A triband slotted bow-tie wideband THz antenna design using graphene for wireless applications

Accepted Manuscript Title: A triband slotted Bow-tie wideband THz antenna design using graphene for Wireless Applications Authors: Gaurav Bansal, Anupma marwaha, Amanpreet Singh, Rajni Bala, Sanjay marwaha PII: DOI: Reference:

S0030-4026(19)30532-7 https://doi.org/10.1016/j.ijleo.2019.04.063 IJLEO 62716

To appear in: Received date: Accepted date:

12 February 2019 10 April 2019

Please cite this article as: Bansal G, marwaha A, Singh A, Bala R, marwaha S, A triband slotted Bow-tie wideband THz antenna design using graphene for Wireless Applications, Optik (2019), https://doi.org/10.1016/j.ijleo.2019.04.063 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

A triband slotted Bow-tie wideband THz antenna design using graphene for Wireless Applications GauravBansal*1, Anupma marwaha2, Amanpreet Singh3, Rajni Bala 4, Sanjay marwaha5 Training Officer & Principal*1, Professor2, 5, Deputy Controller of Examination3, Assistant Professor4 NSTI Mohali, Punjab, India*1, SLIET Longowal, India2, 5, IKGPTU Jalandhar, India3, NIT Kurukshetra, India4

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Contact Number: 94177-10001*1, 98722-240552,94780980193, 94637-070004, 98722-230555 Fax No. 01672280057*1 [email protected]*1, [email protected], [email protected], [email protected], [email protected]

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ABSTRACT A graphene based triband slotted bow-tie THz antenna is designed and simulatedover anultra wide-band (UWB) of frequencies for modern wireless communication systems. Nanomaterial such as graphene having a number of desirable electromagnetic and mechanical properties can play a significant role in a well defined shape of bow-tie antenna. The electromagnetic properties like S11 parameters, VSWR, gain, realised gain, directivity, input impedance, axial ratio, radiated power, accepted power, efficiency and the radiation properties of such antenna are investigated through finite element method (FEM) based high frequency simulator software (HFSS) which is a commercially available electromagnetic simulator. By incorporating a new nanomaterial such as graphene for slotted bow-tie structure on silicon dioxide substrate with thickness of 3μm and permittivity of ε r= 4 is resonate in triband in THz region. The simulation results show that the radiation efficiency of this bow-tie is 71%, 18.194 dB directivity and 17.529 dB realized gain at 11.1 THz resonating frequency.

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Keywords: Graphene, Nano-antenna, Terahertz Regime, HFSS, FEM,Slotted bowtie antenna.

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1. Introduction

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For applications that require coverage over a broad range of frequencies, such as remote sensing, satellite, television reception of all channels, wireless communication and radar wide band antennas are needed. There are numerous antenna configurations, especially of arrays, fractal antenna; the log periodic has a similar self similar construction that can be used to produce wide bandwidth. Conventional wideband antennas are often spacious, bulky and have a complex design. Chu explored fundamental limits on antenna size, bandwidth and efficiency [1]. According to Chu, antenna will have the widest bandwidth when that they utilize the most space within the circumscribing sphere.The emerging applications in the field of terahertz communication systems demand for the development of miniaturized devices which would be capable of transmitting and receiving the data at low power, the highest possible data rates and the ultra wide bandwidth [2-3]. The growing demand of high data rate at terahertz communication systems is bringing attention of researchers to the unallocated region of frequency spectrum i.e. the terahertz band or spectrum.THz spectrum was called for a long time THz-gap due to the difficulty in bridging theelectronics and the optics technologies. During the last decade, these two technologies have been closing the THz spectrum through the effort of building suitable sources and detectors Therefore; the THz electromagnetic band does not have a standard definition yet. There is adebate among researchers defining the standard THz band, some define the THz band between 0.1THz to 10THz and others between 0.3THz to 30THz. Consequently,

researchers find that the THz band range of 10-30THz exceeds the far-IF band from the well-defined optical technology. In this paper, the standard definition for the THz electromagnetic band is established between 0.1 to 10 THz [4]. In the THz band, with the development of the nanomaterial such as graphene used as THz antennas research, lots of wideband antenna designs have emergedin modern day wireless communication systems [5-10]. Considering the constraints of space, cost,design complexity, and application, many wideband antennas have been designed. The radiation and reception of this wideband signals can be efficiently done by various classical wideband antennas such as spiral, bowtie, Archimedean, Vivaldi etc. Furthermore, other well-known UWB antennas have also received significant attention for better generation and detection of THz radiation. A comparative study of three types of wideband antennas namely bowtie antenna, vivaldi antenna and spiral antenna based on few parameters such as bandwidth, input

impedance, gain and directivity pattern give some interesting results [11]. Considering all those constraints the planar slotted bowtie antenna is the best choice for the wideband applications, which is the focus of this paper.The paper is organized as follows. Section 2 deals withthe graphene based slotted bowtieantenna. Simulated results and discussion is then carried out in Section 3. Section 4 discusses the conclusion followed by the references.

2. Materials and Method The slotted bowtie shaped finite graphene patch can be extracted by cutting an infinite graphene sheet. Depending on the

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edge shapes of structure obtained it can attain any of the two configurations namely zigzag and armchair preserving their inherent electronic properties. From the analysis performed in previous literature zigzag arrangement has been observed to provide better radiation characteristics and hence is considered in this paper [12]. The paper presented here performs the modeling of graphene material as patch using finite element method (FEM) based high frequency structural simulator (HFSS) software. The physical properties of graphene are used to facilitate the inclusion of graphene material in HFSS software characterized by the appropriate physical, thermal and electrical properties [13-17]. To investigate the electromagnetic properties of a single layer graphene, it modeled regarding of the surface conductivity of graphene indicating the frequency-dependent behaviour of graphene conductivity based on Kubo’s formula. The numerical solution is obtained at room temperature (T) = 300 oK, relaxation time (τ) = 0.1 ps, and chemical potential (μ c) = 0 eV [18].The design idea emphasizes on high directive antenna in terahertz region using graphene to operate the antenna in a large band of frequencies of wideband antennas and it is achieved with highly directive inclusion of slotted bowtie antenna.The crosssectional view of slotted bowtie graphene patch antenna is shown in Fig. 1 (a).The dimensional parameters of the proposed antenna are selected to operate in thefrequency range of 1-15 THz as described in Table 1.

3a√εr

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2π√εr

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Theinnerwidth of slotted bowtie antenna is ''WI'', outer width of bowtie antenna Wo, and arm length of bowtie antenna LAprinted on a silicon dioxidesubstrate of thickness ''h'', having a relative dielectric constant of ''εr'' with substrate length of Ls and width of Wsas shown in Fig.1 (b). The graphene based slotted bowtie antenna is designed here to operate at 7.1 THz, 11.1 THz and 13.1 THz. The resonant frequency for bowtie antenna matching to various modes can be given by [1920] ck 2c fr = mn = √m2 + mn + n2 … (1.1)

k mn =

4π√m2 +mn+n2 3a

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wherea is the side length of the bowtie strip, c is velocity of light in free space = 3× 108 m/s, fr is the resonance frequency,kmn is the resonating modes m and n are modes given by … (1.2)

fr =

2c 3a√εr

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The dominant resonant frequency for lowest order mode is hence given by [21] … (1.3)

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A number of suggestions have been made by various researchers with regard to how to modify the triangular microstrip patch antenna to yield an accurate modeling of bowtie antenna that is enclosed by nanomaterial such as graphene. The graphene based slotted bowtie antenna is a planar version of the finite biconical antennawhich can easily be printed on a silicon dioxide substrate. As the existing are consist of slot at the triangular design of the bowtie, the antenna has some bandwidth limitation compared to the 3D biconical and discone antennas. Still, the bow-tie antenna shows good impedance behavior across a wide band and higher directivity and gain. An expression for a eff has been given for the simulated and theoretical results at the resonant frequency for given THz antenna. It is given by [22] Resonant frequency dominant mode is: 2c f10 = … (1.4) 3fr √εr

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Side length of bowtie antenna a=

2c

Effective value of side length of bowtie antenna is a eff = a + Effective dielectric constant εreff =

εr +1 2

… (1.5)

3fr √εr

+

ℎ

… (1.6)

√εr εr −1 4√1+12

h 𝑎

where h is the height of substrate and an is the side length of bowtie antenna.

… (1.7)

Bowtie antenna is a simple version of planar slot antennas which can offer large bandwidth. Fig. 1 shows the geometry of the adopted design.For desired operating frequency, the bowtie antenna is designed with arm length as LA, outer width of bowtie antenna Woand substrate length of Lsand width of Ws, calculated as follows [19] 1.6λ0

LA = Wo =

LS = 𝑊𝑆 =

… (1.8)

2√∈r 0.5λ0

… (1.9)

√∈r b

… (1.10)

0.85

c

… (1.11)

0.45

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3. Graphene based Slotted Bowtie Antenna Simulation

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In this section, present the slotted bowtie antenna simulation results. The validity of this model ishighlighted by comparing the results of gain and directivity with those obtained by the finite element of method. Fig. 1 represents structure of slotted bowtie consists of two triangular patches arranged such that one is mirror image to another consist of graphene material layer on a Sio2 substrate having a relative dielectric constant of ε r=4.0 with substrate length of Ls= 40μm,width ofWs = 40μm, andthe substrate height h= 3μm. The inner width of bowtie antenna WI is 0.22 μm, outer width of bowtie antenna Wo is 7.89 μm, and port gap width is 0.44 μmand arm length of bowtie antenna LA is 8.76 μm. Usually an excitation port is a type of boundary condition that permits energy to flow into and out of a structure. Lumped port is generally an internal excitation. Port must lie in a single plane. This simplifies the description of the behavior of spatially distributed physical systems. For the excitation of the proposed antenna is fed with lumped port and radiates waves at the THz frequencies. To investigate the characteristics of the graphene-basedslotted bowtieantenna, we used HFSS, a full-wave EMsolver based on finite element method (FEM). Fig. 2 shows the frequency response of the computed return loss (S11) for the proposed antenna. The slotted bowtie antenna operates between 1 THz to 15 THz and gives three resonant frequencies (fr) at 7.1 THz, 11.1 THz and 13.1 THz at their respective frequencies band (FB)in Table 2.The plot shows return loss value of S11 = -30.4978 dB at resonating frequency 7.1 THz, S11 = -18.0104 dB at resonating frequency 11.1 THz, and S11 = -22.0171 dB at resonating frequency 13.1 THz. The antenna provides the impedance bandwidth of 2.8823 THz at 7.1 THz, 1.5868 THz at 11.1 THz and 1.7173 THz at 13.1 THz. The bandwidth (BW) was reduced due to losses. The deviation of the computed bandwidth for slotted bowtie antenna with respect to the simulated in arc truncated patch antenna is caused by parasitic properties of the structure [23]. Fig. 3 shows that the VSWR of the antenna remains less than 2 within the operating frequency band of the antenna.

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Fig.4 depicts the simulated real and imaginary part ofthe input impedance (Zin) of the slotted bowtie antenna madeof graphene strips. Impedance plot of the antenna confirms the resonance of a large band in the antenna structure. It can also be observed that one can obtain afrequency reconfigurable antenna by changing the chemicalpotential of the graphene based triangular patchantenna. The chemical penitential of agraphene patch can be changed by a gate voltage acting on theantenna or by chemical or electronic doping [24]. Fig. 5 shows axial ratio (AR) graph, but which value can be considered to be axial ratio of antenna to find the polarization of the proposed antenna in this paper. It enables the estimation of the radiation efficiency 𝜂𝑟𝑎𝑑 = Prad /Pacc of the slotted bowtie antenna, where Prad is the radiated power and Pacc is the accepted power at the antenna portas shown in Fig.6 and Fig. 7. Table 3 is shown different values of radiated power and accepted power at resonating frequencies. The total radiated power Prad is then found integrating for all directions. For this limit, states a close form expression obtained approximating the radiation pattern to the one of aHertzian dipole: −𝛾𝐿

−𝛾𝐿

8𝜋𝜂0 |𝐼𝑜 |2 √𝜀𝑟1 + √𝜀𝑟2 (1 − 𝑒 2 ) (1 − 𝛤𝐸 𝑒 2 ) Prad = . . (1 − 𝛤𝐸 𝑒 −𝛾𝐿 ) 3𝜆2 |𝛾|2 2 where𝜂𝑜 and λ are the free space impedance and wavelength respectively, and I o is the current as defined in [25]. AboutPacc , it is easily determined asPacc = Vin Iin , where the input voltage and current Vin and Iin can be computed since all the circuit parameters are known. Similarly, the total efficiency is given by𝜂𝑡𝑜𝑡 = Prad /Pav , where Pav is the source available power.

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One of the most significant features of an antenna is its radiation efficiency. As mentioned earlier in literature, due to nanomaterial with tunable frequency, the radiation efficiency of antennas made with graphene is expected to be better than the radiation efficiency of metallic antennas at a certain high frequency. The proposed antenna as a function of frequency at their respective resonating frequencies is shown in Fig.8. As mentioned in theTable 4, the use of graphene as patch material as well as lumped port material gives frequencies of resonance with 3D polar plotsmaximum Gain of 17.598 dB at 11.1 THz.The development of design approach for short range UWB antenna to transfer data up to a 10-meter distance earlier stated that the antenna needs a gain of more than 10 dB. This can be solved by making of the slotted bowtie antenna with graphene material, that will increase the directivity is declared in Table 4. Two other things of importance are that the efficiency stays nearly at 70% and the return loss stays at 10 dB this is a reflection of just 1 milliwatt out of 1 watt.The 3D E-field radiation patterns for slotted bowtie terahertz antenna using graphene as nanomaterial is detailed values in Table 4. Fig. 9 shows far-field radiation patterns of the proposed bowtie graphene-based patch antenna and it is clear from the simulated radiation pattern that gains are in the broadside direction all values of theta and (ϕ = 0°, 90°), at their respective resonating frequencies which is the direction of maximum radiation. Table 5 shows the comparision of the proposed slotted bowtie patch antenna with the other graphene patch antennas. It can be observed that the proposed antenna provides the highly directive which is much higer than other latest antenna structures.

4. Conclusions

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In this paper, one simple configuration used to obtain ultra wide-band and highly directive features whichshow significant improvement in graphene based slotted bowtie antenna. The FEM based HFSS full package software is engaged in simulating the antenna structure to obtain the S-parameter, VSWR, axial ratio, antenna impedance magnitude, radiated power, accepted power, radiation efficiency, the 3D radiation pattern, E-field distribution radiation, the 2D far-field gain and directivity. The 2D far-field directivity provides information about the radiation direction of the antenna. The best results concerning the highly directive with sufficient bandwidth are reached by the graphene based slotted bowtie antenna while the Vivaldi antenna exhibits the medium bandwidth followed by the spiral antenna which exhibits the smallest bandwidth among all. The 3D polar gain is 17.598 dB, the peak realized gain is 17.529 dB at 11.1 THz and the directivity is increased by almost 13 dB at 11.1 THz as compare with bow-tie antenna resonate at 7.1THz. The proposed antenna in this paper achieved fractional impedance bandwidth of 40.595% THz at 7.1 THz, 14.425% at 11.1 THz and 13.21% at 13.1 THz.

Conflict of Interests

Acknowledgements

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The authors declare that there is no conflict of interests regarding the publication of this paper.

References

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This work is supported by Department of Electronics and Communication Engineering of SantLongowal Institute of Engineering and Technology, Longowal, Punjab, by providing excellent lab facilities (High Frequency structural Simulator Software).

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[1] Chu, L. J. "Physical limitations of omni-directional antennas". Journal Applied Physics 19: 1163–1175 December 1948. [2] Bala, R; Marwaha, A. Investigation of graphene based miniaturized terahertz antenna for novel substrate materials. Engineering Science and Technology, an International Journal. 2015, 19(1), 531–537. [3] Bala, R; Marwaha, A.; Marwaha, S. Graphene antenna design for terahertz regime with exact formulation of surface conductivity. Journal of Nanoelectronics and Optoelectronics, 2016, 11(4), 459-464. [4] Dragoman, D., and Dragoman, M., Terahertz Fields and Applications, Progress in Quan. Electron, 2004, 26(1), pp.1-66. [5] Bala, R; Marwaha, A.; Marwaha, S. Performance enhancement of patch antenna in terahertz region using graphene. Current Nanoscience, 2016, 12(2), 237-243. [6] Bala, R; Marwaha, A. Analysis of graphene based triangular nano patch antenna using photonic crystal as substrate for wireless applications, Proceedings of IEEE Conference RAECS UIET Panjab University Chandigarh, India. 21-22nd December 2015. [7] Geim, A.; Novoselov, K.S. The rise of graphene. Nature Materials, 2007, 6, 183–191.

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[8] Novoselov, K.S.; A., Geim, A.K.; Morozov, S.; Jiang, D.; Katsnelson, M.; Grigorieva, I.; Dubonos, S.; Firsov, A. Two-dimensional gas of massless Dirac fermions in graphene. Nature, 2005, 438,197-200. [9] Llatser, I.; Kremers, C.; Cabellos - Aparicio, A.; Jornet, J. M.; Alarcon, E.; Chigrin, D. N. Graphene-based nanopatch antenna for terahertz radiation. Photonics and Nanostructures- Fund. and App., 2012, 10(4), 353- 358. [10] Bala, R; Marwaha, A.; Marwaha, S.; Singh R.Wearable graphene based curved patch antenna for medical telemetry applications. Applied Computational Electromagnetics Society Journal, 2016, 31(5), 543-550. [11] Pitra, K., and RAIDA, Z., (2011), ―Planar Millimeter-wave Antennas: A Comparative Study, Radioengineering, 20(1), pp. 263. [12] Bala, R; Marwaha, A.; Marwaha, S. Comparative analysis of zigzag and armchair structures for graphene patch antenna in THz band. Journal of Materials Science: Materials in Electronics. 2016, 27(5), 5064-5069. [13] Neto, A.H. C.; Guinea, F.; Peres, N. M. R.; Novoselov, K. S.; Geim, A. K. The electronic properties of graphene. Rev. Mod. Phys., 2009, 81(1), 109–162. [14] Hanson, G. W. Dyadic green’s functions and guided surface waves for a surface conductivity model of graphene. J. Applied Physics, 2008, 103 (6), 064302. [15] Bala, R. and Marwaha, A. 2014. Graphene based multiband triangular patchantenna for portable wireless applications. In Proceeding of IEEEConference Indian Antenna Week, National Institute of Technical TeachersTraining and Research Chandigarh, India. May 26-30. [16] Horng, J.; Fan Chen, C.; Geng, B.; Girit, C.; Zhang, Y.; Hao, Z.; Zettl, A.; Michael Crommie, F.; Ron Shen, Y.; Wang, F. Drude conductivity of dirac fermions in graphene. Phys. Rev. B 83, Condensed Matter and Materials, April 15, 2011, 16511. [17] Bala, R. and Marwaha, A. 2015. Performance analysis of graphene based nano patch antenna for various substrate materials in THz regime. In Proceedings of International Conference on Electrical and Electronics Engineering, Pattaya, Bangkok, Thailand. pp. 324-330. July11-12. [18] Bala, R; Marwaha, A.; Marwaha, S. Mathematical formulation of surface conductivity for graphene material. Journal of Engineering Science and Technology (JESTEC), School of Engineering, Taylor’s University, 2017, 12(6), 1677-1684. [19] James, J. R. and Hall, P.S. 1989. Handbook of Microstrip Antennas, Peter Peregrinus. ISBN 0-86341-150-9, London. [20] Balanis, C.A.; Antenna Theory Analysis and Design. John-Wiley and Sons Publications, 2nd Edition, 1997, ISBN No. 978-81-265-1393-2. [21] Rai, J., Dang, A., Malhotra, N. and Marwaha, A. 2014. Optimization of feed point location of low profile triangular patch antenna. IJECCE. 5(2): 285-288. [22] J.S. Dahele and K.F. Lee, "On the resonant frequencies ofthe triangular patch antenna," IEEE Trans. Antennas Propagat., vol. AP-35, no. I, pp. 100-101, 1987. [23] GauravBansal, AnupmaMarwaha, Amanpreet Singh, RajniBala, Sanjay Marwaha, " Graphene based Wideband Arc Truncated Terahertz Antenna for Wireless Communication", Current Nanoscience, Bentham Science, vol. 14, ISSN: 1875-6786 (Online), ISSN: 1573-4137 (Print), pp.1-8, 2018. [24] Bala, R; Marwaha, A. Development of computational model for tunable characteristics of graphene based triangular patch antenna in THz regime. Journal of Computational Electronics, 2016, 15(1), 222–227. [25] M Tamagnone, J Perruisseau-Carrier, 2014. Predicting input impedance and efficiency of graphene reconfigurable dipoles using a simple circuit model.IEEE Antennas and Wireless Propagation Letters 13, 313-316. [26] Anand, S.; Sriramkumar, D.; Jang Wu, R.; Chavali, M. Graphene nanoribbon based terahertz antenna on polyimide substrate. Optik, Science Direct, 2014, 125, 2014, 5546–5549. [27] Bala, R; Marwaha, A. Characterization of graphene for performance enhancement of patch antenna in THz region. Optik-International Journal for Light and Electron Optics, 2016, 127(4), 2089-2093. [28] Thampy, A. S., M. S. Darak, and S. K. Dhamodharan, “Analysis of graphene based opticallytransparent patch antenna for terahertz communications,”Physica E: Low-dimensional Systems and Nanostructures, Vol. 66, 67– 73, 2015. [29] Mohammed TaihGatte, Ping Jack Soh1, Hasliza A. Rahim, R. Badlishah Ahmad, and Mohamed Fareq Abdul Malek, “The Performance Improvement of THz Antenna via Modeling and Characterization of Doped Graphene”,Progress In Electromagnetics Research M, Vol. 49, 21–31, 2016.

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Figure captions

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(a)

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(b) Fig. 1. Graphene based slotted bowtie patch antenna

Fig. 2. Return loss curve, for slotted bowtie antenna at h=3 μm

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Fig.3. VSWR curves, for slotted bowtie antenna at h=3 μm

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Fig. 4. Z parameters curves, for slotted bowtie antenna at h=3 μm

Fig.5. Axial ratio for slotted bowtie antenna

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Fig.6. Radiated power for slotted bowtie antenna

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Fig.7. Accepted power for slotted bowtie antenna

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Fig.8. Radiation efficiency (in %) versus frequency in operating range 1.00 – 15.00 THz for slotted bowtie antenna

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(a) 2D radiation pattern of Gain at resonating frequency 7.1 THz

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(b) 2D radiation pattern of Gain at resonating frequency 11.1 THz

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(c) 2D radiation pattern of Gain at resonating frequency 13.1 THz Fig.9. 2D far field radiation pattern slotted bowtie terahertz antenna(ϕ = 0° with purple color) and (ϕ = 90° with red color)

Table Table 1 Dimensions of graphene based slotted bowtie terahertz patch antenna. Parameter Substrate length and width (Ls × Ws)

Value 40 μm × 40 μm

Substrate thickness (h)

3 μm

Port gap width

4.0 0.22 μm × 7.89 μm 1 nm 0.44μm

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Table 2 The simulated parameters of graphene based slotted bowtie terahertz patch antenna. fr S11 FB BW FBW VSWR (THz) (dB) (THz) (THz) (%) 7.1 -30.4978 8.8436 2.8823 40.595 1.0594 5.9613 11.1 -18.0104 11.75611.5868 14.425 1.2877 10.1693 13.056 -22.0171 14.07101.7173 13.21 1.1722 12.3537

8.76 μm

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Arm length of bowtie antenna (LA)

1.5002 2.7546 3.2560

Pacc (dBm) 29.9964 29.9308 29.9726

𝜂𝑟𝑎𝑑 (%) 71 71 43

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Prad (dBm) 29.4033 29.3353 27.2273

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Zin (Ohms) 52.49 63.19 55.91

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Table 3 The computed parameters of the slotted bowtie terahertz patch antenna with graphene. fr (THz) 7.1 11.1 13.056

Table 4 The parameters of graphene based slotted bowtie terahertz antenna. Gain (dB)

Directivity (dB)

7.1 11.1 13.056

4.9131 17.598 11.642

5.5062 18.194 14.388

Realized Gain (dB) 4.9095 17.529 11.651

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fr (THz)

Radiated electric field 22.691 35.311 29.396

fr (THz)

t (nm)

Gain (dB)

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Table 5 Comparison of the proposed graphene antenna with previously reported antennas in Literature.

2.86 0.75 13

10

6 5.09 5.3039

Directi vity (dB) 5.71 5.3216

[24]

2.5

3.35

6.59

6.91

0.8 5

-

0 7.895

-

7.4022

-

Ref.

[14] [26] [27]

[28] [12]

Antenna Struture

Yagi antenna Rectangular patch Graphene square patch Antenna Equilateral triangular graphene patch antenna Strip dipole Zig Zag Graphen e patch antenna armch with air structu

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Substrate dielectric constant (Silicon dioxide SiO2 ,εr ) Inner width and outer width of bowtie antenna (WI × Wo) Bowtie Patch height (∆)

[29] [23]

1.3 1.494 18.00 11.1

10

7.20 7.21 7.1011

7.46 7.43 7.2781

1

17.598

18.194

Slotted Bowtie antenna

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Pro pose d

re Patch 2 Elliptical patch Patch 3 Arc Truncated THz antenna