Review Reports

Round 1

Reviewer 1 Report

Please check the attached file

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Title: ULTRA-WIDEBAND LOW-COST HIGH-EFFICIENCY CAVITY-BACKED COMPOUND SPIRAL ANTENNA

 

Comment: The antenna is very good, have an ultra-wideband of impedance bandwidth and AR.

 

For improvement:

1. In line 1: Abstract: A low-cost high-efficiency ultra-wideband (UWB) cavity-backed spiral antenna is proposed.

In line 29-30 The laminate cost is important when the antenna is large (frequencies of operation are low), which is the case considered here.

 

Please give more information about a low cost. Actually, we can also buy a low-cost antenna in the market.

2. In line 21-23: the typical 50-Ω feed to the spiral’s input. High-permittivity thick substrates can reduce the spiral’s input impedance but at the cost of narrower impedance and axial-ratio (AR) bandwidths [15,16].

Also, designing a spiral antenna for unidirectional radiation comes at a price

In line 27-28: feasible when the impedance bandwidth must exceed 10:1 ratio. On the other hand, the absorbers decrease the radiation efficiency, which is particularly unwanted when low-cost laminates (e.g., FR-4) 29 are used since their loss is already high.

 

Please give a table as comparison of yours to references

 

3. In line 82-85. This is attributed to the high uncertainty in the properties of the FR-4 substrate, which 85 are not provided by the manufacturer in the GHz range.

 

In figure 5. The simulated reflection coefficient of the proposed antenna shows wide different too among CST and HFSS, especially from 2 GHz to 5 GHz.

Please give the reason?

 

4. In figure 8, Contour plots of the measured AR at 0.5 GHz, 4.0 GHz, and 5.0 GHz. The interval is not equal

Please add one contour plot in 2 or 3 GHz too, if possible.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

This paper presented the design of an ultra-wideband cavity-backed compound spiral antenna. The paper is well written and organized in a clear, precise manner. Here are the reviewer’s comments:

1. The performance of the balun should be included in Section 2.

1. Further literature survey needs to be conducted and the below references should be included in the introduction.

R1. "Cavity-backed two-arm spiral antenna with a ring-shaped absorber for partial discharge diagnosis," J. Electr. Eng. Technol., vol. 8, no. 4, pp. 856-862, Jul. 2013

R2. "3D-printed super-wideband Spidron fractal cube antenna with laminated copper," Appl. Sci., vol. 7, no. 10, p. 979, Sep. 2017

R3. “Planar super-wideband loop antenna with asymmetric coplanar strip feed," Electron. Lett., vol. 52, no. 2, pp. 96-98, Jan. 2016

2. The author should provide a comparison between the proposed antenna and the antenna in previous works to clarify the advantages of this antenna.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf