Aiming at problems with shipboard wireless communication equipment such as its compact layout, limited space, and serious electromagnetic interference between devices, a miniaturized ultra-wideband multiple-input multiple-output (UWB-MIMO) antenna with high isolation is proposed.

The antenna's bandwidth is extended and its return loss effectively increased by cutting the angle design and etching an offset triangle hole. A complementary split-ring resonator (CSRR) is used to enhance the isolation and add resonant frequency points to achieve ultra-wideband coverage. At the same time, a porous parasitic patch is loaded on the floor to effectively reduce coupling at high frequency.

The simulation and measured results show that the overall size of the antenna is highly miniaturized at only 28 mm × 17 mm × 1.6 mm, while it has a working bandwidth of 4.6–10.9 GHz, relative bandwidth of 81.3%, frequency band isolation degree higher than 15 dB (with a maximum of 30.7 dB), envelope correlation coefficient of < 0.008, and gain in the whole band of >2 dB.

The designed MIMO antenna is compact in size and possesses ultra-wideband coverage and good omnidirectional characteristics, enabling it to be widely used in miniaturized shipborne wireless communication equipment.

This paper discusses the damage characteristics of gallium nitride (GaN)-based low-noise amplifiers (LNA) under high power microwave (HPM) pulses.

The effect of HPM pulses with different pulse widths and duty cycles was studied to investigate the changes in DC and RF parameters of GaN LNA. In the experiment, the threshold power of the device was determined through continuous wave and microwave pulse testing with different pulse widths and duty cycles. At the same time, in order to better determine the damage area and the physical mechanism of LNA failure, the surface and internal areas of the chip were examined using a microscope and dual-beam FIB （focused ion beam ） devices after the chip was unpackaged.

The experimental results show that when the GaN LNA was exposed to sufficient microwave pulse power with a pulse width of 30 ns, a rising edge of 18 ns, and a falling edge of 18 ns with a period of 2 ms, the gain of the LNA decreased from 23.67 dBm to −8.91 dB, the noise factor increases from 1.59 dB to 18.13 dB, and the LNA output waveform was severely compressed. The damage was primarily caused by the formation of a micro-current channel at the gate from HMP exposure, leading to drain overcurrent and permanent device damage.

The study on the damage effects of GaN LNA under HMP pulse conditions provides important reference value for further understanding the impact of HMP pulses on GaN LNA and for improving its robustness.

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.

With increasing congestion and interference facing shipborne wireless communication equipment, it is urgent for antennae functions to be reconstructed. This study proposes a microstrip Quasi-Yagi antenna with a continuously reconfigurable cross-band frequency function.

First, PIN diodes are loaded on the quasi-Yagi antenna, and multi-band multi-mode switching is realized by controlling turning the diodes on/off. Second, by attaching snowflake split-ring resonator (SRR), the antenna gains two stable frequency resonance points and a stable radiation azimuth.

According to the simulation and measurement results, the antenna realizes frequency reconfiguration in the C-band (5.77–7.10 GHz and 7.40–7.56 GHz) and X-band (8.33–8.64 GHz and 8.76–9.27 GHz). Its radiation pattern can stably point in the direction of capacitive loading conduction, with gain above 5.7 dBi at each frequency and an average 3 dB beamwidth value of 102°.

By loading PIN diodes on the antenna and attaching a snowflake SRR, cross-band frequency becomes frequency reconfigurable, and beam deflection with low error is achieved, thereby improving the spectral utilization of ship systems and avoiding coupling interference between multiple antennae.