Design of a MIMO Antenna with High Gain and Enhanced Isolation for WLAN Applications

Round 1

Reviewer 1 Report

Key word in the tile of paper is 'isolation' between port, however, authors show s21 for the optimized antenna. How they have achieved/optimized the antenna and which parameters have more effect are not shown or discussed.

The influence of H-shaped etching and stub on ground plane and also step shaped stub connected to radiating elements are not discussed. 

1-why increasing R1 degrades matching?

2-for simulations in Figs. 2 and 3, what are values of other parameters?

3-what is active reflection coefficient?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Authors present a dual band MIMO antenna with enhanced isolation for WLAN applications. Authors proposes two semicircular annular with zigzag rectangular microstrips placed symmetrically in the radiation units. Two h-slots are etched in the ground plane to affect the current distribution, reduce the coupling between ports and thus increase the isolation between antenna elements. Comparison between simulations and measurement show a relatively good agrement of the results.

As comments, the following should be addressed in the potential revised version:

0) A table with the specifications of the antenna shall be included before describing the design process to check is the presented antenna fulfils the requirements.
1) Authors shall explain why a shift of the resonant frequencies appears in the prototype (figure 6). 
2) The envelope correlation coefficient (ECC) is presented as a measure of the correlation between communication chnnels. Authors claim that if ECC<0.3 the capacity is increased significantly. Why 0.3 and not 0.2? Further explanations or references shuld be provided to support this value.
3) Directive antenna is possibly a misleading name for the antenna. Authors are enconuraged to proopsed a modified name for the paper.
4) Information about the polarization of the antenna is not included.
5) Which is the simulation software used for antenna design?
6) Information on the process of optimization of the dimensions shall be provided.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

A MIMO antenna for WLAN applications operating in 2.4 GHz and 5.8 GHz frequency bands is presented.

Line 40: area of 50x40mm e.g 200mm^2...

Line 45/46: the authors should compare their results with other works.

Lines 80-84: non formatted. This information should be presented in a table..

The simulation curve presented in figure 6 corresponds to what R1 in figure 2?

The measurement methods and equipments should be explained/presented in the paper.

The conclusions should be improved. It only summarize the work preformed. The authors indicated that the proposed antenna is an  alternative to WLAN applications for mobile terminals. It should be done a new section ( Related Work, for example ) where the authors compare the topology of other antennas.

The authors should use works for the state of the art more recent than 2017.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Answers don't fulfill the 3 questions of 1st review.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Should revise the text, some misspelled words, sentences.

Author Response

We have revised the manuscripts.