A Novel SIW Leaky-Wave Antenna for Continuous Beam Scanning from Backward to Forward
Round 1
Reviewer 1 Report
Authors have presented and interesting work entitled “A Novel SIW Leaky Wave Antenna for Continuous Beam Scanning from Backward to Forward” where periodic leaky-wave array antenna in substrate integrated waveguide (SIW) technology is proposed for continuous beam scanning applications. The work is supported with results and discussion, having +/- 60 deg scanning with a high gain up to 16 dBi. Manuscript may be checked for typos and grammatical errors.
Author Response
Dear Reviewer,
Thank you very much for taking your time and considering our manuscript. We appreciate your valuable suggestions on our manuscript, which are very helpful to improve the overall quality of the manuscript. We have revised the manuscript based on your valuable comments, and would like to re-submit it for your consideration.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Authors in this research article have presented and investigated a substrate integrated waveguide-based leaky-wave antenna for usage in continuous beam scanning applications. The unit cell of the LWA consists of the longitude slot and the rectangular-shaped H-plane discontinuity and was proposed to suppress the open stopband. The open stopband suppression was performed using an impedance matching technique. A prototype of the proposed antenna was fabricated for use in experimental verification. The concept and idea of this work are interesting and the promising results have been introduced and experimentally validated. The advantages of the proposed work have been highlighted by providing a fair comparison with state-of-the-art. Although this work has been found attractive for the antenna and propagation society, authors are requested to carefully address the following comments to improve its quality prior to final recommendation.
1) Abstract section is short and it needs to be extended as below.
- a) Please briefly describe the design process of the proposed periodic leaky-wave array antenna based on the substrate integrated waveguide technology.
- b) Some of the antenna’s performance parameters such as its physical dimensions, operational bandwidth, average radiation efficiency are missing, please add them to this part.
- c) Please highlight the advantages of the proposed antenna.
- d) The practical applications of the antenna can be mentioned in this part as well.
2) Introduction section is not properly supported by enough references. For example, the first paragraph of this part is without any references. Below are some helpful suggestions which can improve this part.
“A New Design Approach of Low-Noise Stable Broadband Microwave Amplifier Using Hybrid Optimization Method”, IETE Journal of Research, 2020, Doi: 10.1080/03772063.2020.1787879.
“Scannable Leaky-Wave Antenna Based on Ferrite-Blade Waveguide Operated below the Cutoff Frequency” IEEE Transactions on Magnetics, 2021, Doi: 10.1109/TMAG.2021.3060683.
"MTM- and SIW-Inspired Bowtie Antenna Loaded with AMC for 5G mm-Wave Applications" International Journal of Antennas and Propagation, Volume 2021, Article ID 6658819, 7 pages https://doi.org/10.1155/2021/6658819.
“Backfire-to-endfire scanning capability of a balanced metamaterial structure based on slotted ferrite-filled waveguide”, Waves Random Complex Media. (2019) 1-15, Doi: 10.1080/17455030.2019.1654148.
D. Serghiou, M. Khalily, V. Singh, A. Araghi and R. Tafazolli, "Sub-6 GHz Dual-Band 8 × 8 MIMO Antenna for 5G Smartphones," in IEEE Antennas and Wireless Propagation Letters, vol. 19, no. 9, pp. 1546-1550, Sept. 2020.
“A novel monofilar-Archimedean metamaterial inspired leaky-wave antenna for scanning application for passive radar systems”, Microw Opt Technol Lett. 2018;60:2055–2060.
"New Compact Printed Leaky-Wave Antenna with Beam Steering", Microwave and Optical Technology Letters, Volume 58, Issue 1, January 2016, Pages: 215–217.
3) Fig.1 shows the proposed SIW LWA’s layout, please explain the working principle of the linear slots in the middle of the structure? Also, please describe the impacts of the SIW technique and its configuration of implementation? It is observed that the upper line and bottom line of SIW have different shapes, so please describe why? The effects of this layout on the antenna’s performance parameters can be interesting for readers.
4) In Fig. 2 authors have presented the ideal waveguide with longitude slot, and in Fig.3 the T-Network model for longitude slot is shown, please discuss the relation between this ideal waveguide and extracted T-network.
5) How the equivalent circuit for H-plane step, short waveguide section, and rectangular-shaped H-plane discontinuity exhibited in Fig.6 were extracted?
6) How authors have achieved the Π-network circuit equivalent for waveguide with rectangular shaped H-plane discontinuity? Please explain it.
7) If possible please add a higher image of the fabricated prototype of SIW LWA shown in Fig.19.
8) More examples of the impedance matching techniques can be mentioned in the introduction section.
"Impedance Bandwidth Improvement of a Planar Antenna Based on Metamaterial-Inspired T-Matching Network," IEEE Access, vol. 9, pp. 67916-67927, 2021.
"Improved Adaptive Impedance Matching for RF Front-End Systems of Wireless Transceivers", Scientific Reports, 10, 14065 (2020).
"Impedance Matching Network Based on Metasurface (2-D Metamaterials) for Electrically Small Antennas", 2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting (2020 IEEE AP-S/URSI), pp.1953-1954, Montréal, Québec, Canada on 5-10 July 2020.
“Metasurface for Controlling Polarization of Scattered EM Waves”, 4th Australian Microwave Symposium, 13th - 14th February, 2020, Sydney, Australia.
"Automated Reconfigurable Antenna Impedance for Optimum Power Transfer," 2019 IEEE Asia-Pacific Microwave Conference (APMC), Singapore, Singapore, 2019, pp. 1461-1463.
9) Table 2 presents an interesting comparison with state-of-the-art, but this table can be extended by providing more terms of comparison such as “design complexity, average radiation efficiency, operating bandwidth”.
10) Please support the conclusion with more numerical achievements.
11) Reference part needs to be improved by a proper extension as per above mentioned suggestions.
Author Response
Dear Reviewer,
Thank you very much for taking your time and considering our manuscript. We appreciate your valuable suggestions on our manuscript, which are very helpful to improve the overall quality of the manuscript. We have tried to answer your questions as much as we could and modified the manuscript based on your suggestions.
Best regards
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Authors have successfully addressed the reviewer's concerns. So, looking at the quality of the revised manuscript which shows a significant improvement than its initial version, there are no more technical comments.
