A Method For Efficiency Enhancement And Size Miniaturization

During the iPhone 4 development process, testing was theoretically performed in-house to identify any potential technical glitches in design, performance or overall functionality of the device. Apple has spent millions of dollars in antenna design and test labs. These advanced facilities are exclusively used to measure the antenna and wireless performance, featuring seventeen different antenna anechoic chambers that record antenna strength. Apple engineers logged thousands of hours performing various signal tests throughout the two year development period. Lab tests lead to eventual field testing which has been documented to be done under various conditions simulating realistic conditions. Apple had ample time to discover any antenna signal loss deficiencies in the iPhone 4 design and speculation has begun to brew as to how this issue failed to be identified long ago.

Here first we design a simple rectangular shaped microstrip patch antenna with dimension 14 X 14 X 1.60 mm^3 shown in Fig.1. In this antenna the dimension of patch is 10 X 13 mm^2. We are using microstrip line feed to this rectangular patch with length 4mm and width 1.6mm. By simulating this simple patch antenna we were getting only two frequency bands as shown in Fig2.

In the underlay approach, secondary users should operate below the noise floor of primary users, and thus severe constraints are imposed on their transmission power. Ultra-wideband (UWB) technology is very suitable as the enabling technology for this approach. In spectrum overlay CR, secondary users search for unused frequency bands, called white spaces, and use them for communication.

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Window embedded wire antennas have been introduced at FM frequencies for low-power or receive-only applications. The power transmitted by the army radios at VHF and UHF frequencies can exceed tens of watts. At these power levels, it is of crucial importance to isolate the interior of the vehicle from the antenna radiation. In addition, this isolation eliminates the affects of the cabin interior and passengers on the antenna input impedance and radiation pattern. Hence a transparent ground plane will be needed behind the radiating element to reduce the radiation inside the vehicle and at the same time increase the directivity of the antenna. A wire-mesh or a more sophisticated band-selective ground plane can be used as the reflecting element. A meshed patch antenna on a mesh ground plane can provide the required isolation with the cabin interior. However because of the sub-wavelength dimensions of the armored windows at VHF and UHF frequencies a patch antenna, if feasible, cannot provide the one octave bandwidth required by the army radios. In this paper a monopole bow-tie antenna backed by a cavity (armored window) is proposed. Because of the limited thickness of the window glass, the radiation element and the transparent ground plane need to be placed very close to each other. Therefore the gain and/or the

The equation for radiation resistance is given in (1). As can be seen, the greater the radiation resistance, the more energy is radiated or received by the antenna. When the radiation resistance of the antenna matches the resistance of the transmitter or receiver, the system is optimized. Antennas also have ohmic or loss resistance which decreases efficiency. It can be shown that an efficient antenna must be comparable to a wavelength in size.

The fig.3 and 4 above is a simulated result showing the red is return loss (S11) and blue is insertion loss (S21) obtained for model. Figure 4 shows the reflection and transmission factor measured for the range 1 GHz to 4GHz. This result gives that the bandpass characteristics are valid for a wide range of EM spectrum for communication. In order to get detailed characteristics in the neighborhood of 2.45 GHz, Figure 4 gives more information needed to the measurement results. With the 3 dB boundary, we get about 260 MHz bandwidth, and insertion loss of -4.3 dB, with parametric dimension as given in Table.1.

25. Which version of 802.11 technologies can use two antennas at both the access point and the network adapter? 802.11n

Taking this background, I intend to move forward and expand my existing base of expertise and dive head first in to the realm of wireless! In my last several roles, wireless connectivity has been the bleeding edge of both end user desires as well as security concerns. I have a keen interest particularly in distributed antenna systems or DAS. While most common with cellular network, they are making end roads in the enterprise and commercial WiFi arena. It is estimated that roughly 5% of commercial WiFi implementations use disturbed antenna systems. Given my background as a security professional, I not only see the benefits of indoor and outdoor distributed antenna systems. Not only from the power consumption perspective, but also from both the size and most importantly the ability to “right size/shape” the coverage area. This is especially true in multi-use office buildings and where terrain may be an obstacle.

Over the years, windows have evolved with a new technological advancement, known as high efficiency windows. The introduction of these windows has allowed people to dramatic cut their energy consumption and includes many other advantages. If you are tired of having a poorly insulated house, installing high efficiency windows in your house could help improve this problem. Many homes today do not include these types of windows, so people end up paying more for their heating and cooling systems/bills. Installing these windows into your home can make a big difference in your house and in this essay I will explain why.

In this paper of Wireless USB, I will try to give the uses of WUSB, its advantages, work area, features of using WUSB, etc. At the same time I will points out the application of using WUSB along with its specification.

Research data shows that if the path loss is less than 160dB, the outage probability for both 36 m height transmitter and 18 m height transmitter is 0% within 200m. This outage study also indicates that within 200 m from the transmitter, a lower transmitter experienced fewer outages since it is able to use more reflectors in the environment to cover all locations. However, a higher transmitter can get smaller outage probability because of the diffraction of signals around lower buildings if the distance is over 200 m [32]. This work

We have Review different research paper. Accordingly it is used to achieve significant bandwidth enhancement and analyze the matching and radiation properties of sub wavelength resonant patch antenna filled with double-negative, double positive and single negative meta material block ,quasi static equivalent circuit model for analysis and design of different types of artificial magnetic resonator and the possibility of using an active internal matching element in several type of metamaterial inspired electrically small antenna to overcome their

Nanofluids are another sort of warmth exchange medium, containing nanoparticles (1–100 nm), which are consistently and steadily distributed in a base liquid (Wang & Mujumdar, 2007). Down scaling or scaling down has been a late major pattern in cutting edge science and innovation. Builds now manufacture miniaturized scale gadgets, for example, micro channel heat exchangers, and small-scale pumps that are the measure of dust bits. Further significant advances would be gotten if the coolant streaming in the smaller scale channels were to contain nanoscale particles to upgrade heat exchange. Nanofluids innovation will in this way be a rising and energizing innovation of the 21st century. This paper gives explanation on the nanofluids technology and its performance advantages. It likewise depicts case of potential applications and characterizations of nanofluids. At long last, future examination on the fundamentals and utilizations of nanofluids are great (Wang & Mujumdar, 2007).

Abstract – In this letter, we describes the planning and comparative analysis of circular patch with FSS layer with regard to dimensional characterization. Patch and substrate can play the important role within the performance of the antenna. Dimensions and material of the substrate has an influence on the output parameters of the antenna. A comparative analysis is finished for the 2 models and Simulation output parameters return loss, VSWR, gain, radiation patterns and field distributions for each the cases square measure bestowed during this work. Substrate utilized Roger RT/Duroid 5880(TM) which has a dielectric constant of 2.2. The result demonstrates the wideband radio wire (antenna) to work exactly from 5.8GHz frequency band with ideal resonant frequency at 5.8GHz. This antenna mainly designed for wireless application as WLAN, Bluetooth and etc.