In order to operate in the fundamental 10 TM mode, the length of the patch must be slightly less than λ / 2 where λ is the wavelength in the dielectric medium and is equal to λ0 / ε ff where λ is the free space wavelength. The 10 TM modes implies that the field varies one
Romanenko et al. identified a correlation between large LAM values and the “hot” regions of cavities [10, 11]. The temperature increase from local heating increases the fraction of normally conducting electrons, so any potential sources for the heating need to be minimized. A proposed explanation for the local heating is that dislocations vibrate with passing phonons and disperse them, thus slow down thermal conduction . Dislocations can also affect cavity performance if they pin magnetic flux centers, resulting in irreversibility of magnetization curves . These adverse effects of dislocations necessitate a heat treatment for recovery or recrystallization after deep drawing.
They have good mechanical strength, and are hard, chemically inert and immune to humidity, which lead to the application of piezoelectric ceramics for the generation of voltage, electromechanical actuation, frequency control and the generation and detection of acoustic and ultrasonic energy [1, 3]. Piezoelectric ceramics are used in generators, sensors, actuators, and transducers, etc. . They are also used in daily life such as some piezoelectric cigarette lighters, most battery operated smoke detector alarms, many gas grill igniters . There have been a variety of research due to the wide applications of piezoelectric ceramics and the prospect for future development and improvement. Therefore, this paper will briefly introduce the history, applications and future development of piezoelectric ceramic
These to scientists used their knowledge of crystal structures and behavior they first described the piezoelectric effect. For this purpose they used many crystals such as quartz, cane sugar, topaz , tourmaline, and Rochelle salt. As per their analysis Quartz and Rochelle salts shown the piezoelectric effect at the time.
The synthesis of semiconductor devices in microelectronics and photonics applications has always fascinated me, and the field of developing electronic and photonic solid-state devices is a field that I find continuously interesting and rewarding. The physics behind these devices and their manufacturing are consistently setting new limits or allowing for new methods that produce useful applications. By embracing and driving research, industries which rely on evolving electronic devices and methods enjoy a rapid pace of development. Because of this, we see photonic solutions proposed as an alternative to the more physical electronic devices. Moreover, we see approaches that integrate these worlds.
Ultra high temperature ceramics (UHTCs) are materials rarely found in nature, characterized by high melting points, hardness, thermal conductivities (if compared to other ceramics), good wear resistance and mechanical strength.1,2,3 Besides, they are chemically and thermally stable under a variety of conditions due to their high negative free energy of formation.1,3
In order to solve the influence of electromagnetic interference to electronic devices may have extreme effects on each other if proper shielding protection is not appropriately put into use. The materials are more and more used to give to structure lightening in electromagnetic shielding applications. The interactions between electromagnetic waves and materials are highly dependent on tiny design. This gives rise to put modeling issues. The work of research will be more oriented towards the modeling of the electromagnetic behaviors of the structures implemented and of the materials with respect to the followed temperature variations. The electromagnetic shielding effectiveness (SE) calculate the electromagnetic guidelines was increased
Highly porous ceramics (foams, honeycombs, fibres , mats, etc.) find numerous applications in various engineering fields, including filtration (molten metals, particulate from diesel exhaust gases), radiant burners, catalyst supports, biomedical devices, kiln furniture, reinforcement for metal matrix composites, bioreactors, thermal protection systems, supports for space mirrors, components in solid oxide fuel cells, lightweight sandwich structures, heat exchangers (graphite foams), etc.
NiCuZn ferrites are excellent soft magnetic materials in high frequency device due to their low cost, high resistivity and low eddy current losses that have been extensively studied for multi layer chip inductor (MLCI) applications . NiCuZn Ferrite materials are widely used in various
Conventional passive RFID tags contain no internal power source, but instead harvest power from the RF signal transmitted by the RFID reader system. RFID readers provide sufficient power in the transmitted RF carrier signal to energize the tag circuitry through the coupled tag antenna. For a high frequency RFID system, for example, the wavelength of the 13.56-MHz carrier is 22.12 m. The typical parallel resonant circuit of a tag antenna comprises the inductance, resistance, and capacitance of the antenna loop (see Fig. 5) with resonant frequency. Frequency = ଵ ଶπ√ሺ L_ଶ∗Cሻ
The patch antenna plays a very important role in today’s world of wireless communication systems .There is always a large demand for high performance ,small size and low cost wireless communication systems .in order to get these requirements ,planar patch antenna is preferred because of their various advantages such as light weight ,low volume ,low cost and ease for fabrication .although the microstrip patch antenna has various advantages it has various disadvantages which are low gain ,narrow bandwidth and low efficiency .These disadvantages can be overcome by constructing many patch antennas in array configuration. Recently there has been increasing demand in the use of DGSs for performance enhancement of microstrip patch antennas and planar array antennas .there are basically two types of structures which are used for the design of compact and high performance wireless communication systems named as defected ground structures (DGS) and electromagnetic band-gap structures (EBG) which is also known as photonic band-gap structure(PBG). These structures have been used to obtain the functions such as unwanted frequency rejection and circuit size reduction. Recently defected ground structures have been introduced; DGSs are realized by simply etching off simple shape (called as defect) from the ground plane .Depending upon the shape and the dimensions of the defects ,the current distribution in the ground plane is disturbed and resulting in a controlled
ANDREA ALU et alThe outer dielectric slab and ground plane were supposed to be finite with circular symmetry and outer radius a=30mm.For a realistic implementation of inner code with an MNG material,again a drude model has been assumed with µ2(w)=µ0(1-wmp^2/[w(w-jwt)]and thickness of substrate has been increased to h=5mm with respect to previous design in order to allow more spacing for future hosting the split ring resonators to construct an MNG
Gathering ambient energy from radio frequency is called RF Energy harvesting [1-2]. This includes designing of antenna and some additional circuit that convert EMF radiation into DC voltage so that it can be used to drive low power devices. The concept of wireless power transmission is the basic principle behind RF Energy radiation in free space. The wireless transmission includes Bluetooth, GPS, Satellite communication, Wi-Fi, DTV. The wireless technology reduces cost of installation by eliminating wired transmission thus it is easy for us to carry wireless