Design Challenges : The Desired Operating Frequency

The different forms of antenna technology refer to single or multiple inputs and outputs. These are related to the radio link. In this way the input is the transmitter as it transmits into the link or signal path, and the output is the receiver. It is at the output of the wireless link.

This antenna is designed on FR-4 substrate. It has dielectric constant 4.4 and thickness 1.6 mm. copper material is used for ground plane and patch. We provided microstrip line feeding to this antenna.

The bandwidth limitation of antennas is usually linked to their input impedance because it is the quantity which changes with frequency so improvement in impedance response can help us to enhance its bandwidth. This approach can be implemented into following broad categories:

Due to the time domain sampling effect, the discrete time channel impulse response is given by

these subcarriers to a higher frequency band. Except for a multiplying constant (1=N), the above

A later development of radar technology was the use of Microwave radio transmissions to identify enemy aircraft. A cavity magnetron produced the microwaves, and the British reduced these in size so that they could be carried in aircraft (Sheehan 42).

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

This experiment is based on the acquisition of 3D microwave data at multiple planes. In this regard, reconstructed 3D microwave images will be evaluated using cross-plane and in-plane data (with [9 × 3] – 2] × 240 measurements + 3 consecutive planes). In contrast, reconstructed 2D images will be solely based on in-plane data (with 9 ×240 measurements and 16 antennas of equal height).

In this ideal system shown in figure 2-1 below, the antenna, ADC/DACs, and computer are capable of processing any radio signal of interest in real-time.

The errors of the inverted models were calculated to quantitatively compare the accuracy of individual and joint inversions. The errors within the P-wave velocity and permittivity model are basically unchanged in the individual and joint inversions, whereas the error within the conductivity model in the joint inversion is less than that in the individual inversion. As shown in the Example 1, the structures of P-wave velocity and permittivity model are slightly altered in the joint inversion. Therefore, the errors in these two models also changed slightly. However, the structure and parameter values of the conductivity model are significantly altered in the joint inversion in a way to significantly improve the error of this model. In this joint FWI procedure, the cross-gradient terms are controlled by small weighting factors and cannot dominate the optimization of parameters. Therefore, the structure of each model will change towards those of other models, if the enforced structural constraint is beneficial for the optimization process. In contrast, the effect of structural constraint will decrease during iteration, if it hinders the

This report is on brief discussion of What is Radar and how does it work. Also we will look after how it effects on the society.

A Method for Efficiency Enhancement and Size Miniaturization in the design of UWB Planar Antennas

The concept of MSAs was first proposed by Deschamps in 1953. A patent were issued in France in 1955 in the names of Gutton and Baissinor. After the 1970, the research publications started to flow within the appearances of the first design equation. Since the, different authors started investigation on microstrip patch antennas like James hall, David M. Pozars and there are also some who contributed a lot. Throughout the years, the authors has dedicated there investigations to create a new designs or variations to the original antenna that, to some extent; produce either the wider bandwidth or the multiple frequency operation with in a single element. However most of these innovations bear some disadvantages related to size, height,width or overall volume of the single element and the improvement in the bandwidth suffers usually from degradation the other characteristics.

Antenna is the main component of every communication system. The design of UWB antennas is one of the major factors affecting the progress of UWB technology. As a result, UWB antenna design has been studied much in recent years. UWB antennas must be electrically small and inexpensive without compromising on performance. Omni directional radiation pattern is desired in order to be well suited for ad hoc networks with arbitrary azimuthally orientations. Gain flaterns and phase linearity, i.e., constant group delay, are also required for an UWB antenna in order to not distort the waveform of an ultra narrow-on the order of nanoseconds-electromagnetic energy pulse. In addition, the time domain impulse response is another important criterion of UWB antenna performance. The antenna must transmit UWB signal with minimal dispersion effect. In this thesis all the antennas have been simulated in ANSOFT HFSS-13. This chapter contains the final design of antennas, the parasitic study of antenna in term of impedance band width. The peak gain, radiation efficiency, peak directivity has been calculated in whole operating band and radiation pattern at some frequencies has been studied. The time domain analysis also has been done in this chapter. The total design of antenna include the two parts- first is the designing on the software and second one is hardware part where the testing of the antenna is done on the Vector Network Analyzer (VNA).