Advantages And Disadvantages Of Using Metmaterials

The horizontal resolution worsens as the reflectors are separated from the frequency because the footprint gets larger. The simulation and experimental values range approximately from λ/2 to 2λ for the high frequency. The results obtained for different frequency, the wavelengths converge when the bars are buried far from the antennas. In the horizontal resolution, the influence of the reflector's material is smaller. The best resolution is obtained with the 1 GHz as its resolution is slightly better than for the 800

Here we cut a cylindrical slot in the patch with outer radius R1 and inner radius R2 (R1>R2) as shown in Fig.5. By using cylindrical slot in the above rectangular slot antenna we get all three bands as with improved return loss and bandwidth as shown in Figure 6. The three bands which we are getting are better as compared to previous result of microstrip patch antenna with four rectangular slots.

However, there are some limitations which are always associated with every type of design, for example in this case though the Q-factor can be decreased accordingly by lowing the value of dielectric constant but if lowered drastically, it fails to capture enough amount of electromagnetic energy and to act as an efficient resonator.

By using a twister pair of wires the electromagnetic signals generated by the wires cancel each other out due to their opposite polarity.

On old radios the antenna was detrimental to the radio’s operation. Today, the antenna is not necessary. AM radio does not have as good of quality as FM but it can travel farther distances. FM signals can be interfered by things such as mountains or other barrier

According to Cez Verosa at Tech Times.com college students from the University of Leicester found it is possible. It uses heated plasma with high amounts of electromagnetism. You can not see through it though.

The market for wireless communications has experienced incredible growth over recent years and wireless LANs have rapidly become a very

The amplitude affects the strength of the force, that is the length of the force vectors in the electromagnetic wave. The wavelength of the wave depends only on the frequency with which the electron in the transmitting antenna is oscillating up and down; and the speed of light.

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 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.

On a microscopic level, metamaterials are, “An array or ensemble of individual elements called unit-cells, which collectively create a macroscopic response determined largely by the internal composition of the unit-cells” (metamaterialscenter.com). In other words, metamaterial properties are based off the shape, geometry, size, and orientation of the unit cells.

A prototyped plastic breast model was created with the aid of magnetic resonance scans of a typical breast. The dielectric properties of a real breast were mimicked by filling the breast mold with a mixture of water and glycerin in the ratio of 3:22. Afterwards, the breast phantom was submerged in a matching liquid comprising water and glycerin in the ratio of 5:20. Finally, a spherical saline gel target was superimposed on the breast mold as shown in Figure 1 below. Table 1 illustrates the dielectric properties of the target inclusion, breast model and the coupling

Microstrip antenna has quickly evolved from academic novelty to commercial reality with applications in a wide variety of microwave systems. In fact rapidly developing markets in a personal communications systems

By Tribuvan Kumar Prakash Bachelor of Engineering in Electronics and Communication Engineering Visveswaraiah Technological University, Karnataka, 2004. August 2007

In these reflector antennas, the planar reflector antenna is the simplest and yet most practical design. Principle of the planar reflector antenna is image theory. As shown in figure according to antenna image theory, an image antenna can generate in the other side of the perfect electric conducting plane. Using conducting plane as a back reflector, a more compact antenna structure may be feasible. The conducting planar reflector serves to concentrate the radiation to the antenna side of the planar reflector [12].