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

A modified broadband antipodal Vivaldi antenna for the operating frequency range of 6–18 GHz is presented. In order to eliminate diffraction from sharp ends, the corners of the patches are rounded. As a result, both the gain and directivity are improved. Moreover, one major addition that is done to the antenna is the background plane. The purpose of the backplane, which is made of metal, is to reflect any radiation going in a direction opposite to that of the required. This would then effectively increase the forward radiation, thus contributing to the gain of the antenna structure. In addition to be small in size, the designed antenna exhibits stable radiation patterns over the entire operating bandwidth, relatively high gain of 7–8.4 dB, and low cross-polarisation. A prototype of the modified antenna is fabricated and verified experimentally. The measured results are in reasonable agreement with the simulation data. Based on the obtained results, the designed antenna can be useful for broadband applications.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-map.2015.0155

Wideband antipodal Vivaldi antenna with enhanced radiation parameters

In this paper, two compact antipodal Vivaldi antennas (AVA) with improved Radiation Characteristics are presented. U-typed tapered slot edge (U-TSE) AVA and comb-shaped AVA with U-TSE are simulated and optimized. The -10-dB reflection coefficient bandwidth of comb-shaped AVA spans from 2.3 GHz to 18 GHz (7.83~1) and covers 15.7 GHz, while the bandwidth of conventional AVA which has the same dimensions spans from 3.3 GHz to 18 GHz (5.45~1) and covers 14.7 GHz. The U-TSE structure has the capacity to extend the low-end bandwidth limitation and improve the radiation characteristics in the lower frequencies. Compared with the conventional AVA, this modification can miniaturize the electrical size of the AVA antenna about 30%. The results regarding return loss, far field pattern, antenna gain and axial ratio are illustrated.

http://ap-s.ei.tuat.ac.jp/isapx/2013/pdf/48_2_0.pdf

Simulation of two compact antipodal Vivaldi antennas with Radiation Characteristics enhancement

This paper presents a compact antipodal Vivaldi antenna for UWB allocation with band dispersion characteristics. The main purpose of this design is the reduction of three parameter such as transient distortion, reflection co-efficient & surface wave loss. The proposed antenna has the capability to operate over the bandwidth 3-11GHz at return loss <; -10 dB, except the bandwidth of 5-6GHz for WLAN. By cutting Ω-shaped slot in the radiating patch frequency band notch created. The antenna is successfully designed and simulated, it showing broadband matched impedance, stable gain and radiation pattern over a operating bandwidth.

http://dspace.nitrkl.ac.in:8080/dspace/bitstream/2080/1671/1/aravind.pdf

Antipodal Vivaldi Antenna UWB Antenna With 5.5GHz band-notch

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

A simulation of a small sized antipodal Vivaldi antenna for ultra-wideband (UWB) applications is presented in this paper. By using commercial electromagnetic simulation software-Ansoft HFSS, both the simulated and optimized results have been shown for the Vivaldi antenna printed on the substrate of FR4. The results regarding standing wave ratio (VSWR), far field pattern, group delay and antenna gain are illustrated. Good results of radiation patterns, VSWR and gain of Vivaldi antenna are obtained over the UWB frequency band, which made them valuable for short-range, low-power mobile electronics in UWB communication.

Wenming Tian

Papers

Simulation of a small sized antipodal Vivaldi antenna for UWB applications

Multispectral Transparent Electromagnetic-wave-absorbing Optical Window Technology Based on Random Grid