An Inner- and Outer-Fed Dual-Arm Archimedean Spiral Antenna for Generating Multiple Orbital Angular Momentum Modes

Round 1

Reviewer 1 Report

Title: “An inner-outer-fed dual-arm Archimedean spiral antenna for generating multiple orbital angular momentum modes”

The topic of the submission is interesting and practical. After going through the manuscript following

observations are made and authors must address them before acceptance.

In this paper, a dual-arm Archimedean spiral antenna (DASA) is proposed to generate multiple OAM states with positive and negative values by feeding at the inner- and outer-ends, respectively. Dual-mode OAM states are generated at different working frequencies (l= ±1 at 3GHz, l= ±2 at 4GHz and l= ±3 at 4.8GHz). The concept is validated by simulation as well as by experiment. I will recommend the manuscript after answering the following questions:

(1)   Please change return loss to reflection coefficient in the manuscript. I will recommend to read “Definition and misuse of return loss” by TS Bird.

(2)   It is alos strongly suggested that the authors of the paper  provide the simulation vs measured S11 plot as well.

(3)   The authors of the paper need to  provide the radiation pattern for more clarification.

(4)   Kindly update with the simulated radiation efficiency as well.

(5)   It is also recommended for the authors to  prepare a comparison table at the end to show the superiority of their work in a better way.

(6)   The authors mentioned Archimedean spiral and other structure which have attracted researcher’s attentions due to its broad bandwidth. In this regard, authors must add these papers in their literature review:

•             Sensors 2018, 18(9), 3155

•             Sensors 2018, 18(10), 3330

•             Compact UWB band-notched antenna with integrated bluetooth for personal wireless communication and UWB applications, Electronics, 2019.

All in all, the paper is not recommended for publication in its present form and needs major revision.

Author Response

See the attatched file.

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors have designed and fabricated a dual arm Archimedean spiral antenna for generating multiple orbital angular modes in communication and imaging applications. Although the design of the study, antenna design approach, analytical methods employed, results and conclusions derived in terms of the DASA's quantitative advantages are sound, the manuscript could benefit extensively from an improvement in syntax, grammar and spelling errors which are extensive. 

Elsewhere, I have the following comments: 

1- Line 20-22: Despite this being the abstract, please articulate what the salient qualitative result is of the OAM modes at the three frequencies. This has been done in the conclusions section. 

2- Line 32- Use the exponential notation to delineate that term instead of exp(...

3- Line 81- Please list which specific FE method was incorporated into the home-built EM simulation program. 

4- Lines 217-219 - This sentence was not clear especially with respect to the alignment of the two axes. 

5-  Line 161 - Reference Fig 4b here in support of employing a height (h1) of 80 mm for enhanced gain. 

Author Response

See the attatched file.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The paper is well improved and nearly most of the comments are responded.

The plagerism of the paper checked by ithenticate was also 18%. which can also be imprived.

Regarding comment 6,

Since the authors mentioned Archimedean spiral and other structure which have attracted researcher’s attentions due to its broad bandwidth,The reviewer believe that the authors must cite the following paper published in 2019 in Electronics journal.

Electronics 2019, 8(2), 158; https://doi.org/10.3390/electronics8020158 

Compact UWB Band-Notched Antenna with Integrated Bluetooth for Personal Wireless Communication and UWB Applications

All in all, the paper needs minor revision

Reviewer 2 Report

The authors have addressed most comments with the exception of significantly improving the syntax. A more careful review could help eliminate breakdowns in sentence composition and make for a clearer article. They are encouraged to undertake such edits. .