielectric materials used in embedded capacitors and energy-storage devices. This study reports the temperature dependence and very low loss factor of Pb2Sr2CaCu2O9 ceramics. X-ray diffraction (XRD) and scanning electron microscope (SEM) are used to analyze the sample. The dielectric properties of the material prepared has been investigated in the frequency range 42–1[Formula: see text]MHz and in the temperature range 303–873[Formula: see text]K. The result reveals that Pb2Sr2CaCu2O9 have high dielectric constant with significant temperature and frequency dependence which makes them appropriate in the application of miniaturization of electronic devices. The dielectric constant and the loss factor decreases with increase in frequency of the applied field. Impedance studies confirm that dielectric relaxation in the material is of non-Debye type. Conductivity studies proves quality information related to the charge transport properties. The frequency analysis of modulus properties pictures a distribution of the relaxation time existing in the system. The new ceramic material Pb2Sr2CaCu2O9 will be a promising candidate for uses in embedded capacitors, especially in high-temperature circumstance.

Assessment of stability and reliability of embedded components in printed circuit boards

Purpose The purpose of this paper is to investigate the basic functional parameters of passive embedded components in printed circuit boards (PCBs) under environmental exposures such as thermal-humidity and thermal exposure. Design/methodology/approach The investigations were based on the thin-film resistors made of NiP alloy, thick-film resistors made of carbon or carbon–silver inks, embedded capacitors made of FaradFlex materials and embedded inductor made in various configurations. The capacitors and thin- and thick-film resistors were tested in the climatic chamber in conditions of thermal-humidity exposure at 85°C and 85 per cent RH for 500 h. The embedded inductors were tested in two different environmental conditions: thermal-humidity exposure at 60°C and 95 per cent RH, and thermal exposure at 150°C and additionally at the temperature in the range of +25°C to +150°C. Findings Studies show that in the case of embedded capacitors, the changes caused by exposure to thermal-humidity are durable and lead to the capacity increase. The embedded thin-film resistors behave in the same manner, whereas the thick-film resistors were the least resistant to the conditions of exposure. Most of the polymer thick-film resistors have been damaged. The changes of coils' properties during aging are small, and what is most important is that, after some time of exposure, their parameters stabilize at a particular level. The changes resulting from the increase in temperature are typically related to the change of material resistance (Cu) of which coils are made, and as such, they cannot be avoided but they can be predicted. Research limitations/implications The realized studies allowed determination of the properties of the embedded passive elements with respect to specific environmental exposures. The studies show that embedded resistors can be used interchangeably with chip passive elements. It allows saving the area on the surface of PCB, occupied by these passive elements, for assembly of active elements integrated circuits (ICs) and thus enabling the miniaturization of electronic devices. Originality/value The knowledge about the behavior of the operating parameters of embedded components, considering the environmental conditions, allows for development of more complex systems with integrated PCBs.