Inkjet printing technology is widely used in the manufacture of conformal structures, such as load-bearing antennas or frequency-selective surface radomes. It is particularly promising for preparing conductive patterns on non-developable surfaces. Existing printing technologies employ a single nozzle and a five-axis linkage technique for printing, which is time-consuming. In this study, a conformal plane printing technology based on the arrayed nozzle was developed to prepare conductive patterns on a non-developable surface. The technique actualizes fast printing of passive circuits on a conformal surface, such as a microstrip antenna. Compared to printing techniques employing a single nozzle, the proposed method greatly improves the printing efficiency on conformal surfaces. Specifically, we first developed a model for the driver waveforms and the printing injection parameters via simulation. Subsequently, the accuracy of the computational fluid dynamic simulation results was validated by comparing them with the experimental measurements of droplet trajectory captured using a camera. Next, a droplet spreading model was established, considering energy conservation principles. Finally, a conformal surface printing technology using arrayed nozzles was developed based on the injection parameter and droplet spreading models. The effectiveness and feasibility of the proposed printing method were further validated via simulation and experimental tests of return loss.

With the advent of wearable communication devices, microstrip antennas have developed multiple applications due to their ultra-low-profile properties. Therefore, it is essential to analyze the problem of frequency shift and impedance mismatch when the antenna is bent. For the case of a rectangular patch antenna E-plane bent on the cylindrical surface, (1) this paper introduces the effective dielectric constant into the cavity model, which can accurately predict the resonance frequency of the antenna, and (2) according to the equivalent circuit model of the antenna resonance mode, the lumped element parameters are calculated based on the above effective dielectric constant, so that impedance characteristics and the S-parameter matching the port can be quickly constructed. From the perspective of circuit frequency characteristics, it explains the change in the transmission performance of the curved antenna. The experimental results show that the maximum difference between the experimental and theoretical calculation frequencies is less than 1%. These results verify the validity and applicability of the theory in the analysis of ultra-low-profile patch antennas and wearable electronic communication devices. It provides a theoretical basis for the fast impedance matching of patch antennas under different working conditions.

The interaction between structural component flexibility and the closed-loop servo system primarily determines a large reflector antenna pointing system’s performance; this is especially true for antennas with a low natural frequency. Because of difficulty and high manufacturing costs of the radome, large antennas usually operate under open-air atmospheres. Therefore, large antennas’ pointing performance can be severely influenced by wind disturbances, which can lead to reflector deflection and deformation. Accordingly, this brief has been conducted to determine how to inhibit reflector deflection in order to improve pointing accuracy. Based on a pointing control-oriented model (PCOM) which includes a dynamic model for estimating the servo error and the deformation of the structure caused by wind, this brief proposes a method for overcoming wind disturbance to improve pointing accuracy by evaluating the mode of vibration that influences the most significant beam pointing. First, a dynamic PCOM was established. Second, an antenna pointing controller was designed based on a linear-quadratic-Gaussian approach. Finally, a series of tests and analyses of a 7.3-m Ka-band antenna was conducted; the results show that the maximum pointing error was reduced from 0.0103° to 0.0024° compared with the error experienced with a traditional proportional–integral–derivative controller.

Piezoelectric print-heads (PPHs) are used with a variety of fluid materials with specific functions. Thus, the volume flow rate of the fluid at the nozzle determines the formation process of droplets, which is used to design the drive waveform of the PPH, control the volume flow rate at the nozzle, and effectively improve droplet deposition quality. In this study, based on the iterative learning and the equivalent circuit model of the PPHs, we proposed a waveform design method to control the volume flow rate at the nozzle. Experimental results show that the proposed method can accurately control the volume flow of the fluid at the nozzle. To verify the practical application value of the proposed method, we designed two drive waveforms to suppress residual vibration and produce smaller droplets. The results are exceptional, indicating that the proposed method has good practical application value.

The pointing error caused by the structural deformation of large reflector antennas has become the most challenging problem of antenna servo control. Especially with the increase of the antenna diameter and the working frequency, environmental loads not only make the structure deformation more obvious, but also make the pointing accuracy influenced by deformation more sensitive. In order to solve this problem, accurately estimating the pointing error caused by the structural deformation is the key. Based on the dynamic model of antenna structure and the analyzing model of pointing error, using the displacement information of sampling points on reflector, this paper proposes a correction method to achieve the purpose of accurately estimating the pointing error caused by the structural deformation. Using a 7.3‐m Ka band antenna, the results show that the antenna maximum pointing error in theoretical model calculation is 0.0041° at 10m/s wind speed condition; however, the corrected pointing error would be about 0.0054° with considering the modeling error. After compensating the controller, the pointing error could be reduced to only 0.0008° and the performance of antenna pointing was improved.

This work presents an amplitude-phase-based interval analysis (IA-AP) method of radome electromagnetic (EM) performance under thickness errors and its application in radome robust design. The amplitude and phase intervals of radome transmission coefficient, which form a sector interval in the complex plane, are deduced to model more accurately the effect of thickness errors. The power pattern is then obtained based on the convex polygon approximation of the sector region and the Minkowski sum method. Compared with the real-imaginary-parts-based interval analysis method (IA-RI), the proposed method can yield much narrower power pattern interval, and the EM performance intervals are tightened by 42%-70%. Using the proposed IA-AP method, it is shown that radome design oriented towards both good and robust EM performance is possible.