1.Introduction
Antennas are key components of any wireless system. An antenna is a conductor that can transmit, send and receive Electromagnetic (microwave, radio or satellite) signals... Most antennas are resonant devices, which operate efficiently over a relative narrow frequency band. There are different types of antennas. The dipole antenna is the first type of antenna to be ever used and the simplest one to study and understand, it is a strait wire fed from the center. Directional antenna is used for antennas which radiates power in focused and specific direction. Microwave Antennas which include parabolic reflector and horn antennas and are used for high gain. The Microstrip patch antenna is a single layer design which commonly consists of four parts (ground plane, patch, the feeding part and substrate). Microstrip antennas, mostly referred to as patch antennas consists of a very thin metallic patch (usually copper or gold) placed a small fraction of a wavelength above a conducting ground plane, separated by a dielectric substrate. The radiating patch can be of any planar geometry e.g. circle, rectangle, square, elliptical, thin strip dipole, disc sector, triangular and circular ring. The radiating elements and the feed lines are usually etched on the dielectric substrate of a material.
Microstrip antennas have some advantages such as light weight, low cost etc and some disadvantages such as low bandwidth & efficiency. However there are different methods by which their efficiency and bandwidth can be improved. Microstrip patch antennas are low profile, conformable to planar and non planar surfaces, simple and inexpensive to manufacture using modern printed circuit technology, physically robust when mounted on rigid surfac...
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...ao, Antennas and Propagation for Body-centric Wireless Communications, Artech House, 2006.
6. DiBari, R., Q. H. Abbasi, A. Alomainy, and Y. Hao, An advanced UWB channel model for body-centric wireless networks," Progress In Electromagnetics Research, Vol. 136, 79{99, 2013.
7. Chahat, N., C. Leduc, M. Zhadobov, and R. Sauleau, Antennas and interaction with the body for body-centric wireless communications at millimeter-waves," 2013 7th European Conference on Antennas and Propagation (EuCAP), 772{775, 2013.
8. Liu, Z. G. and Y. X. Guo, Dual band low profile antenna for body centric-communications," IEEE Transactions on Antennas and Propagation, Vol. 61, No. 4, 2282{2285, 2013.
9. P. Salonen, Y. Rahmat-Samii, H. Hurme, and M. Kivikoski, "Dual-Band Wearable Textile Antenna", IEEE International Symposium on Antennas & Propagation, Monterey, CA, June 20 -26, 2004.
According to David Shriner, a former military engineer and expert on RF technology, there are a number of different types of RF weapons, which are also referred to as High Powered Microwave (HPM) weapons. The first type is the conventional RF weapon, which sends out a concentrated band of radio waves toward a target. These radio waves act in a way similar to the waves inside a normal microwave oven; given a sufficient amount of power, they can be used to heat and damage electronic equipment operating at the same frequency. Because of this need to match frequency with the target, conventional RF weapons require prior research and intelligence before they can be deployed effectively by terrorists [3].
Anticipate the moment at which all your personal electronic devices - headphone audio player, cellular telephone, pager, dictaphone, camcorder, personal digital assistant (PDA), electronic stylus, radiomodem, calculator, Loran positioning system, smart spectacles, VCR remote, data glove, electronic jogging shoes that count your steps and flash warning signals at oncoming cars, medical monitoring system, pacemaker (if you are so unfortunate), and anything else that you might habitually wear or occasionally carry - can seamlessly be linked in a wireless bodynet that allows them to function as an integrated system and connects them to the worldwide digital network. (Mitchell 29)
There was a time in our life when going wireless was a dream and was considered highly expensive but then started the era of WIFI. The first outcome of this wireless transmission was IEEE 802.11 standard for wireless data transmission and it progressed as a/b/n with the time. The last stand 802.11n was the real heavyweight and gained a lot of popularity based on its amazing performance. It gave almost 5 times increase in bandwidth using MIMO (Multiple Input Multiple Output) antenna technique. The user experience for 802.11n standard was so good that it was called “end of an Ethernet” at that time. AC standard operates in the 5GHz band with some enhanced physical layer set with the idea of better video communication. It comes with more antennas, wider channels and more spatial stream along with a number of new features to boost throughput and reliability. This new IEEE 802.11ac technology is in reality only an up gradation of physical layer wireless technique used in 802.11n by the use of multiple inputs multiple output (MIMO) antenna technique. Few improvements done in 802.11ac and modified parameters can be studied as following:
Sade, R. M. 2007. Radio frequency ID devices in humans. Report of the Council on Ethical and Judicial Affairs (CEJA) AMA. CEJA Report 5-A-07.
Miller, A.B. (2001), Bluetooth Revealed: The Insiders Guide to an Open Specification for Global Wireless Communications, 2nd Edition, USA, Prentice Hall [Accessed 6th April, 2008]
The idea of a wearing a watch for your wearable technology is I think the best spot on your body for one. There are so many different types of technological watches which do serve as a watch sometimes, but other times they have completely different uses. The Fitbit for instance, kind of stole Nike’s Nike+ idea of a shoe sensor connected to their Ipod, however like I said before a watch or wristband type technology is the most popular now a days for the simplicity of using it like a normal watch.
The microchip is used as the circuitry for the VeriChip and in it, a radio receiver and modulator as well as control logic and storage memory. The second component, the antenna and its made with a piece of coiled wire (Garfinkel, 2005). The VeriChip doesn’t require the use of batteries because it deprives all necessary electrical power to transmit its signal using the antenna which is coiled through physical property which is referred to as inductance. The VeriChip offers both passive and active RFID tags, the implantable, wearable and attachable. The implantable tag, this tag is inserted into the person and can be used for tracking, identification and medical uses. The wearable tag is worn by
For physically small antennas, the Wheeler cap method is highly preferred for measuring the radiation efficiency. According to this method, if a radiation shield is placed around the antenna so as to enclose the near fields of the antenna, the radiation resistance of the antenna is reduced to zero while the loss resistance and the stored energy remain the same as for the unshielded antenna. When covering the antenna with a metal cap, the radiation is suppressed and the input power (proportional to the input resistance) is equal to the power loss (proportional to the loss resistance). Without the cap, the input power is equal to the radiated power plus the power loss (input resistance + loss resistance). The radiation efficiency of the antenna can be obtained from these two parameters.
Microstrip patch antennas radiate primarily because of the fringing fields between the patch edge and the ground plane. For good antenna performance, a thick dielectric substrate having a low dielectric constant is desirable since this provides better efficiency, larger bandwidth and better radiation [4]. However, such a configuration leads to a larger antenna size.
"Microwaves, also known as Super High Frequency (SHF) signals, have wavelengths approximately in the range of 30 cm (1 GHz) to 1 mm (300 GHz)."
Targonski, S. D., R. B. Waterhouse, and D. M. Pozar, “Design of wide-band aperture-stacked patch microstrip antenna,” IEEE Trans. Antennas Propagat., Vol. 46, 1245–1251, Sep. 1998.
Wearable computing is the next step to the computer revolutionary world. At MIThril lab, they are working on a wearable computer. Like a sleeveless winter coat or a sweater, they are working toward they goal. With the complicated project, they don’t know the finishing line yet. But with every step the MIThril team takes, they freely document and post on the web for worldwide access. The name MIThril derives from the fictional classic The Hobbit and Lord of the Ring by J.R.R. Tolkien. As comfortable and unnoticeable as the Dwarves’ ring-mail tunic, MIThril’s team promises our gifted society the future clothes of electronic.
When antennas are placed close to human body, their performance is influenced by human body. Antennas that are near to the body have different resonance frequency than resonance frequency in free space. Changes in Resonance frequency, Impedance bandwidth, Gain, directivity and radiation pattern is observed when it is placed close to human body [2].
...rough overall body, in other words the extracellular fluids as well as intracellular fluid. The concept behind the multiple frequencies BIA method is taken the measurements a range of lower to high frequencies. From this it is possible to development of prediction equation from lower to high frequencies. By looking to the immense importance, success and popularity of Bioelectrical impedance Analysis Method, in our research work we have used this standard method. The buildup system evolved with taking features and advantage of complex multifrequency bioimpedance analysis method. This developed setup falls under such small size and low power embedded devices which can easily wearable access to the patient and capturing the real time data. With these the device has built in intelligence system and making control decision which help to patients with built in treatment.
To my mind after today’s standards - 3D and 4K- movies are going to come to a new level of entertainment. I am not talking about higher resolutions or better surround sound, but about blurring the line between the physical and the digital world. In other words, the move from watching a movie to being part of a movie. I might be wrong but who would not like to play his favorite character in a movie, interact with other characters and affect the movie’s outcome? Wireless bodysuits will make the audience feel, what their characters fee...