Small, light weight and multifunctional electronic components are attracting much attention because of the rapid growth of the wireless communication systems and microwave products in the consumer electronic market. The component manufacturers are thus forced to search for new advanced integration, packaging and interconnection technologies. One solution is the low temperature cofired ceramic (LTCC) technology enabling fabrication of three-dimensional ceramic modules with low dielectric loss and embedded silver electrodes. During the past 15 years, a large number of new dielectric LTCCs for high frequency applications have been developed. About 1000 papers were published and y500 patents were filed in the area of LTCC and related technologies. However, the data of these several very useful materials are scattered. The main purpose of this review is to bring the data and science of these materials together, which will be of immense help to researchers and technologists all over the world. The commercially available LTCCs, low loss glass phases and researched novel materials are listed with properties and references. Additionally, their high frequency and thermal performances are compared with the other substrate material options such as high sintering temperature ceramics and polymers, and further improvements in materials' development required are discussed.

Jet stream: Multi‐walled carbon nanotubes grown by catalytic chemical vapor deposition were carboxylated in a two‐step oxidation process. An aqueous dispersion of the functionalized nanotubes was dispensed using an inkjet printer to obtain electrically conductive patterns on paper and plastic surfaces (see picture). Sheet resistivities for the deposited patterns of about 40 kΩ/□ could be achieved by multiple prints.

In addition to the constant demand of low-loss dielectric materials for wireless telecommunication, the recent progress in the Internet of Things (IoT), the Tactile Internet (fifth generation wireless systems), the Industrial Internet, satellite broadcasting and intelligent transport systems (ITS) has put more pressure on their development with modern component fabrication techniques. Oxide ceramics are critical for these applications, and a full understanding of their crystal chemistry is fundamental for future development. Properties of microwave ceramics depend on several parameters including their composition, the purity of starting materials, processing conditions and their ultimate densification/porosity. In this review the data for all reported low-loss microwave dielectric ceramic materials are collected and tabulated. The table of these materials gives the relative permittivity, quality factor, temperature variation of the resonant frequency, crystal structure, sintering temperature, measurement frequency and references. In addition, the methods commonly employed for measuring the microwave dielectric properties, important from the applications point of view, factors affecting the dielectric loss, methods to tailor the dielectric properties and materials for future applications, are briefly described. The data will be very useful for scientists, industrialists, engineers and students working on current and emerging applications of wireless communications.

Energy harvesting technology may be considered an ultimate solution to replace batteries and provide a long-term power supply for wireless sensor networks. Looking back into its research history, individual energy harvesters for the conversion of single energy sources into electricity are developed first, followed by hybrid counterparts designed for use with multiple energy sources. Very recently, the concept of a truly multisource energy harvester built from only a single piece of material as the energy conversion component is proposed. This review, from the aspect of materials and device configurations, explains in detail a wide scope to give an overview of energy harvesting research. It covers single-source devices including solar, thermal, kinetic and other types of energy harvesters, hybrid energy harvesting configurations for both single and multiple energy sources and single material, and multisource energy harvesters. It also includes the energy conversion principles of photovoltaic, electromagnetic, piezoelectric, triboelectric, electrostatic, electrostrictive, thermoelectric, pyroelectric, magnetostrictive, and dielectric devices. This is one of the most comprehensive reviews conducted to date, focusing on the entire energy harvesting research scene and providing a guide to seeking deeper and more specific research references and resources from every corner of the scientific community.

An ABO3-type perovskite solid-solution, (K0.5Na0.5)NbO3 (KNN) doped with 2 mol.% Ba(Ni0.5Nb0.5)O3-δ (BNNO) is reported in this communication. Such a composition yields a much narrower bandgap (~1.6 eV) compared to the parental composition -pure KNN -and other widely used piezoelectric and pyroelectric materials (e.g. Pb(Zr,Ti)O3, BaTiO3).Meanwhile, it exhibits the same large piezoelectric coefficient as that of KNN (~100 pC N -1 ) and a much larger pyroelectric coefficient (~130 µC m -2 K -1 ) compared to the previously reported narrow bandgap material (KNbO3)1-x-BNNOx. The unique combination of these excellent ferroelectric and optical properties opens the door to the development of multi-source energy harvesting or multi-functional sensing devices for the simultaneous and efficient conversion of solar, thermal and kinetic energies into electricity simultaneously and efficiently in a single material. Individual and comprehensive characterizations of the optical, ferroelectric, piezoelectric, pyroelectric and photovoltaic properties are investigated with single and co-existing energy sources. No degrading interaction between ferroelectric and photovoltaic behaviors was observed. This composition may fundamentally change the working principles of state of the art hybrid energy harvesters and sensors, and thus significantly increase the unit 2 volume energy conversion efficiency and reliability of energy harvesters in ambient environments.Various energy harvesting (EH) techniques have been investigated in recent decades in order to overcome the shortcomings of batteries in terms of lifespan, overall cost-effectiveness and chemical safety. [1] However, the power level and stability provided by a single-source energy harvester are often insufficient for practical applications. In order to address this issue, various hybrid energy harvesters have been developed and investigated. [2][3][4] However, as such hybrid energy harvesters have mostly been simple physical combinations of individual harvesters made from different materials/structures, the effective size of the entire system can become much larger than its individual counterparts. [2,3] In such a case one has to compromise either on the number of simultaneously harvested energy sources or on the space taken by different energy harvesting components. [5] This compromise usually leads to the loss of the advantage of energy harvesters over batteries. A similar situation may occur in hybrid sensors.One method to solve the problem is to design or discover a single composition/material which enables the simultaneous harvesting/detection of multiple energy sources. At the same time the individual conversion efficiency of the material for each energy source should be neither reduced nor interrupted in this multi-task performance. This requires different energy conversion effects exhibited by the same material to be independent of each other, or coupled but working in the same direction, and to be functional simultaneously. This communication reports a perovski...

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Composite technology, where a novel artificial material is fabricated by combining, for example, ceramic and polymer materials in an ordered manner or just by mixing, was earlier used widely for sonar, medical diagnostics, and NDT purposes. However, in recent decades, large numbers of ceramic-polymer composites have been introduced for telecommunication and microelectronic applications. For these purposes, composites of 0-3 connectivity (a three-dimensionally connected polymer phase is loaded with isolated ceramic particles) are the most attractive from the application point of view. Composites of 0-3 connectivity enable flexible forms and very different shapes with very inexpensive fabrication methods including simply mixing and molding. In this brief review, we gather together the research carried out within 0-3 ceramic-polymer composites for microwave substrates, also including embedded capacitor, inductor, or microwave-absorbing performances.

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