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Low-Profile Differential-Fed Flat-Top Beam Antenna Design Based on Independent Regional Tailoring of High-Order Mode

Li, Jiawang LU orcid ; Ding, Zhendong ; Wu, Fan and Tong, Kin Fai (2026) In IEEE Transactions on Antennas and Propagation
Abstract

This paper presents a novel low-profile, single-layer, differentially-fed microstrip antenna with a flat-top beam (FTB). By incorporating a central hexagonal slot together with four elongated slots and two short slots, the proposed antenna tailors high-order modes to achieve the desired radiation characteristics. By analyzing the electric field, the distribution in various regions is decomposed and synthesized to generate a two-dimensional flat-top beam in both the E-plane and H-plane. The evolution of the antenna structure is systematically analyzed, showing how specific slot arrangements and differential feeding lead to wide beamwidth and low sidelobes. Prototypes were fabricated and measured, demonstrating a -10 dB impedance... (More)

This paper presents a novel low-profile, single-layer, differentially-fed microstrip antenna with a flat-top beam (FTB). By incorporating a central hexagonal slot together with four elongated slots and two short slots, the proposed antenna tailors high-order modes to achieve the desired radiation characteristics. By analyzing the electric field, the distribution in various regions is decomposed and synthesized to generate a two-dimensional flat-top beam in both the E-plane and H-plane. The evolution of the antenna structure is systematically analyzed, showing how specific slot arrangements and differential feeding lead to wide beamwidth and low sidelobes. Prototypes were fabricated and measured, demonstrating a -10 dB impedance bandwidth of 2.0% (3.46–3.53 GHz), 3 dB beamwidths of 84° in E-plane and 80° in H-plane, a flat in-band average gain of 6.89 dBi, and a cross-polarization suppression above 39 dB. Compared with conventional flat-top beam antenna arrays and dielectric resonator structures, this design achieves superior flat-top effect with 3 dB beamwidth 84°/80° on the E/H plane, low profile (0.02 λo), low cost, and straightforward fabrication, without requiring complex feeding networks.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
differential-fed, Flat-top beam, high-order mode, low-profile microstrip design, wireless power transmission
in
IEEE Transactions on Antennas and Propagation
publisher
IEEE - Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:105028908960
ISSN
0018-926X
DOI
10.1109/TAP.2026.3656584
language
English
LU publication?
yes
id
87bda307-1b89-44b5-9488-8fe13df9e6a7
date added to LUP
2026-02-25 09:55:23
date last changed
2026-02-25 09:55:33
@article{87bda307-1b89-44b5-9488-8fe13df9e6a7,
  abstract     = {{<p>This paper presents a novel low-profile, single-layer, differentially-fed microstrip antenna with a flat-top beam (FTB). By incorporating a central hexagonal slot together with four elongated slots and two short slots, the proposed antenna tailors high-order modes to achieve the desired radiation characteristics. By analyzing the electric field, the distribution in various regions is decomposed and synthesized to generate a two-dimensional flat-top beam in both the E-plane and H-plane. The evolution of the antenna structure is systematically analyzed, showing how specific slot arrangements and differential feeding lead to wide beamwidth and low sidelobes. Prototypes were fabricated and measured, demonstrating a -10 dB impedance bandwidth of 2.0% (3.46–3.53 GHz), 3 dB beamwidths of 84° in E-plane and 80° in H-plane, a flat in-band average gain of 6.89 dBi, and a cross-polarization suppression above 39 dB. Compared with conventional flat-top beam antenna arrays and dielectric resonator structures, this design achieves superior flat-top effect with 3 dB beamwidth 84°/80° on the E/H plane, low profile (0.02 λ<sub>o</sub>), low cost, and straightforward fabrication, without requiring complex feeding networks.</p>}},
  author       = {{Li, Jiawang and Ding, Zhendong and Wu, Fan and Tong, Kin Fai}},
  issn         = {{0018-926X}},
  keywords     = {{differential-fed; Flat-top beam; high-order mode; low-profile microstrip design; wireless power transmission}},
  language     = {{eng}},
  publisher    = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}},
  series       = {{IEEE Transactions on Antennas and Propagation}},
  title        = {{Low-Profile Differential-Fed Flat-Top Beam Antenna Design Based on Independent Regional Tailoring of High-Order Mode}},
  url          = {{http://dx.doi.org/10.1109/TAP.2026.3656584}},
  doi          = {{10.1109/TAP.2026.3656584}},
  year         = {{2026}},
}