Private 5G (P5G) networks are being deployed in industrial, campus, and enterprise environments where demands for secure, low-latency, and high-reliability wireless connectivity are paramount—supporting applications such as smart manufacturing, autonomous logistics, and mission-critical IoT. South Korea’s dedicated allocation of the 4.7 GHz band for P5G reflects its suitability for combining moderate coverage and high capacity. Essential to P5G’s performance is MIMO technology, which improves link capacity and resilience through spatial multiplexing and diversity. Realizing these benefits requires antenna subsystems that offer wide angular coverage, robust polarization isolation, and the ability to support both TX and RX operations with minimal interference [1]. A higher number of antennas can enhance data capacity in MIMO systems. However, data transmission and reception remain limited to each antenna’s beam coverage. To serve wide areas, base stations typically adopt sectorized antennas, where multiple panels each cover a narrow region, as shown in Fig. 1(a). In practice, two 65° sector antennas are commonly deployed to achieve approximately 130° coverage, which is a standard field requirement. This work focuses on eliminating one of these two sector antennas, allowing a single panel to cover the entire 130° sector, as illustrated in Fig. 1(b). This approach maintains the same total coverage while reducing the number of antenna panels, resulting in a simpler and more cost-effective base-station configuration. Conventional P5G base stations rely on dual- or multi-sector narrow-beam antennas (approximately 65° per sector) to achieve wide coverage, but this increases system cost, hardware complexity, physical footprint, and calibration burden [2]. In contrast, a wide-beamwidth antenna (half-power beamwidth [HPBW] >120°) can function as a single-sector radiator, enabling cost-effective P5G deployment without additional local antenna modules. If these are implemented with dual linear polarization (LP), they can foster compact MIMO arrays by facilitating parallel, isolated TX/RX streams while minimizing mutual coupling and avoiding additional RF leakage cancellation circuits. Although the leakage cancellation circuits can effectively improve isolation characteristics, they add complexity, insertion loss, and physical bulk, making them impractical for integrated MIMO antenna modules operating in the 4.7 GHz band [2–5].

To obtain wide beam antenna characteristics, various architectures have been investigated. Magneto-electric dipole designs, for example, yield symmetric patterns (100°–120° HPBW) but often rely on stacked or volumetric structures [6]. Planar microstrip elements using capacitive fences or slots achieve beam widening and isolation with printed circuit board (PCB)-level simplicity, though with limited symmetry or frequency stability. Crossed-dipole antennas with parasitic directors have demonstrated exceptional beamwidths (>150° and approx. 168° in orthogonal planes) but require precise element tuning to optimize performance [7]. Also, wide-angle scanning phased arrays operating across 4.4–5.0 GHz have achieved ±60° scan using wide beam unit cells at the cost of complex feeding systems and larger footprint [8]. Furthermore, planar antenna structures have been proposed that extend beamwidth significantly while maintaining a low profile [9–15]. These planar designs demonstrate wide angular illumination in a single radiator and allow array expansion for wide angle scanning performances, but they support only single LP, limiting their immediate applicability in dual-polarized MIMO systems.

Therefore, considering these challenges, this paper introduces a dual LP planar antenna element tailored to the aligned band of Korea’s 4.7 GHz P5G allocation. The proposed design achieves an HPBW exceeding 130°, enabling seamless single sector coverage as shown in Fig. 1(b), while supporting dual slanted LP with high isolation to realize a compact MIMO configuration as depicted in Fig. 2. In addition, the proposed configuration provides structural symmetry, planar implementation, and straightforward integration with active modules, which would be difficult to achieve with most existing wideband antenna geometries. The fully planar, PCB-compatible structure can promote scalable and cost-effective deployment in next-generation P5G base stations.

The proposed dual LP patch antenna employs orthogonally arranged capacitive-coupling feeds positioned along the lateral and lower edges of the primary radiator, allowing separate excitation paths for horizontal polarization (HP) and vertical polarization (VP). To extend the HPBW for both polarizations, a modified implementation of a DGL configuration—originally introduced in [13] is integrated into the antenna structure. The following section presents a comprehensive theoretical framework detailing the antenna’s operating principles, drawing upon transmission line modeling and cavity model interpretations [16], as well as key electromagnetic concepts underlying the DGL-based beam shaping mechanism.

The proposed antenna was fabricated using a standard PCB process, and photographs of the top and bottom views are shown in Fig. 8(a). The overall antenna size, including the ground plane and the DGL, is 67 mm × 67 mm × 4.74 mm, ensuring a compact profile suitable for potential P5G MIMO applications. The reflection coefficients of the HP and VP ports were measured, as shown in Fig. 8(b). The measured 10-dB impedance bandwidth was approximately 275 MHz, covering the operation band of 4.58–4.85 GHz, which is similar with the simulated results. Furthermore, the measured port-to-port isolation exceeded 25 dB across the operating bandwidth, confirming excellent isolation performance. Minor deviations between the measured and simulated S-parameters were observed, primarily due to fabrication tolerances and assembly variations, including the RF connector. However, the overall matching and isolation trends match well with the simulation, validating the robustness of the proposed design. Radiation pattern measurements were conducted in a microwave anechoic chamber, as depicted in Fig. 8(c).

In Fig. 9(a)–9(h), both the co-polarization and cross-polarization radiation patterns are presented for the HP and VP excitations across 4.6–4.9 GHz. Across the measured band, both polarizations exhibited stable radiation patterns with HPBW ranging from 131° to 138°, which is in good agreement with the simulated results. The beamwidth enhancement observed in simulation is clearly validated through these measurements, confirming the effectiveness of the DGL-based configuration in enabling wide-angle radiation. Also, the measured peak gains were 2.6 dBi, 3.2 dBi, 3.9 dBi, and 2.5 dBi at 4.6 GHz, 4.7 GHz, 4.8 GHz, and 4.9 GHz, respectively, while the simulated peak gains at these frequencies were 2.6 dBi, 3.4 dBi, 3.5 dBi, and 2.5 dBi, respectively. The comparison between the simulated and measured radiation patterns confirms that the proposed DGL structure effectively broadens the radiation beamwidth for dual polarization.

However, minor discrepancies between the simulation and measurement were observed at 4.9 GHz. This was mainly attributed to 3D-printed fixture used to secure the antenna during measurement, as shown in Fig. 8(c). The fixture introduced additional scattering and slightly perturbed the DGL structure, particularly at the upper edge of the operating band, leading to partial field distortion and a dip in the main beam center. Additionally, dielectric loss increases and small variations in effective permittivity at higher frequencies can further reduce radiation efficiency. These effects collectively lead to partial field dispersion and reduced gain in the main lobe direction. To validate this effect, a 3D electromagnetic simulation was additionally performed with the antenna fixture included, as shown in Fig. 10. The simulated radiation pattern with the fixture exhibits a gain reduction at the center compared to the radiation pattern without the fixture. Despite these factors, the measured cross-polarization discrimination ranges from 25.2 dB to 32.9 dB across the operation band, and cross-polarization components remain consistently suppressed, as predicted by simulation, indicating high polarization purity of the proposed antenna. The angular phase transformation induced by the DGL structure contributes to spatial beam broadening and improves sector coverage while maintaining dual-polarization characteristics. These experimental results demonstrate that the DGL design principle observed in simulation can be reliably implemented in practical fabricated prototypes.

Lastly, Table 1 summarizes the measured performance of the proposed antenna compared with other recent designs. Compared with [9], [11] and [17], which are single-polarized antennas, the proposed DGL-based design offers the clear advantage of dual polarization, enabling more efficient integration into MIMO communication systems. In comparison with [18–20], the proposed antenna achieves a wider half-power beamwidth (131°) while maintaining a planar structure with reduced height (0.07λ₀). This compact and low-profile configuration facilitates seamless integration into P5G MIMO base stations, providing wide-angle coverage and robust polarization purity for the cost-effective solution.

This work presented a compact dual LP wide beamwidth antenna element optimized for P5G MIMO applications in Korea’s 4.7 GHz band. To overcome the limitations of reference sector antennas, a DGL was employed to refract radiated energy outward through angular phase transformation, significantly enhancing the HPBW without compromising gain or polarization performance. The proposed antenna achieved the measured HPBW exceeding 131° in both polarizations, along with high isolation (>28.6 dB) and cross-polarization discrimination (>25.2 dB), as confirmed through simulation and measurement. These results validate the proposed design as a highly effective solution for single-sector wide coverage and dual-polarized MIMO integration in next-generation P5G base station architectures. In addition, its planar structure and compatibility with standard PCB processes facilitate seamless integration with active modules, enabling compact and high-density deployments in next-generation communication systems. Future work will focus on large-scale MIMO implementation, where the proposed wide beam element can reduce the number of antenna units required for full coverage, simplify base station architecture, and eliminate the need for sectorization.