To meet the demand for multifunctional antennas in shipborne communication systems, this paper proposes a novel high gain four-beam reconfigurable patch antenna based on the Yagi antenna.

The proposed antenna is composed of four symmetrical sector elements, with four PIN diodes loaded between the central patch and the sector components. These PIN diodes are used to control the radiation pattern by switching their on/off states, allowing the antenna to achieve four distinct directional patterns. Additionally, arc-shaped parasitic units are incorporated as reflectors or directors to enhance the antenna's gain and suppress sidelobes. The antenna is fabricated on a single-layer PTFE substrate with a dielectric constant of 2.2 and a loss tangent of 0.001, with overall dimensions of 80 mm × 80 mm × 4 mm. The design process involved optimizing various parameters, such as the radius of the sector patches (R1) and the spacing between the parasitic units and the sector patches (D1), to achieve the desired performance. The antenna's performance was evaluated through both simulation and experimental testing, with detailed analysis of its radiation patterns, gain, and impedance characteristics.

Experimental results demonstrate that the antenna can achieve beam pointing at four specific azimuth angles (45°, 135°, 225°, and 315°) across four operating modes. Within the frequency range of 5.47 to 6.05 GHz, the antenna exhibits a high average gain of 7.46 dBi, with a measured impedance bandwidth of 10.07%. The measured gain is consistent across all four modes, with a maximum gain of 8.68 dBi observed within the operating band. The introduction of parasitic elements significantly enhances the antenna's directional radiation pattern, reducing sidelobes and improving gain. The optimized antenna demonstrates excellent impedance matching and radiation characteristics, with the measured results closely matching the simulated performance.

The proposed antenna has the advantages of high gain, low profile and simple control. Its radiation direction can be dynamically adjusted according to the communication needs of ships in order to reduce signal interference and improve communication quality.

In order to solve the installation space limitations of shipboard communication devices and the low communication efficiency of shipborne antennas due to interference by signals from other equipment, this paper proposes a miniaturized and high-isolation compact MIMO antenna that can cover a wide frequency band.

The antenna unit is based on an elliptical patch that expands into the final octagonal structure by rotational translation; the four units are placed orthogonally on the dielectric substrate to improve the data transmission rate and channel capacity of the antenna; and adding a square metal patch to the back of the antenna improves the isolation between antenna units, while the overall size of the antenna is only 32 mm×32 mm×1.6 mm.

The results show that the impedance bandwidth of S₁₁ ≤ −10 dB is measured as 3.4−10 GHz; the S₃₁ of the antenna drops from about −15 dB to less than −22 dB with a lowest point of −46 dB, improving isolation by 31 dB; and the antenna envelope correlation coefficient is less than 0.05, the diversity gain is greater than 9.7 dB and the highest gain of the antenna can reach 4.5 dBi.

On the basis of miniaturization, the MIMO antenna can cover a wide frequency band and has a high degree of isolation, strong anti-interference ability and high channel capacity, enabling it to be widely used in shipborne wireless communication equipment.

In order to effectively broaden the beam width of the 3 dB axis ratio of a Beidou antenna, this paper proposes a slotted laminated microstrip patch antenna loaded with parasitic elements.

The Beidou dual frequency band feature is realized through a two-layer substrate structure. The bandwidth is widened by slotting. Circular polarized radiation is achieved by cutting corners at the edge of the patch. At the same time, L-shaped parasitic elements are loaded around the patch to broaden the 3 dB axial ratio beam width of the antenna.

The measured and simulated results are in good agreement. The relative bandwidths of the antenna in the Beidou B1 and B2 bands are 3% and 7.5%. The beam width of the 3 dB axis ratio can reach 180° and 176°, and the maximum gain can reach 6 dBi. In the Beidou receiver test, the number of antenna satellites can reach more than 17, and the positioning accuracy is within meters.

This paper proposes and validates a high-precision positioning dual band Beidou navigation antenna with wide axis ratio beam width. The results can provide references for the design of small Beidou navigation antennas.

In order to effectively improve the gain and bandwidth of antennae, a low-cost and tunable stacked microstrip antenna based on ferrite is proposed for WLAN.

By adopting magnetic ferrite as the substrate of the microstrip antenna, its performance and response to external electromagnetic fields can be adjusted. Its directional characteristics can also be tuned via a laminated substrate structure to improve the gain. By arranging elliptical parasitic patches in a clockwise direction around the metal patch, the bandwidth characteristics of the antenna can be effectively improved.

The measured data and simulation results are in good agreement, covering the entire frequency band range of 5.15–5.35 GHz in the WLAN system. According to the test results, the relative bandwidth of the antenna in the C-band is 19% and its highest gain is 9.15 dBi.

The results of this study can provide references for the design of miniaturized and magnetically tunable antennas.