Search

This letter introduces the design of a highly efficient reconfigurable C/X dual‐band power amplifier (PA). Conventional dual‐band designs connect two amplifier branches for each band by a switch, whose transmitting losses will limit the efficiency of the PA. In alternative to the switching solution, the authors propose a novel design method using two branches of output matching networks (OMN) which the 5–6 and 8–12 GHz branch acting as active loads for each other, respectively. The band‐pass OMNs are applied, and parts of the passive matching components are replaced by transistors for channel selection. The proposed design has been simulated, implemented, and measured. The experimental results demonstrate a power added efficiency (PAE) of 45% at a pulsed output power (Pout) of 42 dBm in 5–6 GHz while a PAE greater than 39% at 42 dBm Pout in 8–12 GHz. Moreover, the second and third harmonics of both operating bands are compressed to −35 and −40 dBc, respectively. The proposed design technique addresses the challenges of low‐efficiency and lower‐band harmonic suppression in traditional dual‐band designs, making it suitable for application in next‐generation satellite communication and remote sensing systems. [ABSTRACT FROM AUTHOR]

In this paper, titanium dioxide methylene blue molecularly imprinted polymer (TiO2-MB-MIP) was prepared by using MB-MIP as supported carrier. Through the study of its adsorption performance and photodegradability, it was found that the prepared TiO2-MB-MIP has both the adsorption capacity and the photodegradation capacity on MB. The static adsorption experiment shows that its adsorption and photodegradation capacity can reach 1202.1 mg ⋅ g − 1 when the original concentration of MB is 5.0 mg ⋅ mL − 1 . In addition, the degradation ability of the material in MB aqueous solutions was studied under varying light conditions. By analyzing the nitrogen and carbon content in the adsorbed solutions, the degradation process was found that the carbon and heteroatoms nitrogen in MB can be degraded to CO2, and NH 4 + or NO 3 − , respectively. The adsorption isotherm thermodynamics and kinetics model study found that the adsorption process conforms to the Langmuir isotherm equation and the quasi-secondary kinetic model, indicating that the adsorption is basically monolayer adsorption and the adsorption process is the chemical rate control step. The TiO2-MB-MIP can be used to protect our environment by treating pigment wastewater efficiently. [ABSTRACT FROM AUTHOR]

In this article, the 3D‐printed dielectric lens is proposed to generate Bessel beam in millimeter‐wave band. The dielectric lens is made of many square unit cells with the side length of a half wavelength. The unit cells with different thicknesses generate different insertion phase shift to the transmitted millimeter wave. The insertion phase distribution of the lens is calculated by comparing the phase distributions of the incident Gaussian beam and the desired output Bessel beam. Three types of lenses are simulated and fabricated using 3D printing technology with Nylon. The measured magnitude and phase distributions of zero‐order Bessel beam agree with the simulated results very well and the measured phase distributions of the first‐order Bessel beam carry orbital angular momentum. [ABSTRACT FROM AUTHOR]