A single layer wideband Vivaldi antenna with a novel feed structure

(1)

A single layer wideband Vivaldi antenna with a novel feed structure

Item Type Article

Authors Ghaffar, Farhan A.;Roy, Noben K.;Shamim, Atif

Citation Ghaffar, F. A., Roy, N. K., & Shamim, A. (2023). A single layer wideband Vivaldi antenna with a novel feed structure.

IET Microwaves, Antennas & Propagation. Portico. https://

doi.org/10.1049/mia2.12366 Eprint version Publisher's Version/PDF

DOI 10.1049/mia2.12366

Publisher Institution of Engineering and Technology (IET) Journal IET Microwaves, Antennas & Propagation

Rights Archived with thanks to IET Microwaves, Antennas & Propagation under a Creative Commons license, details at: http://

creativecommons.org/licenses/by-nc-nd/4.0/

Download date 2024-01-17 20:59:07

Item License http://creativecommons.org/licenses/by-nc-nd/4.0/

Link to Item http://hdl.handle.net/10754/691301

(2)

Received: 6 November 2022

-

Revised: 9 April 2023

-

Accepted: 18 April 2023

- IET Microwaves, Antennas & Propagation

DOI: 10.1049/mia2.12366

O R I G I N A L R E S E A R C H

A single layer wideband Vivaldi antenna with a novel feed structure

Farhan A. Ghaffar

¹

| Noben K. Roy

¹

| Atif Shamim

²

1Department of Electrical Engineering, Lakehead University, Barrie, ON, Canada

2Electrical Engineering Program, CEMSE Division, KAUST, Thuwal, Saudi Arabia

Correspondence

Farhan A. Ghaffar, Office F‐118F, One Georgian Drive, Georgian College, Barrie, ON, L4M 3X9, Canada.

Email:[email protected]

Abstract

An increase of 7 GHz in the industrial, scientific and medical ISM band around 60 GHz has opened it up for many modern wireless applications such as 5G. This means that new component designs that can cater for this large bandwidth are the need of the hour. The design of a large bandwidth, completely planar and high gain novel Vivaldi antenna is presented. Being a travelling wave antenna and implemented using single metal layer make it an excellent candidate for not only Printed Circuit Board based applications but also the lossy Complementary Metal Oxide Semiconductor technology. For the first time, the feed of the antenna is integrated on the same conductor layer as the antenna itself. Using this design technique the problem of thin gap between the metal layers has been mitigated. The final measured results show that the antenna goes above and beyond ISM band with excellent matching performance from 55 to 84 GHz. A high gain of 7 dBi is maintained over a bandwidth of 57–75 GHz with a radiation efficiency of almost 80%. The results show that the design is quite suitable for integration in a millimetre‐wave transceiver system that can support high data rate applications.

K E Y W O R D S

ultra wideband antennas, Vivaldi antennas

1 | INTRODUCTION

Millimetre‐wave wireless communication is being studied extensively to be used in various fixed wireless applications and technologies. Among them is the ever‐growing 5G communication that is vastly considered as the future of wireless applications. This has resulted in a recent amendment of the 802.11 Institute of Electrical and Electronics Engineers (IEEE) standard for the 60 GHz unlicensed band communication [1]. Pre- viously, this frequency band expanded from 57 to 64 GHz and was allocated under industrial, scientific and medical standards.

With this new modification, another 7 GHz have been added to this frequency spectrum resulting in an available bandwidth of 14 GHz (57–71 GHz) within this unlicensed band. As a result, Radio Frequency (RF) designers are looking for wireless solu- tions that can exploit this new change in the said IEEE standard [2]. The trend has seen its effect in the field of antenna engineering [3–5].

A popular candidate that can provide the desired impedance and radiation performance within this band is

Vivaldi or Tapered Slot Antenna (TSA) [6–8]. The reason being the ability of such an antenna to provide large impedance bandwidth while maintaining excellent gain and efficiency performance. Conventionally, this class of antenna has been implemented using technologies that can support and provide a multilayer metal stack up. This includes Printed Circuit Board (PCB), Low Temperature Cofired Ceramic and even Complementary Metal Oxide Semiconductor (CMOS) [6, 9, 10]. However, in the CMOS technology the design presented is a single layered one. The rationale for this is the extremely narrow gaps present between the consecutive metal layers of a CMOS stack up. Because of which it is not possible to excite the proper travelling mode for this type of antenna. Thus, a certain minimum thickness of the substrate is required to achieve the adequate antenna performance from such a design.

To resolve the problem, a fully planar Vivaldi antenna is presented in this work on Rogers RO3003 substrate. In addition, the authors have also studied the same design on a CMOS stack up [6]; however the results reported show poor

This is an open access article under the terms of theCreative Commons Attribution‐NonCommercial‐NoDerivsLicense, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.

IET Microw. Antennas Propag.2023;1–7. wileyonlinelibrary.com/journal/mia2

-

¹

(3)

bandwidth and gain performance. The rationale for using a PCB based substrate is to provide the proof‐of‐concept and the ease and availability of the fabrication process. A coplanar waveguide (CPW) feed line to an aperture/slot transition is employed to excite the antenna. Initially, the transition is simulated in a back‐to‐back configuration, eventually integrating it with a planar Vivaldi antenna structure. The design under study is thoroughly characterised for its impedance and radiation characteristics including efficiency. This is a merit at such high frequencies for probe‐fed antennas, as many times it is not possible to characterise the antenna structures resulting in alternate inexact methods [11, 12]. The final antenna shows an impedance bandwidth of 29 GHz (55–84 GHz) with a maximum gain of 7 dBi. An excellent and stable gain performance over a large bandwidth is achieved with measured radiation efficiencies of almost 80%.

2 | DESIGN CHALLENGE

The motive behind the proposal of a planar Vivaldi/slot antenna is to provide a suitable solution to on‐chip applications.

Although this design is not only focussed on silicon based substrate but its efficacy can be observed when studied in context of such antenna designs. One of the main challenge with on‐chip antennas is their poor efficiency and low gain values [13]. This has been a keen topic of interest for antenna designers in the last few decades. One technique to mitigate the lossy nature of silicon is to reduce its impact on the antenna performance. This can be accomplished by the use of travelling wave antennas such as TSA. However, when it comes to Vivaldi antenna, the requirement of two metal layers makes it quite complicated. The reason is the available metal stack ups in CMOS technologies. The current technologies usually consist of a 300–500 μm silicon substrate with oxide layers of 15–20 μm wide on the top. The metal layers are embedded inside the oxide layer and are spaced with a distance of 1–2 μm.

This space between metal layers can be even smaller than a few microns. This stack up entails within itself the challenge of implementing a Vivaldi antenna. To illustrate this effect, the authors simulated two Vivaldi antennas: 1) antipodal antenna design which needs two conductor layers for each antenna arm (Figure 1a) and 2) single layer antenna design which has both arms on one conductor layer but needs a bottom conductor layer for the microstrip feed line (Figure1b). For the antipodal design, the gap between its two arms is varied from 0.2 to 10 μm with a little effect on its radiation characteristics. The radiation pattern remained consistently poor depicting no travelling wave phenomenon and is shown in Figure 2a. The two extremes used in these simulations are the common gaps that can be seen between two consecutive metal layers in a CMOS stack up. To provide a proof of concept and to verify that a thicker gap is needed the authors simulated the two arms of the antipodal design with a gap of more than 100 μm. It is noteworthy that the radiation characteristics of an identifiable Vivaldi antenna can be seen (Figure 2b). The gain of the

antennas in Figure 2a and bare −8 dBi and –1 dBi, respectively. This problem of a minimum finite gap requirement between the two arms of the Vivaldi antenna is not pertinent to CMOS stack up. To confirm this fact, the authors performed the same simulations on a conventional RO3003 (εr ~ 3, tanδ = 0.001) substrate while varying the thicknesses in the same manner. These simulations seconded the results seen in Figure 2, with an efficient gain of 8 dBi when the substrate thickness is in acceptable range (i.e. 500 μm). Furthermore, when the Vivaldi antenna of Figure1bis simulated with a gap of few microns (0.2–10 μm) between the feed line and the slop, the same conclusion is confirmed that the antenna has poor radiation efficiency (depicted in Figure 2c). If the gap is increased to few 100 microns, reasonable radiation performance of the antenna can be achieved similar to Figure 2b.

This means that a single layer or planar Vivaldi antenna is needed in applications where a single metal layer is either available or if the gap between metal layers is infinitely small.

F I G U R E 1 Vivaldi antenna (a) antipodal design (b) single layer design.

F I G U R E 2 Simulated radiation patterns of Vivaldi antennas (a) antipodal design with a gap of 0.2–10 μm, (b) antipodal design with a gap of>100 μm, and (c) single layer design with a gap of 0.2–10 μm.

2

-

^GHAFFAR^{ET AL}^.

17518733, 0, Downloaded from https://ietresearch.onlinelibrary.wiley.com/doi/10.1049/mia2.12366 by Cochrane Saudi Arabia, Wiley Online Library on [30/04/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

(4)

3 | SINGLE LAYER FEED TRANSITION

As explained in the last section, that the conventional Vivaldi antenna designs have their limitations when the substrate thickness values goes to few microns. To cater for this downside, a transition is needed that can feed the slot of the Vivaldi antenna from the same layer where the metal arms of the antenna are implemented. Thus, the authors propose the use of a CPW to slot transition on RO3003 substrate that is reported in ref. [14], shown in Figure 3.

The transition consists of a CPW feed line that excites a slot that makes a right angle with the feed line. Notably, the length of the CPW line is beyond the point where the slot starts. This extension is kept at approximately quarter‐

wavelength. The other edge of the feed line is left open circuited which mimics a short circuit impedance (quarter wave transformation) near the starting point of the slot. This allows for maximum coupling of RF signal from the CPW feed into the slot. In order to improve the bandwidth and the matching of the transition, a slot matching stub is placed at the back of the point where short circuit is established. The length of the matching stub is optimised using a series of simulations to make the transition work at and around 60 GHz. The impedance of the CPW line is 50 Ω, while the width and the length of the slot can be optimised for best possible RF response. The simulated feed transition provides an acceptable reflection coefficient from 54 to 71 GHz with an insertion loss of ~1 dB. Here, the feed transition can be further optimised to improve the impedance bandwidth. However, since the integration of the transition with the antenna will require another set of optimisation, the authors preferred it to be completed in one final step, which is the antenna design itself.

4 | ANTENNA DESIGN

The back‐to‐back feed transition discussed in the last section is to be integrated with a Vivaldi antenna to realise the single layer design. For this purpose, one half of the transition is combined with the antenna structure as shown in Figure 4. A 50 Ω CPW line is used to feed the antenna. The antenna is implemented on RO3003 substrate with a thickness of 500 μm.

The rationale for using this substrate is its lower dielectric

constant and RF loss at 60 GHz, as claimed by the manufac- turer. Initially, the antenna is designed to have an opening width,w_a=5 mm with an equal length of the antenna,l_a.

The rationale for using 5 mm as the value forw_ais the free space wavelength,λ₀at 60 GHz. Typically, this class of antenna is designed to have dimensions close toλ₀. However, since the antenna is implemented on a substrate, its dielectric constant would have an effect on the equivalent dimensions of the antenna. Using Ansys High Frequency Structure Simulator, the optimised value of w_a is determined to be 3 mm where the antenna shows reasonable performance in terms of its impedance and radiation. It is worth mentioning here that the length,l_a, is important to achieve the right impedance as well as to gain performance. For instance, increasing the magnitude of this parameter causes a downward shift in the impedance bandwidth of the antenna and vice versa. The simulations show that a good value forl_ais 2.3 mm and it is thus selected with the centre of the ellipse represented byl_candh_c. Two ellipse of equal dimensions but mirror images of each other are used to realise the antenna structure. Once the antenna dimensions give acceptable impedance and radiation performance, the next step is to study the effect of the slot width, w_s. In fact, this is the most sensitive parameter and requires special care while integrating the antenna to the feed transition.

The parametric study ofw_sshows that if its value is reduced to 0.2 mm (~0.1 mm less), than the antenna would exhibit a reduction of 35% in its bandwidth. This is a major inference from these simulations. During fabrication, special attention should be given to this parameter. A final optimised value for w_sis determined to be around 0.33 mm that allows the antenna to radiate well for the entire bandwidth while providing good gain performance. In addition, it is important to bring it to the attention of the readers that the width of the slot in the case of the antenna is not uniform as opposed to the feed transition. It means that the slot matching stub at the back of the antenna plays an important role to improve the impedance matching and at the same provide a better front‐to‐back ratio.

However, this step of optimisation is much simpler now due to the study explained in the last section. The final antenna model

F I G U R E 3 Back‐to‐back coplanar waveguide (CPW) to slot transition.

F I G U R E 4 Fully planar Vivaldi antenna with coplanar waveguide (CPW) to slot transition (units: mm).

(5)

(Figure4, with detailed dimensions) demonstrates a maximum gain of 8 dBi, which is maintained well from 55 to 73 GHz.

The impedance bandwidth of the antenna is observed to be 25 GHz (48–73 GHz). The simulated gain does not go below 6 dBi at any point in the entire bandwidth proving that the antenna performs in an efficient manner throughout the frequency band. The impedance performance of the antenna is to be compared with the measured data in the next section and is therefore not presented here to avoid repetition. The normalised radiation patterns of the antenna at 50 GHz, 60 and 70 GHz are shown in Figure 5 (YZ: H‐Plane and XY: E‐

Plane). A directional radiation performance can be observed from the results which is expected from such an end‐fire antenna design.

As a proof‐of‐concept and due to the lack of CMOS fabrication facility, the antenna is designed on a PCB based substrate. However, in simulations the results on the CMOS process are also reported herein. The same antenna structure when simulated on a silicon substrate (300 μm thick with a 10 μm thick oxide layer) provides a lower gain and efficiency which is expected. A maximum gain of −2 dBi is obtained from the antenna due to the low resistivity of the substrate (10 Ω.cm). The gain of this design can be improved by using a thinner silicon substrate or by using a high‐resistivity substrate [13]. In any case when simulated on CMOS, the value of the antenna gain is in acceptable range for short range wireless communications (~1–2 m) such as WPAN (Wireless Personal Area Network). The radiation pattern of the antenna on the silicon substrate is quite similar to the ones shown in Figure5 and its bandwidth is also comparable to the antenna designed on RO3003. Hence, a conclusion can be drawn that the design concept can be easily translated to CMOS technology except with a reduced radiation efficiency.

5 | MEASURED RESULTS

The realisation of the proposed antenna design even on a PCB is a challenge due to its small feature size. The authors used LPKF's ProtoLaser U3 System that can etch out a line width and spacing of 50 μm with credible effectiveness. The fabri- cated prototype antenna from a microscope camera is shown in Figure 6 with the measurement environment: Orbit's MicroLab antenna chamber. The equipment allows for the probe‐fed measurements of the antenna which is quite handy for the millimeter wave antenna designs. The antenna is tested using a GSG (ground signal ground) infinity probe (pitch:

150 μm) for both impedance and radiation characteristics. The impedance measurements are done with the help of a Cascade Probe Station in the presence of an absorber substrate underneath as well as inside the chamber to provide reliable results. The use of the absorber substrate is essential in this case since the antenna does not have a ground plane at the bottom and its performance can be severely affected by the metal chuck that is present in all the probe stations.

The impedance results of the antenna are shown in Figure7.

A measured bandwidth of 29 GHz (55–84 GHz) can be observed with some deviation from the simulated data. These results entail an impedance bandwidth of 42% around the centre frequency. There can be a number of reasons for the deviation

F I G U R E 5 Simulated radiation pattern of the antenna (a) 50 GHz, (b) 60 GHz and (c) 70 GHz (Solid line: E‐plane, Dashed line: H‐Plane).

F I G U R E 6 Antenna prototype and anechoic chamber set up.

F I G U R E 7 Simulated and measured impedance performance.

4

-

^GHAFFAR^{ET AL}^.

(6)

from simulations. The first and foremost being the dielectric properties and thickness of the substrate. Rogers does not provide the exact dielectric constant of 3003 substrate above 50 GHz. There is bound to be some deviation from a value of 3 at higher frequencies. To estimate a better match between the simulated and measured reflection coefficient, the dielectric constant of the substrate is varied in the range of 10%–20%.

With the latter case, the impedance bandwidth of the antenna moves up in the frequency spectrum by 4 GHz. Similarly, a 100 μm of change in the substrate thickness can allow for the impedance bandwidth to shift by ~1 GHz. This change in the substrate thickness is quite possible due to fabrication discrep- ancies. Finally, the presence of an absorber underneath the antenna can also result in some deviation between the two results.

With the changes in the dielectric properties of the material and its thickness, the post‐measurement simulations show a reasonable match with the measured results, shown in Figure7.

However, it is important to impress upon the readers that these simulations are based on a conjecture due to the inability to exactly characterise the antenna substrate and the unknown properties of the absorber. Nonetheless, a reasonable match can be observed between the reflection coefficients (Figure7) using the post‐measurement simulation results that are reported in this work.

Finally, the antenna is characterised for its radiation, gain and efficiency performance in the anechoic chamber. A comparison between the normalised E‐and H‐plane radiation patterns at 60 GHz is presented in Figure 8. An excellent match can be observed between the two results. It is important to mention it here that the antenna chamber can only measure within a range of�150° in one of the planes, which is the E‐plane in this case.

This can be regarded as the blind spot in the chamber due to the presence of the probe setup. As a result, the E‐plane curve in Figure8is only plotted within�150°. Other than this exception, the correlation between the two sets of data is quite optimal. The measured gain and radiation efficiency of the antenna versus the simulated values are presented in Figures9and10, respectively.

The simulated and measured gain curves follow each other closely with a difference of around 1 dB between them. This discrepancy can be attributed to the substrate losses which are

unknown at higher frequencies. Despite this, the correlation between the two gain curves is within the acceptable range. The same trend can be observed in the simulated and measured values of the antenna's efficiency shown in Figure10. In simulations, the radiation efficiency is generally around 95% with a maximum variation of+1% across the frequency band whereas the measured curve hovers around 80%. All these metrics show that the antenna performance is well reproduced in the measurements validating the design proof‐of‐concept.

6 | COMPARISON WITH THE STATE‐

OF‐THE‐ART

A brief comparison of the design proposed in this work with the literature on Vivaldi antenna is summarised in Table 1.

There are not many designs that can cover the frequency range of 55–84 GHz. Moreover, only one design is based on a single layer antenna structure [15] for CMOS applications; however, this design fails to validate the data with the help of an actual

F I G U R E 8 Simulated and measured radiation pattern of the antenna at 60 GHz.

F I G U R E 9 Simulated and measured maximum gain of the antenna versus frequency.

F I G U R E 1 0 Simulated and measured radiation efficiency of the antenna versus frequency.

(7)

prototype. All other designs reported herewith need more than one metal layer for antenna implementation. If the focus is limited to 60 GHz, then most of the papers rely on simulated model without any impedance or radiation characterisation [15–18]. The antennas in refs. [9, 19] are proposed for 60 GHz and validated with the measured results. However, both these designs rely on multiple metallic layers with a modest gain value shown by [9]. Within sub‐millimetre‐wave range, a few examples of PCB based antennas are also included in the table for the benefit of the readers [20–22]. To summarise, there are limited vivaldi antenna designs operating around 60 GHz with no single layered vivaldi antenna designs that can cover the frequency range reported in this paper while providing stable gain performance.

7 | CONCLUSION

The paper presents the design of a completely planar Vivaldi antenna on Rogers RO3003 substrate. The simulated results show that the design can easily cover the bandwidth requirements of IEEE 802.11 standard (57–71 GHz). The antenna provides excellent gain and efficiency performance that has been validated by both simulations and measurements.

Although a PCB based substrate has been used to provide the proof‐of‐concept, the authors deem this design to be aptly suitable for on‐chip integration on CMOS technology.

A UT H O R C O N T R I B U T I O N S

Farhan A. Ghaffar: Conceptualisation, Formal analysis, Investigation, Methodology, Software, Validation, Writing – original draft. Noben K. Roy: Data curation, Software.

Atif Shamim: Supervision, Writing – review & editing.

C O N F L I C T O F I N T E R E S T S TA T E M E N T There are no conflict of interest to disclose.

P E R M I S S I O N T O R E P RO D U C E M A T E R I A L S F R O M O TH E R S O U R C E S

None.

DA TA AVA I L A B I L I T Y S TA T E M E N T Data available on request from the authors.

O R CI D

Farhan A. Ghaffar https://orcid.org/0000-0002-4996-6290

R E F E R E N C E S

1. IEEE standard for information technology‐telecommunications and information exchange between systems‐local and metropolitan area networks‐‐specific requirements‐Part 11: wireless LAN medium access control (MAC) and physical layer (PHY) specifications amendment 3:

enhancements for very high throughput in the 60 GHz band. IEEE Stand.

802.11ad‐2012, 1–628 (2012)

2. Öjefors, E., et al.: A 57‐71 GHz beamforming SiGe transceiver for 802.11 ad‐based fixed wireless access. In: IEEE Radio Frequency Inte- grated Circuits Symposium (RFIC) (2018)

3. Zhu, Q., et al.: Substrate‐integrated‐waveguide‐fed array antenna covering 57–71 GHz band for 5G applications. IEEE Trans. Antenn.

Propag. 65(12), 6298–6306 (2017). https://doi.org/10.1109/tap.2017.

2723080

4. Al‐Alem, Y., Kishk, A.A.: Low‐cost high‐gain superstrate antenna array for 5G applications. IEEE Antenn. Wireless Propag. Lett. 19(11), 1920–1923 (2020). https://doi.org/10.1109/lawp.2020.2974455

5. Chen, Q., et al.: Efficient leaky‐lens antenna at 60 GHz based on a substrate‐integrated‐holey metasurface. IEEE Trans. Antenn. Propag.

68(12), 7777–7784 (2020). https://doi.org/10.1109/tap.2020.2998865 6. Ghaffar, F.A., Roy, L., Shamim, A.: A wideband fully planar vivaldi an-

tenna for WPAN applications. In: 18th International Symposium on Antenna Technology & Applied Electromagnetics (ANTEM), pp. 1–3 (2018)

7. Wu, J., et al.: A printed UWB vivaldi antenna using stepped connection structure between slotline and tapered patches. IEEE Antenn. Wireless Propag. Lett. 13, 698–701 (2014). https://doi.org/10.1109/lawp.2014.

2314739

8. Mirbeik‐Sabzevari, A., et al.: W‐band micromachined antipodal vivaldi antenna using SIW and CPW structures. IEEE Trans. Antenn.

Propag. 66(11), 6352–6357 (2018). https://doi.org/10.1109/tap.2018.28 63098

9. Bisognin, A., et al.: PCB integration of a vivaldi antenna on IPD technology for 60‐GHz communications. IEEE Antenn. Wireless Propag. Lett. 13, 678–681 (2014). https://doi.org/10.1109/lawp.2014.

2314444

10. Brzezina, G., Roy, L., MacEachern, L.: Planar antennas in LTCC technology with transceiver integration capability for ultra‐wideband applications. IEEE Trans. Microw. Theor. Tech. 54(6), 2830–2839 (2006).

https://doi.org/10.1109/tmtt.2006.875448

11. Marin, J.G., et al.: High‐gain low‐profile chip‐fed resonant cavity antennas for millimeter‐wave bands. IEEE Antenn. Wireless Propag.

Lett. 18(11), 2394–2398 (2019). https://doi.org/10.1109/lawp.2019.29 26791

12. Moody, J., et al.: A Vivaldi antenna based W‐band MUTC photodiode driven radiator. In: IEEE International Topical Meeting on Microwave Photonics (MWP), pp. 217–220 (2016)

13. Cheema, H.M., Shamim, A.: The last barrier: on‐chip antennas. IEEE Microw. Mag. 14(1), 79–91 (2013). https://doi.org/10.1109/mmm.2012.

2226542

14. Ho, C., et al.: Experimental investigations of CPW‐slotline transitions for uniplanar microwave integrated circuits. In: IEEE MTT‐S International Microwave Symposium Digest, pp. 877–880 (1993)

15. Sultan, K.S., et al.: A 60‐GHz gain enhanced vivaldi antenna on‐chip. In:

IEEE International Symposium on Antennas and Propagation & USNC/

URSI National Radio Science Meeting, pp. 1821–1822 (2018)

16. Bahuguna, T., Sandhana Mahalingam, M., Pandeeswari, R.: Design of V‐

band balanced antipodal vivaldi antenna for 60 GHz point‐to‐point communication. In: TEQIP III Sponsored International Conference on Microwave Integrated Circuits, Photonics and Wireless Networks (IMICPW), pp. 345–347 (2019)

T A B L E 1 Comparison of state‐of‐the‐art vivaldi antennas.

Reference

Frequency [GHz]

Gain

[dBi] Layers Validation

[9] 56–67 4 Multi Measured

[15] 50–70 0.7 Single Simulated

[16] 40–75 11.5 Multi Simulated

[17] 57–64 8 Multi Simulated

[19] 55–65 15 Multi Measured

[20] 25–35 3.8 Multi Measured

[21] 24–40 6 Double Measured

[22] 5.3–40 11 Double Measured

This work 55–84 7 Single Measured

6

-

^GHAFFAR^{ET AL}^.

(8)

17. Hahnel, R., Benedix, W.‐S., Plettemeier, D.: Broadside radiating vivaldi antenna for the 60 GHz band. Int. Workshop Antenna Technol. (iWAT), 83–86 (2013)

18. Ghaffar, F.A., et al.: 60 GHz system‐on‐chip (SoC) with built‐in memory and an on‐chip antenna. In: The 8th European Conference on Antennas and Propagation (EuCAP 2014), The Hague, Netherlands, pp. 531–532 (2014)

19. Mohamed, I., Sebak, A.: A 60 GHz SIW‐based Vivaldi antenna with improved radiation patterns. IEEE Int. Symposium Antennas Propag.

(APSURSI), 805–806 (2016)

20. Fan, C., et al.: Millimeter‐wave pattern reconfigurable vivaldi antenna using tunable resistor based on graphene. IEEE Trans. Antenn.

Propag. 68(6), 4939–4943 (2020). https://doi.org/10.1109/tap.2019.29 52639

21. Puskely, J., et al.: High‐gain dielectric‐loaded vivaldi antenna for ka‐band applications. IEEE Antenn. Wireless Propag. Lett. 15, 2004–2007 (2016).

https://doi.org/10.1109/lawp.2016.2550658

22. Yin, Z., et al.: Miniaturized ultrawideband half‐mode vivaldi antenna based on mirror image theory. IEEE Antenn. Wireless Propag. Lett.

19(4), 695–699 (2020). https://doi.org/10.1109/lawp.2020.2977503

How to cite this article:Ghaffar, F.A., Roy, N.K., Shamim, A.: A single layer wideband Vivaldi antenna with a novel feed structure. IET Microw. Antennas Propag.

1–7 (2023).https://doi.org/10.1049/mia2.12366