Multimode Vivaldi antenna

Abstract

worth mentioning that these discrepancies are difficult to predict in advance, due to imperfections in the manufacturing process, but can be overcome using external tuning circuits to adjust the operating frequency. Figure 8 shows the simulated and measured radiation patterns in the E plane (X-Y) and in H plane (Y-Z) of the antenna for all modes. The antenna exhibits directional endfire radiation at the angle u 5 908 in all modes and over all the operating frequencies. This is due to the V-shaped form, which privileges radiation in the direction of the V-shape. The simulated and measured gain of single-band mode is 3.3 dBi and 2.96 dBi, respectively. The simulated and measured gains obtained in the wideband, dual-band and triple-band modes are given in Tables (2-4). CONCLUSIONIn this article, a novel directional end-fire antenna switchable between a slot dipole and a tapered slot antenna is presented to achieve multiband and wideband operations have been presented. By using five PIN diode switches in the structure, four modes have been obtained corresponding to a wideband, singleband, dual-band, and triple-band operations. These operations were achieved by activating/deactivating parts of the antenna structure. The proposed design has the benefit of having all the above configurations in the same structure. The simulated and measured results have been demonstrated. The antenna is believed to be useful for multiband applications requiring a stable radiation patterns in the different operating modes. ABSTRACT: In this article, Electromagnetic(EM) measurements campaign in controlled environment (antenna measurement laboratory) carried out to test, theories on EM bistatic scattering from buried metal detection has been presented. Both background signal subtraction algorithms and image processing techniques were applied. For each measurement, the brilliant area (BA), the ratio of pattern area(containing only non-zero points) to the total scan area, has been calculated and formula relating BA with the width of the block, which is the distance from the front face of the block to the location where the metal is embedded, has been established. An average absolute error between calculated BA and measured BA is varying between 2.38% and 4.3%. We generated and proposed a mathematical model for estimating embedded depth, and measurement results are in good track with real one. ACKNOWLEDGMENT

Switchable slot dipole to tapered slot antenna for wideband and multi‐band applications with directional beam patterns

“…Since the inverse scattering problem occurs in a variety of fields such as ultrasonic medical imaging, nondestructive testing for civil engineering and security, military mine detection, industrial applications and possible governmental issues, the detection problem has significance in terms of scientific perspective. Therefore, the issue forces scientists to conduct researches and develop techniques on similar problems [1][2][3][4][5][6][7][8]. Nicholson et al [1] used an improved image-based coherent Doppler tomography (CDT) technique for near-field radar crosssection measurement.…”

“…However, the RCS computed with the CDT method using the simulated near-field data provided a good approximation to the true far-field RCS. Marr et al [2] investigated the scattering characteristic of the metallic sphere by using cylindrical near-field scanning system. They investigated the radar cross section and pattern of the sphere by putting it in the center of the scanner, and RCS of canonical targets derived from near-field measurement are in good agreement with theory.…”

High-gain frequency reconfigurable Vivaldi antenna

“…Some work on reconfigurable Vivaldi antennas has been reported in [5]- [7]. In [5], two rings are introduced to a Vivaldi antenna to obtain narrowband reconfiguration, however the gain that can be achieved is low, only up to 5.93 dBi. In [6], several ring resonators are introduced on the tapered slot to achieve one wide band and three narrow bands.…”

The Band Notch Sensitivity of Vivaldi Antenna Towards CSRRS

“…However, printed monopole antennas generally have unstable radiation patterns in the whole working band, and the radiation may go even worse when adding additional slots. In the meanwhile, Vivaldi antenna cannot be notched easily in most area of its radiation patch [9][10][11], but a bandnotch Vivaldi antenna normally possesses an almost constant endfire radiation within the whole UWB range [12][13][14][15][16].…”