Design of a Wideband L-Shape Fed Microstrip Patch Antenna Backed by Conductor Plane for Medical Body Area Network

Round 1

Reviewer 1 Report

The paper describes compact L-shaped microstrip patch antenna backed by conductor plane for medical body area network. The author has presented proximity L-shape coupled microstrip patch antenna for wider impedance bandwidth operation. And then, by utilizing conductor plane with air foam gap between antenna ground plane and body, the author has also demonstrated that the anti-body effect featuring degradation of antenna performance can be reduced. Finally, the antenna performance with and without body loading effect has been compared by measuring the S-parameter and radiation patterns. Although the authors claimed the novelty of the presented antenna, the designed antenna is not clearly characterized, such as broadband and reflector characteristics. In order to prove the novelty of this paper, please find lots of comments below.

Please define the exact operating mechanism about on-body and off-body communication. The reviewer thinks that the on-body communication define the propagation methodology flowing through the body surface, not the propagation methodology about proximity effect between antenna and body. Please refer to the attached paper.

- A. Pellegrini, A. Brizzi, L. Zhang, K. Ali, Y. Hao, X. Wu, C. C. Constantinuou, Y. Nechayev, P. S. Hall, N. Chahat, M. Zhadobov, and R. Sauleau, “Antennas and propagation for body-centric wireless communications at millimeter-wave frequencies: A Review,” IEEE Antennas and Propagation Magazine, vol. 55, no. 4, pp. 263–287, 2013.

The reviewer recommends that the author should change the “on-body” and “off-body” word in the revised manuscript.

Please refer to the attached paper.

- T. Bird, “Definition and misuse of return loss,” IEEE Antennas and Propagation Magazine, vol. 51, no. 2, pp. 166–167, 2009.

The author should use the “reflection coefficient” or “VSWR”, not “return-loss” in the revised manuscript.

Please insert the coordinate systems in Fig. 1, 5(b), insets of Fig. 6, Fig. 8, insets of Fig. 9. And the reviewer recommends that the current coordinate systems should be changed to other coordinate systems because it can be confused about dual-polarization or circular-polarization in Fig. 11 and 12. In Fig. 11 and 12, it seems that the main polarization is dual (i.e. E_phi @ xz plane and E_theta @ yz plane). In addition, to improve readability in Fig. 11 and 12, the scale in radiation patterns should be changed. At the first paragraph of introduction part, the author described ISM band and UWB band for WBAN communication systems. However, to improve readability for the future reader, the reference paper about some applications at UWB band for WBAN communication should be additionally inserted. The reviewer cannot agree with the author’s opinion about broad bandwidth of the designed antenna. The author should change the manuscript title by using “wideband”, not “broadband”. In Table 3, the maximum gain between other state-of-art wearable antenna without body effect (in free space) has been compared. However, because this designed antenna is wearable antenna type, the author should compare with the maximum gain between other wearable antenna with proximity coupled body effect. Please verify the exact effect by using additional backed by conductor plane. The reviewer cannot regard the conductor plane as a reflector. Despite the absence of backed by conductor plane, the reviewer think that the increasing size of ground plane of original patch antenna is more effective method to enhance antenna performance. Otherwise, the reviewer recommend the antenna backed by EBG reflectors.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Amendments in accordance to suggestions by reviewer 1 are showed in green color in the revised manuscript.

Author Response File: Author Response.pdf

Reviewer 2 Report

Abstract:

In the Abstract the conducting plate is placed at 2mm below for the operating frequency. However, the Operating frequency is 2.45 GHz. Its need to be cleared why conducting plate calculation is done at 2.4 GHZ. Other dimension need to be included like why not 1.5 mm or 2 mm. Needs to add more information.

 

Section 2: Antenna Design

For impedance matching it needs to include the smith chart as it describes visually well where the antenna matched well or not. It was not clear to me why the antenna is 50mm X 50 mm. Is there any size constraint for this type of geometry?

For impedance matching include smith chart

One figure needs to include in this section, radiation efficiency vs. frequency.

One figure needs to include here: 3D radiation pattern. Its easy and accessible  from all available software.

 

Conclusion section is missing future works. Any research work needs some improvement always

Author Response

Please see the attachment.

Amendments in accordance to suggestions by reviewer 2 are showed in blue color in the revised manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thanks for your revised papers. But the authors still use lots of wrong expression and it seems that the authors do not totally agree with the reviewer’s comments. To prove the novelty of this paper, please find lots of comments below and revise this current manuscript.

 

1. Please again define the exact operating mechanism about on-body and off-body communication. The reviewer thinks that the on-body communication define the wave propagation methodology flowing through the body surface, not loading proximity body effect. Please refer to another attached paper.

- G. A. Conway and W. G. Scanlon, “Antennas for over-body-surface communication at 2.45 GHz,” IEEE Transactions on Antennas and Propagation, vol. 57, no. 4, pp. 844–855, 2009.

In order to avoid any confusion of physical meaning usage, the reviewer comments that the propagation direction in off-body communication is normal to the body surface such as broadside radiation of patch antenna. And the propagation direction in on-body communication is tangential to the body surface such as end-fire radiation of linear antenna (i.e. horizontal monopole or dipole antenna). So the reviewer recommends that the author should change the “on-body” and “off-body” word in the revised manuscript.

2. The author still use both “S11 (dB)“ and ”reflection coefficient (dB)” in the revised manuscript. Please unify the same expression to improve the readability of the revised manuscript. The reviewer thinks that the “reflection coefficient (dB)” is better than “S11 (dB)”.

3. When the separation gap is different in Fig. 7, there is interaction effect between body and antenna with additional ground plane. But the reviewer is still worried about the additional ground plane as a reflector. What is the exactly physical function of the additional ground plane (i.e. in-phase reflection or quadratic reflection phase,…)?

4. The I-shaped element metasurface for artificial magnetic conductor (AMC) like EBG structures can become promising candidates to reduce the anti-body effect with same entire volume of antenna. Please refer to the attached paper.

- Z. H. Jiang, D. E. Brocker, P. E. Sieber, and D. H. Werner, “A compact, low-profile metasurface-enabled antenna for wearable medical body-area network devices,” IEEE Transactions on Antennas and Propagation, vol. 62, no. 8, pp. 4021–4030, 2014.

Moreover, the body loading effect with EBG-backed antenna has little impact because the gain in the main lobe is rarely changed at Fig. 13 in the reference [8].

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

I think this time paper quality is improved significantly. It can be accepted.

Author Response

Authors would like to extend their appreciation to reviewer 2 for giving valuables comments and suggestions to improve the quality of the manuscript. Second revision of the manuscript is submitted mainly to fulfill reviewer 1’s requests, as follows:

Change “on-body scenario” word to antenna on the human body, and “off-body scenario” word to antenna in the free space to enhance the readability of the manuscript. “S11” and “reflection coefficient” were used to describe reflection coefficient at the input port of the antenna. Reviewer 1 recommended authors to use “reflection coefficient” instead of “S11” to enhance the readability of the manuscript.

Revisions on the latest revised manuscript were merely on standardizing technical terms in the manuscript to fulfill reviewer 1’s requests. Comment 2 involved long working hours as the usage of “S11” were widely used in the main text, axis and legend in most figures, and caption of figures. 

No additional figures or new contents were added to the revised manuscript.  

Round 3

Reviewer 1 Report

Thanks for your second revised papers. However, to prove the novelty of this manuscript as kind of SCI papers, please refer to two important comments and revise the future manuscript.

Figure 7

But the reviewer recommend that the authors should change the contents at Fig. 7. In Fig. 7, there is the simulated results of separation distance between the proposed P-fed I-shape MSA and conductor plate. But, in free space, was it utilized by different antenna sample? The reviewer thinks that the simulated gain in free space (red line) should be identical in case of same antenna sample. Otherwise, the reviewer recommends that the compared gain along the separation distance should be shown by using only one figure to improve the readability for future readers.

Academic novelty about the presented antenna type in the current manuscript

L-shape fed microstrip patch antenna has been already known in antenna society. The antenna backed by conductor plane for medical BAN applications to suppress the radiation energy such as back lobe is also stale techniques. Because the reviewer can catch the authors’ developing potential in two review steps, the reviewer recommends that the authors do research about the advanced antenna design techniques by using metasurface-based antenna and leaky wave antenna in the same WBAN applications for acceptable SCI paper.

Comments for author File: Comments.pdf

Author Response

We are sorry that comments given could not be implemented in the present work.

Please see the attachment for our reply.

Author Response File: Author Response.pdf