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Ceramics is a term that has a wide range of meanings, from eggshell-delicate Denby vases to equally delicate chips packed with circuitry. But in this context, the focus is on transition-metal oxide-based ceramics and their importance to modern electronics, especially within cellular phones.
Ceramics have an array of properties that make them incredibly useful within the electronics industry. These include insulation, dielectric property, pyroelectric property, piezoelectricity, superconductivity, magnetic properties, and their biggest selling feature, the one without which current technology as we know it would be impossible - semiconductivity. As a result, they are used to manufacture an amazing breadth of electronic components with single functions, such as filters, resonators, and sensors, capacitors, as well as those with multiple functions, including wireless modules that have a special type of ceramic called LTCC or low-temperature co-fired ceramic as the material, in most cases outperforming the older materials.
Miniaturization and Ceramics
Another factor that played a major role in bringing electronic ceramic components to the fore is size reduction. The need for thinner and smaller consumer electronics made the ability to miniaturize ceramics components a significant advantage and led to the current trend of downsizing electronics.
Apart from the inherent functionality and small-size capability, ceramics also have a much smaller ecological footprint than other comparable materials like tantalum.
Ceramics are present almost everywhere in modern cell phones. For example, the cell phone antenna is necessary for signal reception and voice transmission. The antenna of most phones is made of ceramic material. Ceramic antennas are also used for Bluetooth and GPS systems.
Every smartphone contains a System on a Chip, or SoC. A SoC contains almost all of the phone’s brains: the microcontroller, the graphics processor, the WiFi card, and the Random Access Memory. And none of this would be possible without ceramics. Each of these components contains anywhere between ten and several millions of components. Other ceramic components in modern smartphones include an array of almost 250 capacitors, as well as four dozen chip inductors and electromagnetic interference (EMI) suppression filters.
One of the most important and basic of these is the capacitor. Capacitors are small electric devices that store charge and release it when required. A SoC contains billions of capacitors: if traditional capacitors were used, a typical processor would be as bigger than a house - and they were, back in the 1900s when computers were still being developed. But once ceramic capacitors were created, there was no looking back. These are capacitors that use ceramic materials in sub-micron sized particles to enhance charge retention. New manufacturing techniques allow for the creation of incredibly thin dielectric layers - thinner than one-tenth of a micrometer. These developments led to the creation of capacitors that are small enough to be used in cell phones, yet powerful enough to run advanced computing tasks.
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Again, battery life is a crucial performance point for any mobile device. In this area too, ceramics are essential, as they are in managing energy, being used in smart-grid products which are meant to conserve energy and result in lowering the cost of the energy used.
Another useful property of ceramics is piezoelectricity. This means that if an electric field is applied across a certain type of ceramic, it will oscillate at a fixed frequency. This property of ceramics is used to insert a timing property in the computer systems of cell phones.
Because of ceramic’s insulative properties, resistors are composed of metal film placed on a ceramic base. Ceramics are very hard, and can be extremely insulative. Computer components are often coated with ceramic to protect them. Ceramic is used in the protective outer covering of sensitive integrated circuit chips due to their thermal stability, hardness, and low cost. Ceramics are also used to create heat sinks to keep the processor’s temperature at safe levels.
Dielectric resonators (DR) are electromagnetic components that show a useful range of resonance over limited frequencies. Usually comprising a ceramic puck with high permittivity, and low dissipation, its resonance properties are dependent upon the physical size and permittivity of the resonator. A high quality factor, high relative permittivity and temperature coefficient near zero define an ideal DR. However, ceramic DRs come close to fulfilling these requirements, enabling miniaturization and a higher quality factor. Some ceramics used for this purpose include BaTi4O9, (BZT) or Ba[Zn/3Ta2/3]O3, and (BMT) or Ba[Mg/3Ta2/3]O3, among others, and these are often called the “talking ceramics”. They are crucial in GPS and other wireless microwave-based communications technology.
Ceramics are thus essential to all cell phones and are present in almost every aspect of its technology.
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