a miniaturized broadband and high gain planar vivaldi

Research ArticleA Miniaturized Broadband and High Gain Planar VivaldiAntenna for Future Wireless Communication Applications

Permanand Soothar ,1,2 HaoWang ,1 Chunyan Xu,1 Yu Quan,1 Zaheer Ahmed Dayo,3,4

Muhammad Aamir,4 and Badar Muneer2

1School of Electronic and Optical Engineering, Nanjing University of Science and Technology (NJUST), Nanjing 210094, China2Department of Electronic and Telecommunication Engineering, Mehran University of Engineering and Technology (MUET),Jamshoro, Sindh 76062, Pakistan3College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics (NUAA),Nanjing 211106, China4Department of Computer Science, Huanggang Normal University, Huangzhou, Hubei 438000, China

Correspondence should be addressed to Permanand Soothar; [email protected] andHao Wang; [email protected]

Received 2 April 2021; Revised 5 July 2021; Accepted 16 July 2021; Published 6 August 2021

Academic Editor: Giuseppina Monti

Copyright © 2021 Permanand Soothar et al. +is is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work isproperly cited.

+is paper presents a new miniaturized planar Vivaldi antenna (PVA) design. +e proposed antenna structure consists of anaperture tapered profile and cavity stub fed with a simple 50Ω strip line feeding network. +e designed PVA offers versatileadvantages, including the miniaturized size and simple design, and exhibited an outstanding performance compared to the latestreported literature. +e antenna occupies a minimal space with an electrical size of 0.92λ0 × 0.64λ0 × 0.03λ0. +e antenna achievesan excellent relative impedance bandwidth 117.25% at 10 dB return loss, peak realized gain of 10.9 dBi, and an excellent radiationefficiency of 95% at the specific resonances. +e antenna’s optimal features, that is, broadband, high gain, and radiation efficiency,are achieved with efficient grooves based approach. Besides, the proposed antenna results are also analyzed in the time domain,which shows the excellent group delay performance <2 ns in the operational band. +e proposed antenna exhibited a stable far-field radiation pattern in orthogonal planes and strong distribution of current at multiple resonances. Simulation and themeasured result show a good agreement. +e proposed antenna has achieved optimal performance and is suitable for futurewireless communication applications.

1. Introduction

In modern wireless communication systems, the imple-mentation and demand of a high data rate transmissionscheme are increasing rapidly [1]. +e antenna systems,which may exhibit optimal performance and cover multiplewireless communication services, are very suitable formodern communication systems. +erefore, in order tofulfill the demand, compact, high gain, wideband, and ra-diation efficient PVA are required. Such antennas are anessential component of the modern communication systemand acquired substantial consideration due to best perfor-mance features, that is, broadband, high gain, radiation

efficiency, and stable far-field patterns, with advantages oflow cost, low profile, and minimal size [2].

Currently, the PVA is a good choice for future wirelesscommunication applications, including ultrawideband(UWB) spectrum [3, 4], intersatellite communication [5],medical imaging [6], notch band [7], wide beam scanningphased array [8], ground-penetrating radar (GPR) system[9], and radar (radio detection and ranging) [10]. +e PVAhas demonstrated broad impedance bandwidth (BW), highgain, good radiation efficiency, and wide beam pattern.Generally, it contains a strip line or microstrip feedlinetransition with radial cavity stub. +e radiating parts of theantenna were erected exponentially, elliptically, linear

HindawiInternational Journal of Antennas and PropagationVolume 2021, Article ID 9912008, 11 pageshttps://doi.org/10.1155/2021/9912008

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https://doi.org/10.1155/2021/9912008

curvatures, and constant width slots [11].+emain concernsfor active researchers related to the antenna designing fieldare mainly the antenna’s large electrical and physical size,narrow impedance BW, moderate gain, and low radiationefficiency. Hence, the prime focus of the antenna designers isto refine the main aspects of the antenna structures, such aswide impedance BW, compact size, gain, radiation efficiencyperformance, and stable far-field radiation features [12].

In the last decade, different structures of the compactplanar antennas were investigated to enhance the antennaimpedance BW, gain performance, and radiation charac-teristics [13]. However, very few antenna designs have acompact size with a tapered profile and can attain the an-tenna’s optimal key characteristics. In the literature, variousantenna geometries, such as slits, tapered slot radiator, andflared transition with modified cavity stubs [14–17] have beenreported. Also, several designs based on different slot shapes[18–20] were suggested to achieve the required gain, ac-ceptable BW, radiation efficiency, and perfect impedancematching. +e reported antennas consist of intricate struc-tures and exhibited a satisfactory performance in terms ofBW, peak gain, and radiation efficiency. +e coplanarwaveguide (CPW) fed bowtie slot antenna with large sizeachieved triple-band response reported in [21]. Awl et al.proposed microstrip antenna for C, X, and Ku band appli-cations with an electrical size of 0.687λ0 × 0.492λ0 × 0.1038λ0at the 9.8GHz [22]. +e presented antenna design comprisedof a semitriangular patch shape with a CPW feedline andattained 107% fractional BW with 5.3 dBi realized gainperformance. Besides, the compact size linear tapered slotantenna design with tilt grooves approach is demonstrated in[23]. +e designed antenna achieved an impedance BW of15.5GHz with broad beam characteristics. A tapered slotantenna (TSA) employing a folded form technique achievedenhanced impedance BW and gain [24]. +e proposed an-tenna design was complex and attained acceptable gain andbroad impedance BW with a large electrical size of4.0λ0 × 2.4λ0 × 0.032λ0.

Another work on TSA was proposed for imaging ap-plications with the size of 2.09λ0 ×1.566λ0 × 0.034λ0 [25]. +eantenna achieved 77% BW and has a larger size. +e authorsproposed antenna array and obtained ∼55% broad BW, andexcellent peak realized gain with antenna size of1.8λ0 ×1.38λ0 × 0.024λ0 [26]. +e substrate integrated wave-guide (SIW) based new shaped antenna with broadbandimpedance BW is reported in [27]. However, the developedantennas reported in the literature were larger in size andemployed a high fabrication process and complicated as-sembly. Another work on high gain bowtie slot antennaachieved the multiple frequency bands [28]. +e proposedstructure was simple and printed on FR4 substrate. +eauthors presented wideband loaded linear TSA with broadbeam width [29]. Besides, the Chang team designed an an-tenna on FR4 substrate with a larger dimension of1.465λ0 × 0.847λ0 × 0.02λ0 and covered 82.2% relative im-pedance BW. +e reported antenna comprises three types ofinverted ℿ (omega-shaped) loaded slots and has a complexstructure with large size. Krishna et al. [30] developed theantenna for S, C, X, and Ku band applications with a compact

size of 2.0λ0 × 2.5λ0 × 0.067λ0 and obtained the impedanceBW of 15GHz with a peak realized gain of 7.0 dBi. However,the work presented in [30] occupied large antenna size withdual exponentially slotted, resulting in computational com-plexity. A compact wideband CPW-fed taper-shapedmonopole antenna with an L-slot has been investigated in[31].+e antenna was realized on FR4 substrate with compactdimensions of 0.395λ0 × 0.355λ0 × 0.0315λ0 and obtained thenarrow BW performance ranging from 3.8 to 8GHz with amodest gain of 3.4 dBi. Another high gain CPW-fed antennais proposed in [32]. +e authors achieved good performancewith a large antenna size.

In this paper, a new miniaturized structure of PVA isdesigned, simulated, and fabricated. +e proposed taperedstructure is erected with alternate grooves based techniquethat obtained the wide impedance BW, high gain, excellentradiation efficiency, and stable far-field radiation charac-teristics. +e proposed antenna has the miniaturized size of0.92λ0 × 0.64λ0 printed on a Teflon™ laminate with athickness of 0.03λ0. A comparison with the recent state-of-the-art work is provided. +e proposed model achieves therelative BW of 117.25% with |S11| better than 10 dB, thepeak realized gain of 10.9 dBi, the excellent radiation ef-ficiency of 95%, good performance of group delay <2 ns,stable far-field radiation pattern in E- and H-planes,and consistent strong current distribution at multipleresonances.

+e main contribution of this paper is as follows:

(i) +e designed PVA is compact in size, overcomes thesimulation and geometrical complexity, and ach-ieves optimal performance

(ii) A robust grooves based method is proposed whichreduces the design and fabrication complexity of theantenna

(iii) +e antenna achieves an excellent relative BW of117.25%, a high realized gain of 10.9 dBi, and ex-cellent radiation efficiency of 95%

(iv) +e proposed antenna results are validated in thetime domain, that is, group delay, which shows theexcellent performance <2 ns across the operablefrequency span

(v) +e proposed antenna exhibits the optimal per-formance features, and their comparison is pro-vided with recently reported literature (comparisonpresented in Table 1), which shows the clearadvantages

+e rest of the article is organized as follows: Section 2presents the suggested design material, antenna arrange-ment, and proposed antenna model strategy. +e impact ofdifferent variable and sketches of surface current distri-bution is also provided in this section. Section 3 offers theanalysis of the simulated and measured results of theproposed antenna. +e peak realized gain, radiation effi-ciency, group delay, and far-field radiation pattern alongthe standard planes are analyzed and discussed in thissection. Finally, the conclusion of the study is explained inSection 4.

2 International Journal of Antennas and Propagation

2. The Proposed Antenna Arrangementand Geometry

In this section, we discuss the designed antenna layout andsimulation results analysis. +e proposed prototype is en-graved on Teflon™ laminate with relative permittivity of 2.1and loss tangent of 0.001. It consists of a top metal plateetched with tapered lines and the radial cavity stub.Moreover, a strip line feeding network with a fan-made stubis used to connect the 50Ω SubMiniature version A (SMA)connector. +e feedline is placed on the bottom of thesubstrate. A high-frequency structure simulator (HFSS)V-17.1 is used to design the proposed structure.+e compactantenna model aims to produce a broad impedance BW,high gain and radiation efficiency, stable far-field patterns,and strong current distribution at multiple resonances.

Figure 1 shows the three-dimensional (3D) view of thedesigned and simulated antenna model, consisting of adielectric substrate, metal plate, and strip line feedlineframework. +e metal plate is etched with tapered lines,slots, and the radial cavity stub, where the strip line feednetwork is connected with a balun cavity stub placed onbottom of the substrate. +e opening tapered profile de-pends on apertureH, and its width must be greater than halfof the free-space wavelength. A slot line is engraved on themetal ground plate with a radius (r1) and a rectangle slot(L1SL) tapered profile depicted in Figure 2.

+e parallel rectangle slot line segment is used to per-form the coupling. Besides, the gradual exponential profileradiates the free space in the steady opening part from theinevitable electromagnetic waves to the tapered aperture(H), which primarily marks the transmission of electro-magnetic waves. +e gradual exponential profile radiates thefree space in the steady opening part from the inevitableelectromagnetic wave to the tapered aperture (H).

In the metal plate, two grooves are introduced with0.3mm width at the opening profile affecting the loweroperating band ranging from 6 to 7GHz. However, thetruncated line is adopted at the 100Ω transmission line toachieve the load terminal matching equal to the groundterminal.

+e linear expression of the exponential tapered profilecurve is determined by

y � c1eRx

+ c2, (1)

where

c1 �y2 − y1

eRx2 − e

Rx1,

c2 �y1e

Rx2 − y2eRx1

eRx2 − e

Rx1.

(2)

Two conical points can calculate the linearly exponentialtapered profile P1(x1, y1) and P2 (x2, y2) and R is specified

Table 1: Comparison of different antenna key features.

Ref. Profile Antenna dimensionsL×W×H (λ0)

Whole dimensions(mm2)

Fractional bandwidth(%)

Max. gain(dBi)

Radiation efficiency(%)

+is work Linearly 0.92× 0.64× 0.03 248.535 117.25 10.9 95

Awl et al. [22] Semitriangularpatch 0.687× 0.492× 0.1038 315 107.69 5.3 US

Zhang et al. [23] Linearly 0.735× 0.965× 0.028 336 112.72 US USArezoomand et al.[24] Linearly 4.0× 2.4× 0.032 6000 100 15 89

Jiang et al. [25] Exponential 2.09×1.566× 0.034 1728 76.92 11.8 USSoothar et al. [26] Linearly 1.8×1.38× 0.024 6210 66.66 10.75 90Wu et al. [27] Exponential 1.28×1.46× 0.02 2574 60.86 8.7 USChang et al. [29] Linearly 1.465× 0.847× 0.02 2082 82.19 US USKrishna et al. [30] Exponential 2.0× 2.5× 0.067 2880 120 7 USNaji [31] Taper shaped 0.395× 0.355× 0.0315 360 71.18 3.4 95US: unspecified.

Metalplate

TeflonTM

dielectric

Feed network

Grooves

Figure 1: A 3D view of the proposed antenna structure.

r1P1

hsub

Length (L)W

2GR

L 2GR

TSL LTA

H

W 1SL

L1SL

P2Widt

h (W

)

Figure 2: +e 3D-geometrical arrangement of the proposed planarVivaldi antenna.

International Journal of Antennas and Propagation 3

by the opening rate of the exponential factor.+e parametersc1 and c2 are determined by the constants of coordinates ofthe opening rate. Besides, the slit line transition is indicatedby the (W1SL) and (W2GR) and strip line transition is statedwith W3FL, W4FL, and W5FL. Moreover, the taper line TSL isdetermined as (x2 − x1) and the height of the aperturesection “H” is 2(y2 − y1) + W1SL. When the opening rate Ris approaching zero, the exponential taper results s0 � (y2 −

y1/x2 − x1) provide the tapered slope. +e taper slope “s”changes continuously from s1 to s2 for the exponential taperdefined by equation (1), where s1 and s2 are the taper slopesat x � x1 and x � x2 and s1 < s< s2 for R> 0.+e angle of thetaper flare is characterized by α � tan−1 s that parametersare interrelated to W1SL, TSL, H, and opening rate R.

+e EM waves uncouple from the tapered profile, andthe structure radiates into free space from the laminate end.For the TSA to radiate appropriately, it has to behave as asurface-wave antenna. To achieve this, the effective dielectricthickness teff � ( ��εr

√− 1) t, where t shows the thickness

parameter of actual laminate must meet the following re-quirements [33]:

0.005λ0 < teff < 0.03λ0, (3)

where λ0 is the free space wavelength at the center frequency.+e thinner the dielectric substrate, the wider the widthwhile the beam width will break if the substrate is thicker.Furthermore, in many wireless applications, alternate fednetwork performance requires a narrower BW [34]. As aresult, different feed networks such as microstrip line, cir-cular cavity stub, and strip line exist. In the proposed design,the strip line feed system is excited through a 50Ω SMAconnector containing the balun stub transformer section, asillustrated in Figure 3. +e proposed antenna structureprovides a broad impedance BW of 6–23GHz with goodradiation characteristics.

Geometrically optimized values of the proposed antennaare illustrated in Table 2.

2.1. Variation in Slot Line Width (W1SL) and Groove Width(W2GR). +is section explains the impedance matching ofthe developed antenna model. +e return loss |S11| plot withvarious values is illustrated in Figures 4(a) and 4(b). It isobserved that the simulated result resonances obtained in-clusive impedance BW performance. +e values range from0.5mm to 0.8mm; the width of the slot line (W1SL) tran-sition is varied. +e best result for impedance matching isobtained at the value of 0.7mm, as shown in Figure 4(a).+ecombination of radial cavity stub and tapered profile is usedto achieve the antenna parameter accuracy. By applying thevariation from 0.1mm to 0.4mm of the groove width(W2GR), the optimum results have been obtained at thevalues of 0.3mm, as illustrated in Figure 4(b).

2.2.CurrentDistribution. Figure 5 shows the surface currentdistribution of the proposed antenna. It can be analyzed thatthe strong current density appears at the higher frequency ofthe operable BW. Figure 5(a) shows the surface current

intensity at the first resonance of 6.6 GHz. +e feed line isexcited by 50Ω SMA connector at the bottom of the sub-strate laminate and transited due to radial cavity and thetaper profile as can be seen from Figure 5(a). Moreover, thesecond resonance point indicated at 12.3GHz shows thehigh current intensity to the slot line and the grooves to thetaper lines as illustrated in Figure 5(b). +us, the currentintensity is very high and is concentrated at the high fre-quency of 20.2 GHz and 22.3GHz, as shown in Figures 5(c)and 5(d).

3. Simulated and Tested Results

3.1. Return Loss |S11|. S-parameters, peak realized gain, andradiation characteristics are the critical antenna output indexes.For an optimal antenna design and its high efficiency, theseinterdependentmetrics need to be balanced. S-parameter of thefabricated structure was measured with a calibrated Agilentvector network analyzer N5244A.+e simulated andmeasuredresults of return loss |S11| are illustrated in Figure 6. +esimulated results showmultiple resonances, indicating that theproposed antenna has achieved comprehensive impedance BWperformance. Although with a slight change in frequency, thesimulated results (black and red curve) have several resonancesobserved at 6.6GHz, 12.3GHz, 20.2GHz, and 22.3GHz.

Moreover, a small variation in calculated and simulatedoutcomes can be seen in Figure 6. +ese inaccuracies areprimarily due to assembly error and experimental

w 3FL

w 4FL

W5FL

L3FL L4FL

L5FL

Hr

L6FLLSTFS

θ1

Φ1

SMA

conn

ecto

r

Figure 3: Geometrical feeding network of the proposed antenna.

Table 2: Assigned geometrical variables along with optimumvalues (mm).Parameters W1SL W2GR W3FL W4FLOptimized value 0.7 0.3 1.55 0.55Parameters W5FL Hr Φ1 Θ1Optimized value 0.5 0.5 120° 40°Parameters r1 L1SL L2GR TSLOptimized value 1.5 2.85 3.68 11Parameters LTA LSTFS L3FL L4FLOptimized value 2.76 3 3.55 2.55Parameters L5FL L6FL hsub WOptimized value 1.55 2 0.6 13.15Parameters LOptimized value 18.9


configuration tolerances. Besides, the antenna fabricatedmodel was fed by a practical SMA connector made of metal(causes losses due to incorrect soldering and parasitic lossesin terms of capacitance and inductance). +erefore, an ac-ceptable difference between the tested and the simulation isobserved. One can control this by using efficient substrates,feeding connectors of high precision, and good qualitycables to monitor performance accuracy. +is slight error inthe calculated results often ensures that the fabricatedprototype is realized. +e fabricated prototype connectedwith the SMA connector is shown in Figures 7(a) and 7(b)which is measured in the anechoic chamber. Furthermore,the measured and simulated return losses across operablefrequency are depicted in Figure 6. It may have been ob-served to cover the wide BW from 6 to 23GHz, that is,(∼117.25%) associated with future wireless communicationapplications.

3.2. Peak Realized Gain, Radiation Efficiency, and GroupDelay. +is section covers the simulated and measuredresult analysis of the radiation efficiency, peak realizedgain, and group delay. +e antenna gain measures howwell an antenna radiates energy in a specific direction. Incontrast, radiation efficiency measures how well an an-tenna uses received power to emit energy in all directions.It can be observed from Figure 8 that the proposed an-tenna achieved the peak realized gain at its maximumvalue. However, due to conductor losses and reduced sizedue to putting a half-wave of wire into a smaller volume,the gain goes below zero for that prescribed frequencyrange. +e interfering radiation caused by the matchingnetwork at these particular frequencies could be the cause

of this gain reduction. Figure 8 shows the simulated andtested comparison of the gain and radiation efficiency ofthe proposed antenna. +e radiation efficiency of theantenna is defined as the ratio of accepted power andradiated power.+e following equation is used to calculatethe measured efficiency:

ηmeas �Gmeas

Dsim, (4)

where ηmeas and Gmeas signify the fabricated prototypemeasured efficiency and gain, respectively, and Dsim de-notes the designed prototype simulated directivity. +eexcellent simulated efficiency of 95% and tested 87% isrealized at the higher frequency at the operable BW.Moreover, the proposed antenna shows a gain of 3.41 dBi atthe first resonance of 6.6 GHz, the noted gain of 3.7 dBi at12.3 GHz, the high gain of 9.35 dBi at 20.2 GHz of thirdresonance, and the final resonance has been obtained at22.3 GHz with an excellent gain of 10.9 dBi. +us, theproposed antenna received the realized gain at its peakvalue at multiple resonances for future wireless commu-nication applications.

Figure 9 depicts the group delay (ns) performance pa-rameter in the context of a time-domain analysis. It is an-alyzed that the proposed antenna exhibited a constant groupdelay of <2 ns across the operable frequency range, con-firming that the antenna has a broadband capability.

3.3. Radiation Characteristics (E and H) Plane. +e two-dimensional (2D) pattern in the E- and H-planes of theproposed antenna was determined inside the anechoic

|S11

| dB

W1SL (1) = 0.5mmW1SL (2) = 0.6mm

W1SL (3) = 0.7mmW1SL (4) = 0.8mm

–40

–30

–20

–10

0

6 8 10 12 14 16 18 20 224Frequency (GHz)

(a)|S

11| d

B

W2GR (1) = 0.1mmW2GR (2) = 0.2mm

W2GR (3) = 0.3mmW2GR (4) = 0.4mm

6 8 10 12 14 16 18 20 224Frequency (GHz)

–40

–30

–20

–10

0

(b)

Figure 4: Return loss |S11| performance against operable frequency range: (a) effect of the width of slot line and (b) effect of the width of thegroove in the taper profile.


chamber room with conditions of far-field. An anechoicchamber environment and the placement of the fabricatedprototype are shown in Figure 10. A cable was attached tothe transmission signal anchorage of a VNA N5244A andthe tunable signal generator with the standard horn antenna.Figures 11(a)–11(c) show the simulated and measured ra-diation patterns in the elevation E-plane (Φ � 0°) andazimuth H-plane (Φ � 90°) at the multiple resonances. +eproposed antenna exhibited stable radiation patterns at

multiple resonances. As required, the E- and H-plane beamdirects itself towards the 0° direction. Besides, it radiates,equally in the other plane.

Similarly, results are stable to display direction aroundelevation plane Φ � 0° and azimuth plane Φ � 90°. It isobserved from Figures 11(a)–11(c) that the measured resultsat different resonances such as at 6.6GHz, 12.3GHz, and20.2GHz and pattern at 0° beam angle in the E- andH-planes are consistent.

2.8017E + 002

1.7291E + 002

1.0671E + 002

6.5858E + 001

4.0645E + 001

2.5084E + 001

1.5481E + 001

9.5540E + 000

5.8963E + 000

3.6390E + 000

2.2458E + 000

1.3860E + 000

8.5539E – 001

5.2791E – 001

3.2580E – 001

2.0107E – 001

Jsurf (A/m)

(a)

2.8017E + 002

1.7291E + 002

1.0671E + 002

6.5858E + 001

4.0645E + 001

2.5084E + 001

1.5481E + 001

9.5540E + 000

5.8963E + 000

3.6390E + 000

2.2458E + 000

1.3860E + 000

8.5539E – 001

5.2791E – 001

3.2580E – 001

2.0107E – 001

Jsurf (A/m)

(b)

2.8017E + 002

1.7291E + 002

1.0671E + 002

6.5858E + 001

4.0645E + 001

2.5084E + 001

1.5481E + 001

9.5540E + 000

5.8963E + 000

3.6390E + 000

2.2458E + 000

1.3860E + 000

8.5539E – 001

5.2791E – 001

3.2580E – 001

2.0107E – 001

Jsurf (A/m)

(c)

2.8017E + 002

1.7291E + 002

1.0671E + 002

6.5858E + 001

4.0645E + 001

2.5084E + 001

1.5481E + 001

9.5540E + 000

5.8963E + 000

3.6390E + 000

2.2458E + 000

1.3860E + 000

8.5539E – 001

5.2791E – 001

3.2580E – 001

2.0107E – 001

Jsurf (A/m)

(d)

Figure 5: Surface current distribution at multiple resonances. (a) Resonance at 6.6 GHz. (b) Resonance at 12.3GHz. (c) Resonance at20.2GHz. (d) Resonance at 22.3GHz.


3.4. Study of Contrasts. Table 1 provides a comparison of theantenna main features with the existing state-of-the-artwork. +e excellent BW and moderate gain antennas for C,X, and Ku band applications were studied in [22, 30] thatemployed large space. +e SIW based tapered slot antennawas investigated in [27], which occupied a large size. +epresented antenna provided ample dimensions with aprolonged fabrication process and complicated assembling.Furthermore, a tapered slot array antenna for underwatercommunications was investigated in [26]. +e presentedantenna covered the microwave band of 4.0GHz–8.0GHzwith a large physical size. In [29], a wideband loaded tapered

antenna with a broad beamwidth and improved FBR wasinvestigated. +e technique used a wideband loaded threetypes ofℿ slots technique with plenty of space.+e reportedworks were time-consuming and complicated. In this re-search, the groove technique is used, and broad BW isachieved. Due to the trade-off between the antenna keyfeatures presented and results published in the literature, it isdetermined that the performance analysis results would notbe better than the obtained results of the antenna presented.It is concluded that the antenna’s approach can producewide BW, high gain, stable far-field patterns, and strongcurrent flow across the tapered profile.

Simulated return lossMeasured return loss

|S11

| dB

–50

–40

–30

–20

–10

0

6 8 10 12 14 16 18 20 224Frequency (GHz)

Figure 6: Simulated and measured return loss (dB) across the operable frequency span.

(a) (b)

Figure 7: Fabricated prototype of antenna structure: (a) front view and (b) rear view.


2

1

Gro

up d

elay

(ns)

0

4 6 8 10 12Frequency (GHz)

14 16 18 20 22

Simulated resultMeasured result

Figure 9: Simulated and measured group delay (in nanoseconds) over the operable frequency.

Simulated peak realized gain (dBi)Measured peak realized gain (dBi)Simulated radiation efficiency (%)Measured radiation efficiency (%)

Real

ized

gai

n (d

Bi)

Radi

atio

n effi

cien

cy (%

)

–15

–10

–5

0

5

10

15

6 8 10 12 14 16 18 20 224Frequency (GHz)

40

50

60

70

80

90

100

Figure 8: Simulated and tested peak realized gain and radiation efficiency over operable frequency span.

(a) (b)

Figure 10: Antenna tested anechoic chamber environment at NJUST campus.


4. Conclusion

In this paper, miniaturized broadband and high gain PVA ispresented. +e proposed structure comprises Teflon™ di-electric substrate, taper section, and strip line feedline withcavity stub.+e feedline section is soldered with a standard50Ω SMA connector. +e single tilt groove was engravedon the top of the taper profile, which improved the pro-posed structure impedance BW performance. +e wide-band antenna possessed the compact dimension of

0.92λ0 × 0.64λ0 × 0.03λ0. +e proposed antenna has beenfabricated and tested in a real-time environment. +eantenna exhibited a good relative impedance BW of117.25%, and the peak realized gain of ∼10.9 dBi at higherresonances. Moreover, the antenna structure exhibitedexcellent radiation efficiency of 95% and better perfor-mance of group delay (<2 ns) in the time domain. Stableradiation pattern performance and vigorous current in-tensity of the antenna were realized at multiple resonances.Finally, the proposed antenna key characteristics have

0

30

60

90

120

150180

210

240

270

300

330

Simulated E-plane at 6.6GHz

Measured E-plane at 6.6GHzSimulated H-plane at 6.6GHz

Measured H-plane at 6.6GHz

20

0

–20

–40

–60

–80

–100

–80

–60

–40

–20

0

20

Nor

mal

ized

gai

n (d

Bi)

(a)

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30

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150180

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330




20

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–20

–40

–60

–80

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–60

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gai

n (d

Bi)

(b)

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150180

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200

–20–40–60–80

–120–100

–100–80–60–40–20

020

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ized

gai

n (d

Bi)

(c)

Figure 11: (a–c) Tested and simulated radiation patterns due to the E-H plane of the proposed antenna design.


been compared with the recent state-of-the-art work. +edesigned antenna offers versatile advantages and exhibitedoptimal performance features making it a suitable can-didate for future wireless communication applications.Besides, the proposed PVA may be further extended towideband and high gain antenna array topology with anefficient Wilkinson power divider approach.

Data Availability

+e data used to support the findings of this study are in-cluded within the article.

Conflicts of Interest

+e authors declare that there are no conflicts of interestregarding the publication of this manuscript.

Acknowledgments

+e authors Permanand Soothar, Dr. Hao Wang, ChunyanXu, and Yu Quan greatly acknowledge the technical supportand help extended by the rest of the authors in finalizing themanuscript.

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a miniaturized broadband and high gain planar vivaldi

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