The design of an ultra-wideband antipodal Vivaldi antenna to operate at frequency range from 2.1 GHz-27 GHz for microwave imaging applications is proposed in this paper. It includes regular triangular slits and opening rate of the aperture that extends the lower end of frequency band limitation and improves the radiation characteristics. Good radiation characteristics in terms of improvement of front-to-back ratio and gain are achieved. A prototype of the proposed antenna is fabricated and tested. The result of measurement of magnitude of reflection coefficient is in a good agreement with the simulated result. Feasibility of this antenna for the use in microwave imaging technique to obtain high-range resolution images of construction materials is demonstrated.

Design of Ultra-Wideband Antipodal Vivaldi Antenna for Microwave Imaging Applications

In the last decades, microwave imaging has been a new area of research due to its many advantages over current imaging systems. Microwave imaging system is used for in-depth inspection of biological tissues. The test provides the identification of morphological changes in these biological tissues, as well as their locations. The emerging Ultra-Wideband (UWB) microwave imaging gives better result with the main advantage of using non-ionizing radiation. In these systems, antennas play a very important role, and as such, their optimization has become a very important topic because the device is placed close to the human body. Thus, many aspects are of great importance in the design of the antennas starting from the material with which it is constructed, its dimensions, operation bandwidth, human body influence on the antenna parameters, short-pulse propagation, etc. Recent research has shown several efforts in improving the electromagnetic sensors used in these systems, either as individual or array elements. In this paper, we provide an overview of the most relevant developments in the field of UWB high directivity sensors used in microwave imaging systems.

An Overview of UWB Antennas for Microwave Imaging Systems for Cancer Detection Purposes

In this ultra-wideband antipodal Vivaldi antenna among end fire radiation patterns function at UWB (3.1 GHz to 10.6 GHz) frequency range for radar and microwave imaging application is proposed. This article presents the design of two different types of antipodal Vivaldi antennas, a conventional and a modified antipodal Vivaldi antenna. This paper presents a parametric analysis of each antenna. While designing the proposed antennas, originally a conventional antipodal Vivaldi antenna is presented for a wide impedance bandwidth performance assessment. Furthermore, the Vivaldi antenna is modified by incorporating corrugations on the edges which resulting in gain significantly along with increased directivity in the low frequency band. In addition, the modified antenna offers high gain and flat gain in the operating UWB band. The design and optimization process is carried out using the CST simulation software for parameters performance assessment of return loss, radiation pattern, directivity and input impedance. Prototypes of the two different proposed antennas are fabricated and tested for its return loss and directional pattern.

/pdf/ultra-wideband-antipodal-vivaldi-antenna-for-radar-and-4rcna9xf1m.pdf

Ultra-wideband antipodal Vivaldi antenna for radar and microwave imaging application

An elliptically-tapered antipodal Vivaldi antenna with operating frequency range from 1.65 GHz – 18 GHz designed for microwave imaging applications is presented. It includes comb-shaped slits and opening elliptical rate of top and bottom radiators to lower frequency band limitation of conventional antipodal Vivaldi antenna. It is shown that the antenna gain has been increased by comb-shaped slits at lower frequencies up to 9.5 dBi at 2 GHz and at higher frequencies up to 14.2 dBi at 18 GHz. Feasibility of the proposed antenna for the use in microwave imaging technique is also demonstrated.

UWB elliptically-tapered antipodal Vivaldi antenna for microwave imaging applications

This paper present a recognition technique of metal placed inside and between two walls. A unique scheme of recognition of metallic objects through Ultra Wide Band (UWB) Modified Antipodal Vivaldi Antenna (MAVA) frequency range of (3.1GHz to 10.6 GHz) is presented in this paper.The working mechanism of detection system based on Time Domain Reflectrometry (TDR) using through wall imaging (TWMI). A very small duration pulses generated by Vector Network Analyzer (VNA) which are used for illuminate the wall.The analysis of a system under UWB antenna probe array. The simulation results of MAVA have given an enormous potential of penetration, in order to recognize concealed metal objects with fine precision, proving a smart development in the detection system technology. The improvement of resolution in an image, special filters have been developed and implemented. The design and optimization progression is conceded out via CST simulation software for parametric performance assessment of return loss, radiation pattern and directivity.

/pdf/recognition-of-metal-objects-inside-wall-using-antipodal-2nk1wn5azu.pdf

Recognition of Metal Objects inside Wall using Antipodal Vivaldi Antenna

An antipodal Vivaldi antenna for UWB applications is presented in this paper. The proposed antenna is designed with simple structure but presents very good plot impedance characteristic. In addition, the antenna offers high gain and flat gain in the operating bandwidth from 3.1 GHz to 10.6 GHz. The antenna design simulation has been performed by using the commercially available simulation software HFSS 14. The antenna is fabricated on popular substrate FR4 with a dielectric constant of 4.4 and thickness 1.6 mm. The fabricated antenna has been tested for its return loss and directional pattern, and compared with simulated results.

http://ieeexplore.ieee.org/iel7/6908289/6916663/06916735.pdf

Analysis and design of antipodal Vivaldi antenna for UWB applications

In this paper, a compact antenna for broadband operation is depicted. A C-shaped patch that based on Chuo University's logo is used to design a monopole radiator. Transmission line theory and the resonator model are adopted to analyze the operating frequencies of the proposed antenna. The bandwidth was enhanced by using the curve of C-shaped patch and CPW feeding method. The proposed antenna was designed and simulated successfully by using HFSS 14. The simulation results show that the antenna has compact size 18.6×17.2 mm2, a good impedance band with range from 3.9 to 7.6 GHz for return loss S11 less than -10 dB. The simulated bandwidth reaches 3.7 GHz which is about 72.5% with respect to the center frequency of 5.1 GHz. The antenna can be integrated into wireless communication products such as HIPERLAN/2, IEEE 802.11 a/h/j/n, and WiMAX (4.9-5.85GHz).

Hien Chu Ba

Papers

Analysis and design of antipodal Vivaldi antenna for UWB applications

A compact CPW-fed C-shaped patch antenna for wireless communication