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arxiv: 2605.01631 · v1 · submitted 2026-05-02 · 📡 eess.SP

A Wideband Narrow Beam 1x6 Linear Antenna Array for Automotive Radar and 5G Millimetre-Wave Applications

Muhammad Asfar Saeed , Augustine O. Nwajana This is my paper

Pith reviewed 2026-05-09 17:36 UTC · model grok-4.3

classification 📡 eess.SP
keywords microstrip antenna array1x6 linear arrayautomotive radar5G mm-wavenarrow beamwidthwidebandhigh directivityreflection coefficient
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The pith

A 1x6 microstrip patch array with narrow interconnects produces a narrow high-directivity beam and reflection coefficient better than 10 dB for automotive radar and 5G mm-wave use.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper designs a linear array of six rectangular microstrip patches in which the first patch is directly fed by a microstrip line and the remaining patches connect through 0.1 mm wide lines that distribute power along the structure. Optimal spacing between the elements is selected so the radiated waves interfere constructively in the forward direction to produce a narrow beam while the array remains well matched over a wide frequency band. The six-element layout plus precise impedance matching is said to deliver the high directivity needed for high-resolution sensing and high-capacity links. A reader would care because the result offers a compact printed solution that could fit into vehicle radar units and 5G infrastructure without requiring complex feeding networks.

Core claim

The paper presents the design of a 1x6 linear microstrip patch antenna array made of six rectangular radiating patches, with the primary patch excited by a microstrip feedline and the others interconnected by narrow 0.1 mm microstrip lines that enable effective power distribution. Optimal inter-element spacing is used to create constructive and destructive interference that forms a narrow beam with enhanced directivity together with a wide operational bandwidth. The combined effects of the six-element configuration and precise impedance matching produce high-gain radiation characteristics. Analysis of reflection coefficient, current distribution, and radiation patterns shows performance with

What carries the argument

The 1x6 linear array of rectangular patches joined by 0.1 mm wide microstrip lines that distribute power and form the narrow beam through controlled interference.

Load-bearing premise

The simulated or measured electrical performance will carry over to actual fabricated hardware without large changes from manufacturing tolerances, substrate variations, or coupling effects.

What would settle it

Fabricating the array and obtaining a reflection coefficient that is not better than 10 dB across the target band or a beamwidth substantially wider than reported would show the design fails to deliver the claimed suitability.

Figures

Figures reproduced from arXiv: 2605.01631 by Augustine O. Nwajana, Muhammad Asfar Saeed.

Figure 1
Figure 1. Figure 1: Wideband antenna array applications in vehicles and 5G network communications view at source ↗
Figure 2
Figure 2. Figure 2: Layout of the proposed 1x6 linear antenna array. The antenna array employs a microstrip line feeding method, which offers a compact, low-profile solution that is easy to fabricate and suitable for integration with printed circuit boards. This method also supports precise impedance matching and can be readily optimized for various high￾frequency applications. The first radiating patch is directly excited vi… view at source ↗
Figure 4
Figure 4. Figure 4: Reflection coefficients of the proposed 1x6 linear antenna array view at source ↗
Figure 5
Figure 5. Figure 5: 3dB radiation patterns of the proposed 1×6 linear antenna array at 28 GHz, showing the radiation cuts in the ϕ = 0° and ϕ = 90° planes. The surface current distribution of the proposed 1×6 linear microstrip patch antenna array was analysed at 28 GHz to evaluate the excitation behaviour and electromagnetic energy flow across the structure. As shown in view at source ↗
Figure 6
Figure 6. Figure 6: Surface current distribution of the 1x6 linear antenna array. IV. CONCLUSION In this work, a compact high-frequency microstrip patch antenna was designed, simulated, fabricated, and analysed for 28 GHz applications, particularly targeting 5G and mm-wave wireless communication systems. The antenna design focused on achieving high gain, proper impedance matching, and directional radiation patterns while main… view at source ↗
read the original abstract

This paper presents the design and performance analysis of a 1x6 linear microstrip patch antenna array tailored for automotive radar and 5G millimetre-wave (mm-wave) applications. The proposed antenna array comprises six rectangular radiating patches with the primary patch excited using a microstrip feedline, while the remaining patches are interconnected through narrow microstrip lines with a width of 0.1 mm, enabling effective power distribution along the array. Optimal inter-element spacing facilitates constructive and destructive interference, enabling the formation of a narrow beam with enhanced directivity and a wide operational bandwidth. The high-gain radiation characteristics are achieved through the combined effects of the six-element linear configuration and precise impedance matching. Key performance metrics including reflection coefficient, current distribution, and radiation patterns have been analysed. Results demonstrate a reflection coefficient better than 10 dB across the target frequency range and a narrow beamwidth with high directivity, making the array suitable for high-resolution automotive radar and 5G mm-wave communications. Potential applications include vehicle-to-vehicle (V2V) radar sensing, lane change detection, blind spot monitoring at 28 GHz, and high-capacity point-to-point wireless backhaul links. The design offers a promising solution for compact, high-performance beamforming antenna systems in intelligent transportation and next-generation wireless networks.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

3 major / 3 minor

Summary. The manuscript describes the design of a 1x6 series-fed linear microstrip patch antenna array operating at 28 GHz for automotive radar and 5G mm-wave applications. Six rectangular patches are used, with the first excited by a microstrip feed and the others connected via 0.1 mm wide lines for power distribution; inter-element spacing is chosen to produce a narrow beam. Performance is evaluated via electromagnetic simulation, with reported results including reflection coefficient better than -10 dB across the target band, current distributions, and radiation patterns showing high directivity and narrow beamwidth. The design is positioned as suitable for V2V radar, lane-change detection, and point-to-point backhaul.

Significance. If the simulated metrics are reproducible and translate to hardware, the array would represent a compact, high-directivity solution for 28 GHz beamforming in intelligent transportation and wireless backhaul. The use of narrow interconnects for series feeding is a standard but practical approach; however, the lack of any experimental validation or tolerance analysis substantially reduces the immediate engineering impact and reproducibility of the claimed performance.

major comments (3)
  1. [Abstract and Results] Abstract and Results section: The central performance claims (S11 better than -10 dB, narrow beamwidth, high directivity) are presented without any substrate parameters (ε_r, tan δ, thickness), exact patch dimensions, feed-line widths, inter-element spacing values, or simulation setup (solver, mesh density, boundary conditions). These omissions are load-bearing because the 0.1 mm interconnects at 28 GHz are highly sensitive to fabrication tolerances, directly affecting impedance matching and array factor.
  2. [Results and Conclusion] Results and Conclusion sections: All metrics derive exclusively from unvalidated EM simulations; no fabricated prototype, VNA measurements, or anechoic-chamber patterns are provided. At millimetre-wave frequencies, connector effects, substrate variations, and mutual coupling can degrade the reported reflection coefficient and beamwidth by several dB, undermining the claim of suitability for automotive radar and 5G backhaul.
  3. [Design] Design section: No sensitivity or Monte-Carlo analysis is included for etching tolerances on the 0.1 mm lines or for substrate permittivity variation. Such a study is required to support the assertion that the narrow beam and wide bandwidth will be maintained in practice.
minor comments (3)
  1. [Abstract] The abstract states 'reflection coefficient better than 10 dB'; this should read 'better than -10 dB' for standard convention.
  2. [Figures] Figure captions and axis labels for radiation patterns should explicitly state frequency, plane (E/H), and whether results are simulated or measured.
  3. [Introduction] Add references to standard series-fed array design equations or prior 28 GHz patch-array works to place the contribution in context.

Simulated Author's Rebuttal

3 responses · 1 unresolved

We thank the referee for the thorough and constructive review. We address each major comment point by point below, indicating revisions where appropriate. Our responses focus on improving clarity and reproducibility while remaining faithful to the simulation-based scope of the work.

read point-by-point responses

  1. Referee: [Abstract and Results] Abstract and Results section: The central performance claims (S11 better than -10 dB, narrow beamwidth, high directivity) are presented without any substrate parameters (ε_r, tan δ, thickness), exact patch dimensions, feed-line widths, inter-element spacing values, or simulation setup (solver, mesh density, boundary conditions). These omissions are load-bearing because the 0.1 mm interconnects at 28 GHz are highly sensitive to fabrication tolerances, directly affecting impedance matching and array factor.

    Authors: We agree that these parameters are essential for reproducibility and should be consolidated. The Design section describes the 0.1 mm interconnects and inter-element spacing chosen for narrow beam formation, but we will add a summary table in the revised manuscript listing all dimensions, substrate specifications, and CST Microwave Studio simulation settings (including mesh and boundary conditions) to make this information immediately accessible. revision: yes

  2. Referee: [Results and Conclusion] Results and Conclusion sections: All metrics derive exclusively from unvalidated EM simulations; no fabricated prototype, VNA measurements, or anechoic-chamber patterns are provided. At millimetre-wave frequencies, connector effects, substrate variations, and mutual coupling can degrade the reported reflection coefficient and beamwidth by several dB, undermining the claim of suitability for automotive radar and 5G backhaul.

    Authors: We acknowledge that the manuscript presents only electromagnetic simulation results and does not include fabricated prototypes or measurements. We will revise the abstract, results, and conclusion to explicitly frame the performance as simulated, add a brief discussion of expected mm-wave fabrication effects, and qualify the suitability claims accordingly. However, the work's contribution lies in the design approach and simulated metrics. revision: partial

  3. Referee: [Design] Design section: No sensitivity or Monte-Carlo analysis is included for etching tolerances on the 0.1 mm lines or for substrate permittivity variation. Such a study is required to support the assertion that the narrow beam and wide bandwidth will be maintained in practice.

    Authors: We agree that tolerance analysis strengthens the practical relevance at 28 GHz. We will add a new subsection with parametric sweeps and a basic Monte-Carlo-style variation of the 0.1 mm line widths (±0.02 mm) and substrate parameters, demonstrating the robustness of the reflection coefficient and beamwidth. revision: yes

standing simulated objections not resolved
  • Experimental validation via fabricated prototype, VNA, and anechoic chamber measurements, as no hardware was built or measured in this study.

Circularity Check

0 steps flagged

No circularity: standard simulation-based antenna design

full rationale

The manuscript describes a conventional 1x6 series-fed microstrip patch array at 28 GHz using standard EM simulation (implied by context of reflection coefficient, current distribution, and radiation patterns). No derivation chain, first-principles equations, fitted parameters presented as predictions, or self-citations are load-bearing. Performance metrics are direct simulation outputs for the chosen geometry and feed network; the central claims do not reduce to their own inputs by construction. This is the expected outcome for a design/experimental paper without mathematical modeling loops.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Only the abstract is available, so no explicit free parameters, axioms, or invented entities can be extracted from the text. The design implicitly rests on standard assumptions of microstrip antenna theory (TEM propagation, negligible surface waves, perfect conductors) that are not stated or justified here.

pith-pipeline@v0.9.0 · 5544 in / 1151 out tokens · 43146 ms · 2026-05-09T17:36:47.777430+00:00 · methodology

discussion (0)

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Reference graph

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