A New and Simple Design Method for End-Fire Dipole Antenna Array and Three Two-Element 24 GHz Planar End-Fire Dipole Antenna Arrays
Round 1
Reviewer 1 Report
The title is ambiguous and too long. The language in parts of the abstract is unclear. In the Introduction the authors refer to ‘chapter’. This is very odd! It’s still unclear why the frequency of 24 GHz has been chosen. Is there any application at this frequency? The antenna is a millimeter-wave design. Why are the authors referring to THz antennas? This shows lack of understanding. The theory presented is well established. The circuit model appears to be incorrect. There is no explanation given on the measurement setup.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
A brief summary of the contents of the manuscript
The presented article is devoted to the design of a simple structure of an end-fire antenna array end-fire using planar technology at a frequency of 24GHz. The authors of the article present three proposals for the solution of compact planar dipole antennas for high-gain end-fire antenna array. The actual results of the measurement of the designed and realized antenna and its simulation are objectively compared with the state of antenna technology of the same type from other publications. The work is thematically well focused. The authors demonstrate the practical ability to create something new and they can prove the results of their work by measuring. However, the theoretical explanation of the presented problem for the reader encounters a number of shortcomings.
Strengths of the manuscript
1 Implementation of three types of experimental antennas and measurements on such realized antennas.
2 Use of simulation program for analysis and verification of achieved results of realized and simulated antennas.
3 Objective measurements and comparison of the achieved results of the realized antenna with the results of antennas from other sources.
Weaknesses of the manuscript
According to the presented results, it can be concluded that the authors of the article have relatively good practical experience with antennas, but the professional text is very simple and has certain theoretical shortcomings. A number of shortcomings probably result from inattention and little consistency during the processing of the article. Figures 2, 4 and 6 in Chapter 2 and Figures 10, 11 and 12 in Chapter 4 visually expand and enrich the article, but the text to these figures is very austere and repetitive only with the exchange of numerical values. According to the title of the article, it is a methodology of antenna design, but the article presents only the design of the antenna design.
Main recommendations for improving the manuscript
1 Page 2, Chapter 2, Lines 67-70
The introductory text of Chapter 2 is not professionally well written. For example, in lines 67-70, there are three sentences that clearly confirm this fact. The first sentence says that "adjacent antenna elements are out of phase." Under this text, the authors probably think that there is a different phase on the adjacent antenna elements at a given moment. The second sentence states that: "when one is zero, the adjacent RF signal is also zero." Under this text, the authors probably think that when there is a zero phase on one element, there is also a zero phase on the other elements. Or the authors write about a "neighboring RF signal". However, the antenna is powered by a single RF signal. Under this text, the authors probably think that the radiated RF signal from an adjacent antenna element also has a zero phase. Or I write about a "neighboring RF signal". The antenna is powered by one RF signal. Under this text, the authors apparently think that the radiated RF signal from an adjacent antenna element also has a zero phase. The third sentence says: "when one is the maximum neighboring is the minimum". What do the authors think of maximum and minimum? The authors apparently thought it was a phase. But the signal phase is constantly changing in the range from 0º through 90º - 180º - 270º to 360º. Which phase value is the minimum and which is the maximum? Especially when phase 0º and phase 360º are the same phase value. In this case, the phase expresses the instantaneous value of the amplitude of the electric component of the electromagnetic field. The amplitude changes from the maximum positive amplitude value, through the zero value, to the maximum negative amplitude value. But the reader only has to guess all this.
2 Page 2, Chapter 2, Lines 91-92, Figures 2, 4, 6
In the text of Chapter 2 (lines 91.92) it is correctly stated: "In this circuit, the characteristic impedance of the transmission line Z0 is almost the same as the load of the dipole antenna ZL". From this text, it is clear that the impedance Z0 is the impedance of the supply line and the impedance ZL is the input impedance of the antenna. On the respective circuit models, the supply line with impedance Z0 is indicated on the left side of each of Figures 2 (b), 4 (b) and 6 (b). Then the input impedance of the antenna ZL is at the input terminals of each first circuit element (from the left side). However, these impedances (Z0, ZL) are not written in the figures. The admittances Y of the respective elements are written in these figures, but nothing is mentioned in the text. The impedance of the individual elements is not the same (Line 131), so a different current flows through each element. Also, the admittance as the inverse of the impedance cannot be the same on every element. But in each picture, all admittances are the same YL.
3 Page 5.6 Chapter 3, Lines 170-174, Table 1
The text of the article (Lines 170-174) states that Table 1 presents the simulation results. The table itself does not indicate that these are the results of the simulation. The article presents the results of the simulation in two places. In the first case, the simulation results are shown in Figures 3, 5 and 7, which are derived from mathematical relations. In the second case, the results of the antenna simulation program are shown in Figures 10, 11 and 12. However, the simulation results shown in Table 1 do not correspond to any of the above image files.
4 Page 8, Chapter 4, Figure 11 (b)
In Figures 10, 11 and 12, the graphs of the simulation results and the graphs of the measurement results have a different course. The simulation results have a round and smooth course and the measurement results have a tortuous and bumpy course. By comparing all these results in Figures (10, 11, 12), it can be stated that in Figure 11 (b) the designations "meas ↔ sim" are interchanged.
5 Page 9, Chapter 4, Lines 244-247
In the above text (Lines 244-247) it is correctly written that in Figures 11 and 12 the measured gain is greater than the simulated gain (meas> sim), while in Figure 10 the simulated gain is greater than the measured gain (sim> meas). This fact is very difficult to observe in Figures 10, 11 and 12 of the present article. Therefore, it would be appropriate for the authors to use higher quality images in the article and to state the value of the simulated gain for each image in the relevant text.
6 Page 6-9, Chapter 4
Formally, the text of the analysis of the three types of antennas in Chapter 4 is arranged unsystematic. Explanation: In Chapter 2, the text layout of the analyzed antennas is as follows: (1) without auxiliary elements; (2) with one auxiliary element; (3) with two auxiliary elements. In Chapter 3, the text layout of the analyzed antennas in Table 1 is the same: (1) without the auxiliary antenna; (2) with one auxiliary antenna; (3) with two auxiliary antennas. However, in Chapter 4, the text layout of the analyzed antennas is reversed: (1) with one auxiliary antenna; (2) without auxiliary antenna; (3) with two auxiliary antennas. This non-systematic arrangement of the text is misleading to the reader. With this non-system arrangement, the authors created a problem for themselves. Eg: Page 7, Chapter 4, Figure 11, Line 212-214. Under Figure 11, the authors stated: "antenna array with no auxiliary dipole antenna": But in the text of the article, the authors wrongly write about this Figure 11: "Figure 11 (b) (c) shows ... antenna array with 1 auxiliary dipole antenna". (Likewise, the authors write incorrectly in lines 194-196). It would be useful for the authors to put the text of the article and the text below the image in the right context.
7 Page 10, Chapter 5, Table 2
The above-mentioned formal discrepancy (point 6) probably also caused the discrepancy given in Table 2. Table 2 compares the gain results of the proposed antennas, achieved in the work with the gain of antennas from other publications. At the end of the table are the gains of the three antennas presented in the work as follows (from top to bottom): (1) 8.8dB with 1 auxiliary dipole; (2) 9.1dB with no auxiliary dipole; (3) 9.9dB with 2 auxiliary dipole. After a thorough analysis of the achieved antenna gains, presented in Figures 10 (b), 11 (b) and 12 (b)), this redistribution of gains does not correspond to reality. The antenna gain values listed in that order have interchanged antenna type designations. It should be written correctly in the table as follows: (1) 8.8dB with no auxiliary dipole; (2) 9.1dB with 1 auxiliary dipole; (3) 9.9dB with 2 auxiliary dipole.
Minor recommendations for improving handwriting
1 Page 2, Chapter 2, Line 61
The uppercase letter D, (line 61) cannot be confused with the lowercase letter d, (Figure 1). If “d” is the distance between the antenna elements, then “D” is the directionality of the antenna, as correctly stated on page 1 in Chapter 1, line 30. Similarly, it is (Page 5, Chapter 3, Figure 8 (b)) and (Page 6, Chapter 4, Line 189).
2 Page 2, Chapter 2, Lines 62-63
Line 62 describes the value of parameter M. For a more detailed explanation of parameter M, line 63 refers to an example from reference [6], where M = 1. After a closer examination of reference [6], such an example and parameter M are not found in this literature at all. .
3 Page 2, 3, 4, Chapter 2
The introduction of Chapter 2 describes the parameters of antennas L, d, M and N, which, however, are not applied anywhere in the work. Chapter 2 gives three specific examples (1), (2), (3) of the proposed antenna solution. In order that the stated parameters of these antennas do not appear only in the abstract, it would be appropriate for each example of the proposed antenna to state specific values of these parameters.
4 Page 3, 4, Chapter 2, Figure 4, 6
In Figures 4 (a) and 6 (a), the individual antenna elements are denoted by the IM index with the corresponding element serial number. As a rule, the sequence number of the antenna element in Figures 4 (a) and 6 (a) should correspond to the sequence numbers of the currents in Figures 4 (b) and 6 (b). But this is not the case in the pictures. For example, in Figure 6 (a) the order of the elements is from left to right (IM1, IM3, IM4, IM2) and in Figure 6 (b) the sequence number of the currents is: (I1, I2, I3, I4). The order should be correct: (I1, I3, I4, I2).
5 Page 4, Chapter 2, Line 131
The sentence (Line 131) should state correctly: "ratio of currents of four dipole antennas"! Not like this: "the ratio of the currents of three dipole antennas".
More suggestions for improving the handwriting
1 Page 3, 4, Chapter 2, Figure 4, 6
In each of Figures 4 and 6 are two smaller figures which are not indicated by the letters (a) (b).
2 Page 4, Chapter 2, Figure 6
Under Figure 6 there is no designation for the second part of the picture - 6 (b)
3 Page 4, Chapter 2, Line 131
There is not the same notation in the text of the mathematical ratio on the left and on the right side of the relation in line 131: (illustration of incorrect notation) Z:Z:Z:Z=X: X: X :X
4 Page 3,4, Chapter 2, Figures 3,5,6,7
The descriptions below Figures 3, 5, 6 and 7 have a sentence that begins with lowercase letters.
5 Throughout the article
There should be a space between the description of the images and the following text of the article.
6 Page 5.6, Chapter 3, Line 170, Table 1 and Page 10, Chapter 5, Line 252, Table 2
The designations "Table 1, (2)" have the Latin numbers 1 (2) in the headings of the tables themselves. In the text of the article, these tables are marked "Table I, (II)" with the Greek numerals I, (II). As these are the same tables in the text of the article, it is necessary to unify the font.
7 Page 6, Chapter 3, Table 1
What is the meaning of the number 1 in the title "Title 1"? If the title "Title 2" is not mentioned in the whole article. What does the at sign "@" mean in the heading "S11_sim @ 24 GHz" mean?
8 Page 10, Chapter 5, Table 2
In the header of the table is the heading "topology" with a small "t"! The header of Table 2 is not highlighted as it is in Table 1.
9 Page 11, References
References: 1 - A different way of mentioning the author than for all other references. References: 1, 2, 3, 4, 5, 6 - After the surname and the abbreviation of the name, the abbreviations of the name and surname of the authors are repeatedly inserted. References: 7 - No year of publication indicated. References: Uneven typeface to indicate years of publication.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The directional antenna has significant backscatter radiation. The authors are implying of using this type of antenna for on-chip THz systems. It’s obvious fabrication of THz antennas is expensive. This type of antenna is not feasible for on-chip antenna because the integrated circuit below it will present a conductive layer which will distort the radiation characteristics. The theory of such antenna’s is well documented in books and literature. There is nothing new about the theory. The English language in various parts of the paper is unclear. The description of the measurements is didactic and not explained well. There is nothing new or of significance in the end-fire antenna presented. Also, the quality of the paper falls short of a journal paper.
Reviewer 2 Report
A brief summary of the contents of the manuscript
The article submitted for review is devoted to the design of a simple structure of the terminal fire of an antenna array using planar technology at a frequency of 24 GHz. The authors of the article present three proposals for the solution of compact planar dipole antennas for a system of antenna end fires with high gain. The actual measurement results of the designed and implemented antenna and its simulation are objectively compared with the state of antenna technology of the same type from other publications. The work is thematically well focused. Authors have the ability to create something new and present their research activities in the form of measurement results and the grant of a patent..
Strengths of the manuscript
1 Implementation of three types of experimental antennas and measurements on such realized antennas.
2 Use of simulation program for analysis and verification of achieved results of realized and simulated antennas.
3 Objective measurements and comparison of the achieved results of the realized antenna with the results of antennas from other sources.
4 Granting of a patent for the presented antenna system.
Weaknesses of the manuscript
According to the presented results, it can be concluded that the authors of the article have relatively good practical experience with antennas. The professional text, which originally had certain theoretical shortcomings, was removed by the authors after review. The original weaknesses of the manuscript resulting from inattention and repetitive text were also removed by the authors.
Recommendations for improving the handwriting
When reviewing the article, the reviewer presented the authors with several more demanding and also simpler recommendations for improving the manuscript. Several recommendations were also made for the formal editing of the article. The authors accepted these recommendations and the article was moved to a higher level of quality. The authors proceeded to slightly modify the title of the article, which I also consider a positive contribution.
After reading the first recommendation of the reviewer, concerning the three sentences of the text (1. Page 2, Chapter 2, Lines 67-70), the authors proceeded to delete them. Although, as a reviewer, I assumed that the three sentences would be modified by the authors in the spirit of the instructions that were in the text of this recommendation. But as a reviewer, I also agree with deleting these sentences.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The paper is very interesting to readers. I have minor comments to improve the quality of the paper. Please find my comments below.
- In the abstract, please provide the full name of EIRP.
- I suggest authors to send the paper to English proofreading.
- Half power beam width should be abbreviated as HPBW in line 31
- Define mm-wave as a abbreviation in line 34.
- Please revise the sentence in line 12 starting from “Methods:….”
- Please rewrite the sentences in line 132-134 “Compared with antenna array in reference [8], antenna array in reference [8] is not realized in planar technology. Compared with antenna array in reference [9], antenna array in reference [9] requires impedance matching network between elements”
- I suggest authors to improve the quality of Figure 4.
- I suggest authors to compare the dipole antennas operating same or similar frequency range in Table 2.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
Abstract section doesn’t need to include background and conclusion. It just needs to include overall summary on the work. Please note, designing high output power transmitters is not a difficult task. High power amplifiers will do the job. Why is design at 24 GHz picked? The design of end-fire antenna’s is well established. The authors have used dual element with auxiliary dipole antennas. The works lacks details theoretical analysis and rigor given. The comparison in Table 2 is not valid. The references cited are old and not mm-wave end-fire antennas. There are many mm-wave end-fire antennas to compare with.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
In the article, the authors present a new methodology for the design of an antenna field structure with a trailing fire at a frequency of 24GHz, without harmonization of networks between antenna elements. To this end, they present a well-known theory on this problem, on the basis of which they explain their innovative approach to the technical design of an antenna field with a tail fire, for which a patent has been granted. The achieved results of simulation and measurement objectively compare with the current state of this antenna technology in the world.
The work has a number of minor shortcomings that can occur in word processing. I consider some points of shortcomings based on the written text (5, 8, 10) and also some points mentioned in the conclusion of the article (13, 14, 15) to be more serious. When editing them, authors should be careful that the article does not lose its meaning.
1. Page 1, Citation: next to the abstract
The author E S. is missing the comma after the surname E, S.
2. Page 1, Chapter 1
The introductory chapter of the article should contain a brief description of the content of the work according to the chapters, which is not in this introduction.
3. Page 2, Chapter 2, Lines 48-53
The text states that: "N - is the number of antenna dipoles, where usually d = M*λ/4, M = 1, 2, 3…", but N is no longer stated in the relation. It would be appropriate to state in the text what the letter N expresses and what the letter M expresses.
4. Page 2, Chapter 2, Figure 1 (a)
If we consider according to Figure 1 (a) that the distance d is the distance only between the antenna elements and we do not consider the diameter of the antenna elements themselves, then the relationship under Figure L = (N - 1) d is incorrect. It is not clear from Figure 1 (a) and the corresponding text what the three arrows pointing up at the top right indicate. If it were to be the third Y axis, then one arrow would suffice, at the first dipole. If the three arrows indicate the direction of radiation of the antenna field "end-fire", then such a field (as shown) radiates along the Z axis and not in the upper right.
5. Page 2, Chapter 2, Figure 1 (b)
From the description of Figure 1 (b) and from Figure 2 (b) it is clear that the antenna dipoles have a length l = λ/2. One half-wave antenna dipole (l = λ/2) consists of two arms, each arm having a length l = λ/4. Visually, the dimension (λ/2) marked in Figure 1 (b) corresponds to the length of only one arm of the half-wave dipole (λ/4).
According to the description of Figure 1 (a) and 1 (b), the distance between the individual half-wave dipoles should be the same, i. d = λ/2. At first glance, however, it can be seen that the distance between the dipoles (IM1 - IM2) is different - greater than between the dipoles (IM2 - IM3).
The antenna (Figure 1 (b)) shows the distribution of the HF signal, which should have a harmonic cosine waveform. The signal distribution shown is not cosine. This inappropriately distorted waveform of the RF signal degrades an article in a professional journal: "Applied sciences".
6. Page 2, Chapter 3, Figure 2 (a)
The orientation of the three-dimensional Cartesian coordinate system (x, y, z) shown in Figure 2 (a), does not correspond to the orientation of the coordinate system in Figure 1, according to which the theory is described.
7. Page 2, Chapter 3, Figure 2 (b)
The parameter L, which expresses the dimension of the antenna half-wave dipole in Figure 2 (b), does not correspond to the parameter L, which expresses the total length of the antenna in Figure 1(a). Usually, the total length of the antenna is indicated as an uppercase letter L and the length of the dipole as a lowercase letter l.
8. Page 2a3, Chapter 3, Figure 2 (a)
The authors convince the reader that in Figure 2, where an antenna with three antenna dipole elements (HWDP1, HWDP2 and HWDP3) is realized, there is a two-element antenna array.
This discrepancy means that the theory from Chapter 1 does not match the description of the antenna in Chapter 2! Then it would be necessary to amend or supplement the theory in Chapter 1 so that it fits into the implemented antenna in Chapter 2.
9. Page 3, Chapter 3, Table 1
Why is there a "sim" (small letter - s) in the second column of Table 1 and a Sim (capital letter - S) in the third column?
What is the meaning of "@ 24" in the header of the second column "S11_sim @ 24 GHz"?
10. Page 3, Chapter 4, Line 111
According to the title of the article, the presented work presents a simple methodology for the design of an end-fire antenna array. But the "dry" statement of the text (line 111) "after optimization of the antenna array" does not indicate that it is a design methodology. The mentioned parameters L, D1, D2 and D3 are unambiguously given in the work, because they express the value of the working frequency. It would be appropriate for the authors to specify in more detail their idea of how to optimize these parameters.
11. Page 4, Chapter 4, Line 119,120
The value of cross-polarization in dB is usually given in negative values.
12. Page 4, Chapter 4, Figure 4 (b) and 4 (c)
In order to present the results of the simulations and the measured characteristics of the antenna (in the X-Y and X-Z planes), Figures 4 (b) and 4 (c) are unsuitable for publication. Images are small, indistinct, unclear and illegible.
Figure 4 (c) also has non-standard marking of positional measurement angles.
13. Page 5, Chapter 6, Lines 146-147
The stated rule that "for mm wave signals and THz wavelength decreases with increasing frequency" applies in the whole frequency spectrum, not only in the mm wave band.
14. Page 5, Chapter 6, Lines 146-149
National frequency spectrum tables consider the use of frequencies only up to about 300GHz. At higher frequencies in the THz region, the atmosphere has a large attenuation and is opaque for radio connections and the THz frequency is unusable.
15. Page 5, Chapter 6, Lines 149-151
Slotted antennas belong to the group of planar antennas, which have a different way of power supply, radiation and polarization, which this work does not solve.
16. Page 5, References
Authors in this area have not published articles yet?
After eliminating shortcomings, the topic presented in the article may be of interest to the professional public.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
[Previous comment] Abstract section doesn’t need to include background and conclusion. It just needs to include overall summary on the work.
[Revised version] THIS HAS NOT BEEN CHANGED. THE AUTHORS NEED TO SEE HOW OTHER ARTICLES WRITE ABSTRACTS.
[Previous comment] Why is design at 24 GHz picked?
THIS HAS NOT BEEN ANSWERED IN THE REVISED VERSION.
[Previous comment] The design of end-fire antenna’s is well established. The authors have used dual element with auxiliary dipole antennas. The works lacks details theoretical analysis and rigor given.
[Revised version] NO RGOROUS THEORICAL ANALYSIS IS INCLUDED.
The comparison in Table 2 is not valid. The references cited are old and not mm-wave end-fire antennas. There are many mm-wave end-fire antennas to compare with.
[Revised version] NOTE, REF.[9] YEAR IS MISSING. THERE AUTHORS SHOULD HAVE COMPARED WITH MORE RECENT 2020 & 2021 REFERENCES e.g.
Ao Li;Kwai-Man Luk, “Millimeter-Wave End-Fire Magneto-Electric Dipole Antenna and Arrays With Asymmetrical Substrate Integrated Coaxial Line Feed,” IEEE Open Journal of Antennas and Propagation, 2021, Vol.2.
Jingtao Zeng;Kwai-Man Luk, Wideband Millimeter-Wave End-Fire Magnetoelectric Dipole Antenna With Microstrip-Line Feed, IEEE Transactions on Antennas and Propagation, 2020, Vo. 68.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
I agree with all the corrections made in the article.
Point 2. The proposed additional text can be inserted in Chapter 1. However, the content of this text does not refer to the chapters of the article.
Therefore, I propose to divide the text into four sentences and assign a chapter number in each sentence, which solves the described problem.
Insert the text thus amended and modified at the end of Chapter 1.
Proposal:
In order to fulfill the aim of the article and explain the essence of the problem, the second chapter presents a general theory of the end fire antenna, which includes a new and simple methodology for designing a design solution of the field of this type of antenna.
To verify this new methodology of the field solution, a compact planar two-element two-pole terminal fire dipole antenna with high gain is designed and implemented, the third chapter discusses.
The fourth chapter verifies the results of measurements on a realized dipole antenna with the results of simulations on such an antenna operating in the frequency band 24 GHz.
In the fifth chapter, the achieved results are briefly commented and compared with the state of antenna technology in this area in the world.
I also noticed the abstract more, I recommend editing:
The content of an article abstract is in a way an "advertisement" of the article.
If the reader reads the abstract, the article should interest him.
Therefore, sentences should not start with the word "Background" but for example:
The article solves one of the challenging tasks of RF transmitter design ...
Or use instead of the word "Methods":
The work presents a proposal .... and a design solution ....
Or replace the word "Results" with:
The achieved result is an antenna with a gain of 8.8 dBi ...
If necessary, replace the word "Conclusions" with the sentence:
The benefit of the work is a new simple design ...
The continuation of sentences needs to be stylistically and grammatically adjusted.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
