Compact Antipodal Vivaldi Antenna Research Articles

Near field food contamination detection technique employing a compact Antipodal Vivaldi antenna

This paper presents a simple yet robust technique for identification of the presence of contaminants in food samples by detecting the variation in the transmission coefficient (S21) in a near field measurement setup. A compact step-notched antipodal Vivaldi antenna with a frequency range of operation 3 - 18 GHz, and realized gain of 12.81 dB at 16 GHz having compact dimensions 60mm×40mm×0.51mm, i.e., 0.6×0.4×0.005λ03 (where λ0 is the free space wavelength at the lowest frequency of operation) is designed for contamination detection due to its compact size, high directivity and high boresight gain for near-field measurement. An equivalent image is constructed from the S - parameters, measured at different positions and different antenna polarizations over the frequency range of 3-18 GHz for metallic contaminants, i.e., iron ball and aluminum foil. An algorithm is developed for detection of contamination from the images using the reference case of no-contamination scenario. The proposed algorithm is validated using full-wave simulation.

A corrugated and lens based miniaturized antipodal Vivaldi antenna for 28 GHz and 38 GHz bands applications

Abstract The paper presents a dualband and compact antipodal Vivaldi antenna (AVA) array by using a dielectric lens (DL) and corrugations for 5G applications. The proposed novel antenna provides very high efficiency and it alleviates beam titling very effectively. Its efficiency is in the range of 95.93%–97.52% whereas the H plane beam titling is ± 1 ° $\pm 1{}^{\circ}$ over most of the frequency range. The antenna frequency response is improved by incorporating corrugations which results in the antenna miniaturization. The designed AVA array size is 2.86 × 3.58 × 0.06 λ g 3 ${{\lambda }_{g}}^{3}$ (for lower guided frequency). The proposed dualband antenna operates from 24.17 GHz to 29.37 GHz and 30.76 GHz to 40.58 GHz. These frequency bands cover 28 GHz and 38 GHz bands of 5G communications. Next, the front-to-back ratio is improved significantly which further results in the gain enhancement. Also, the grooves in the feeding network minimize reverse power reflections. The radiation pattern is stable and it shows that the designed antenna is a directional antenna. The antenna is designed, simulated, and tested by using a network analyzer and anechoic chamber. The testing and simulated results indicate that the proposed AVA array is the best candidate to integrate it in 5G devices.

Compact antipodal Vivaldi antenna design with gain enhancement and notched-band characteristics based on D-CRLH metamaterial

A novel compact ultra-wide band (UWB) antipodal Vivaldi antenna with band notched is presented in this communication. T-shaped slot is introduced to extend the lower end limitation of the frequency band from 1.65 GHz to 1.25 GHz, the miniaturization of the antenna is realized. Then a new thought of the gain enhancement, namely the substrate cutout (SCO) is demonstrated to increase antenna gain, which makes the electromagnetic wave get rid of the bondage of the substrate, reducing the edge diffraction, and thus radiates more effectively, without changing the overall dimension of the antenna. The advantage is of great value in limited space especially. Then a compact unit cell based on Dual Composite Right-Left Handed (D-CRLH) metamaterial is proposed to realize the notched band characteristics in the WLAN band (4.95–5.15 GHz). In addition, the passband would be less affected by the notched band due to the sharp transition band between notched and operating band. Finally, the antenna is successfully simulated and measured, it shows broadband matched impedance, stable gain and radiation pattern over the operating band. The experimental results are also given and show a good agreement with the simulated results.

A Constant Gain and Miniaturized Antipodal Vivaldi Antenna for 5G Communication Applications

This paper proposes a stable gain and a compact Antipodal Vivaldi Antenna (AVA) for a 38 GHz band of 5G communication. A novel compact AVA is designed to provide constant gain, high front to back ratio (FBR), and very high efficiency. The performance of the proposed AVA is enhanced with the help of a dielectric lens (DL) and corrugations. A rectangular-shaped DL is incorporated in conventional AVA (CAVA) to enhance its gain up to 1 dBi and the bandwidth by 1.8 GHz. Next, the rectangular corrugations are implemented in CAVA with lens (CAVA-L) to further improve the gain and bandwidth. The proposed AVA with lens and corrugations (AVA-LC) gives a constant and high gain of 8.2 to 9 dBi. The designed AVA-LC operates from 34 to 45 GHz frequency which covers 38 GHz (37.5 to 43.5 GHz) band of 5G applications. Further, the presented AVA-LC mitigates the back lobe and sidelobe levels, resulting in FBR and efficiency improvement. The FBR is in the range of 12.2 to 22 dB, and efficiency is 99%, almost constant. The AVA-LC is fabricated on Roger’s RT/duroid 5880 substrate, and it is tested to verify the simulated results. The proposed compact AVA-LC with high gain, an improved FBR, excellent efficiency, and stable radiation patterns is suitable for the 38 GHz band of 5G devices.

A compact antipodal Vivaldi antenna with metamaterial half-lens for beam control

A compact antipodal Vivaldi antenna (AVA) with metamaterial half-lens (MHL) for beam control is proposed. The proposed AVA has three different beam forms in the operating frequency band, including end beam from 3 GHz to 9 GHz, beam splitting at 12.2 GHz, and beam deflection at 13 GHz. Furthermore, it can perform beam scanning by adjusting operating frequency from 12.7 GHz to 13.5 GHz. The simulation indicates that the proposed AVA has a −10 dB impedance bandwidth of 143.6% (2.3–14.0 GHz) and a −3 dB gain bandwidth of 100% (4.5–13.5 GHz), which is consistent with the experimental results. Besides, the gain of the proposed AVA has an improvement of about 2 dB in the working band. As a new method to control the beam, the loading of MHL realizes the design of a small size and multi-function antenna, which can be widely used in wireless communication systems.

Improved radiation characteristics of compact antipodal Vivaldi antenna with the hybrid technique for UWB applications

ABSTRACT A compact antipodal Vivaldi antenna with stable end-fire radiation properties over the bandwidth of more than 15:1 is proposed for UWB applications. The gradient titled corrugated edges used to redistribute the antenna surface electric fields are employed to extend the low-end cutoff frequency and increase the low-frequency antenna boresight gain. The asymmetric parasitic patch composed of two triangular patches with different height is introduced to couple more energy from radiating arms of the antenna and thus enhancing mid- and high-frequency gain. The proposed antenna is designed and optimized in detail. To validate the proposed design, a prototype is fabricated and measured. The simulation results are in good agreement with the experimental data. Measurement results show that, the gain variation of the proposed antenna is in the range of 5.4–13.7 dBi over 2.88–40 GHz with the a compact dimension of 40 mm×73 mm×0.508 mm. The compact dimension of the antenna makes it a good candidate for UWB applications.

Binomial stub loaded compact Vivaldi antenna for superwideband applications

AbstractA compact antipodal Vivaldi antenna with superwideband characteristics is presented in this paper. For improved matching of input impedance at lower frequency region, techniques like binomial tapering of outer edges, binomial slit loaded outer edge, and protruded binomial tapered stub loading have been adopted. The antenna operates in a wide frequency range from 2 to 20 GHz. Experimental results show, stable radiation pattern with peak realized gain of more than 8 dBi, group delay within 1 ns, 164% fractional bandwidth, radiation efficiency of more than 90%, which are in good agreement with the simulated results. The compact size of the proposed antenna (1.14λ0 × 1.21λ0) with wide frequency bandwidth and directional radiation characteristics make it suitable for through-wall radar and medical imaging applications.

UWB radar cross section reduction in a compact antipodal Vivaldi antenna

This paper presents the design of a compact antipodal Vivaldi antenna (AVA) with reduced radar cross section (RCS) for directional UWB communications. The impedance characteristics of a conventional AVA are improved by introducing a BALUN taper in the ground plane and circular slots of different diameters in the wings of the AVA. The slots on the wings improve the RCS performance of the antenna by rejecting the orthogonal radiations from the AVA. Furthermore, drills of suitable diameter are introduced to further enhance the monostatic RCS performance. The proposed AVA offers 74% size reduction compared to the existing AVAs reported in literature with its bandwidth extending from 3 GHz to over 12 GHz. The prototype AVA is fabricated and the simulation results are verified using experimental measurements. The prototype antenna offers at least 11 dB reduction in RCS throughout the operating bandwidth with a peak reduction of 16 dB at 7 GHz and 11 GHz.

Antipodal Vivaldi Antenna Arrays Fed by Substrate Integrated Waveguide Right-Angled Power Dividers

This paper describes a novel feed system for compact antipodal Vivaldi antenna arrays on a single layer of substrate integrated waveguide (SIW) by using SIW H-plane right-angled power dividers. The proposed antenna systems are composed of a Vivaldi array and an H-plane right-angled corner power divider which includes an over-moded waveguide section. Based on the number of antennas in the Vivaldi array, mode converter sections at K-band and Ka-band frequencies are designed, fabricated, and measured when feeding Vivaldi antenna arrays with two, three, and four antennas. Right-angled SIW power dividers are employed to obtain controllable phase distribution over the output ports which consequently controls the beam shapes of the systems. The phase relationships in the output ports are varied to obtain different pattern directions for different applications. The two-way divider system with 180-degree phase difference and three-way divider system are fabricated and measured; simulation results are presented for other designs. The measured results are in good agreement with simulations which confirms the design approach. All systems achieve good performance and meet all design goals including a return loss better than 10 dB in the operating bandwidth, gain higher than 8 dB for all systems, and radiation and polarization efficiencies higher than 80% and 98%, respectively.

Compact antipodal Vivaldi antenna with rectangular slots and shaping of flare to cover 6 to 18 GHz

ABSTRACTThe compact antipodal Vivaldi antenna (AVA) with regular rectangular slots in the taper region is presented in this paper intended for electronic warfare applications. The antenna has a simple configuration with compact size. Micro strip line feeding is employed. The rectangular slots at regular intervals and terminal elliptical shaping of taper on top and bottom layers of antenna substrate enhance impedance bandwidth. The slot loading in the taper portion also enhances the gain. The novel feature of this antenna is its small aperture size which is 25 mm. Small aperture size is required for array applications to avoid grating lobes and element pattern nulls. A return loss of less than −10 dB (VSWR <2.0) is obtained over 6 to 18 GHz. The antenna is designed using Ansoft HFSS software and the same is implemented in hardware. Return loss, radiation patterns, and gain have been measured and results reported.

Bandwidth Enhanced Antipodal Vivaldi Antenna for Wide Band Communication Applications

Objectives: To design high bandwidth and high gain compact antipodal Vivaldi antenna which can be applied for modern communication systems especially for military communication systems. Methods/Analysis: Antipodal Vivaldi antenna is designed with flared elements on both sides of the substrate. Top side patch element is oriented towards left side and bottom side defected ground structured element is oriented towards right side. Finite element method based HFSS-15 is used in the design and simulation. The simulated EM-Results of the return loss, VSWR, radiation patterns and field distributions are analyzed and optimized antipodal vivaldi antenna is designed with parametric analysis. Fire resistance PCB substrate material with dielectric constant 4.4 is used as substrate to prototype the antenna model and measured results are analyzed for validation on ZNB 20 vector network analyzer. Findings: In this work a novel antipodal Vivaldi antenna is designed to operate between L to KU-band communication and applications. The proposed antenna modal consisting of a special type of tapered slot edge structure in the design which enhanced the bandwidth of the antenna. To convert antenna into a wide band model, some modifications are done by placing slotted sections on the ground and patch elements. Antenna is showing 15 GHz huge bandwidth and impedance bandwidth of more than 65%. The proposed antenna is showing VSWR of 2:1 ratio in the operating band and peak realized gain of 7 dB. Omni directional radiation pattern with peak directivity of 5 dB is attained with the current model. Wideband characteristics with considerable gain grouping this antenna in to several communication applications in S, C, X, Ku-bands. Novelty/Improvement: Novelty with respect to defected ground structured flared element and huge bandwidth are advancements in the current design. Both patch and ground structures are designed in a way to enhance the bandwidth as well as gain which is advantageous in communication applications. Field distributions with excellent radiation characteristics are making this model as suitable candidate for future communication systems.

A Compact High-Gain and Front-to-Back Ratio Elliptically Tapered Antipodal Vivaldi Antenna With Trapezoid-Shaped Dielectric Lens

A modified compact antipodal Vivaldi antenna is proposed with good performance for different applications including microwave and millimeter wave imaging. A step-by-step procedure is applied in this design including conventional antipodal Vivaldi antenna (AVA), AVA with a periodic slit edge, and AVA with a trapezoid-shaped dielectric lens to feature performances including wide bandwidth, small size, high gain, front-to-back ratio and directivity, modification on E-plane beam tilt, and small sidelobe levels. By adding periodic slit edge at the outer brim of the antenna radiators, lower-end limitation of the conventional AVA extended twice without changing the overall dimensions of the antenna. The optimized antenna is fabricated and tested, and the results show that S 11 <; -10 dB frequency band is from 3.4 to 40 GHz, and it is in good agreement with simulation one. Gain of the antenna has been elevated by the periodic slit edge and the trapezoid dielectric lens at lower frequencies up to 8 dB and at higher frequencies up to 15 dB, respectively. The E-plane beam tilts and sidelobe levels are reduced by the lens.

A Compact Antipodal Vivaldi Antenna for UWB Applications

A compact antipodal Vivaldi antenna (AVA) with the dimension of 42 ×36 ×1.6 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> is proposed in this letter. Structural modifications in the radiating fins have increased the electrical length thereby reducing the lower operating frequency from 5.2 GHz to 3.7 GHz. Proposed antenna maintains -20 dB copolarization to cross-polarization ratio throughout the operating bandwidth. The prototype is fabricated and the measurement results are presented to validate the performance of the proposed AVA.

A Small Antipodal Vivaldi Antenna for Ultrawide-Band Applications

A compact antipodal Vivaldi antenna for ultrawide-band (UWB) applications is proposed. The antenna operates across the entire UWB spectrum from 3.1 to 10.6 GHz, and also has low cross-polarization levels and reasonable gain values over the same frequency band. Two different substrates, Rogers RO3006 and FR4, are considered, and results regarding return loss, far field pattern, phase response, group delay, and gain are presented.