A compact wide‐band antipodal Vivaldi antenna (AVA) is designed in this work. First, the traditional exponentially tapered edge of the radiator is replaced by an arc curve that makes the AVA compact. Second, the AVA is loaded with a “director” and a “convex lens” that improve its high‐frequency performance. The proposed antenna is fabricated and its dimensions measured. It occupies a small volume of 34 × 16 × 0.8 mm³ and provides an operating frequency range from 3.01 to 10.6 GHz with a higher gain in the low frequency region than that of reference antennas. The measured results perfectly coincide with the simulated ones, which demonstrates the feasibility of the novel AVA design.

Existence states of f-shell electrons in Ca-Mt is calculatedviaDFT with 2D-CA techniques. Reasons of f-shell electrons influencing on electronic and optical properties are discussed. Electronic transitions are systematically analyzed.

A uniplanar quasi-isotropic folded dipole is proposed by using a hybrid genetic algorithm and particle swarm optimization (GA-PSO) algorithm. The proposed antenna is evolved from a half-wave dipole, where the dipole is folded to achieve a pair of out-of-phase line sources and an orthogonal line source, thereby obtaining a quasi-isotropic radiation pattern. Based on GA-PSO algorithm, the bending position is optimized for the minimum gain difference. For demonstration, the dipole prototype operating at 915 MHz is designed and fabricated in which a parallel transmission line with comb-like structure is adopted to achieve good impedance matching. The measured result shows a gain difference of 2.81 dB, and the simulated value is 0.34 dB. Compared with other quasi-isotropic antennas, the proposed antenna has merits of simple structure, low gain difference and uniplanar structure.

In this paper, a new U-shaped ring spoof surface plasmon polariton (SSPP) structure is proposed as part of a bandpass filter (BPF) combined with short-circuited stubs (SCSs). The U-shaped ring unit offers miniaturization and multiple adjustable parameters. Furthermore, the lower and upper cutoff frequencies of the passband for the BPF can be adjusted by modifying the structural parameters of the SSPP units and SCSs, respectively. To validate the design, a prototype filter was first created with a frequency range of 2 to 3.7 GHz for the passband and an extended stopband that reached up to 15 GHz. On the basis of the designed BPF, a tri-band filter was realized by introducing multiple transmission zeros by loading multiple open-circuited stubs (OCSs) onto the transmission portion of SSPPs. The center frequencies of the three passbands were 1.20 GHz, 2.03 GHz, and 2.96 GHz, respectively. At the same time, the upper stopband rejection reached up to 12 GHz with an attenuation of −30 dB, about 10 times the center frequency of the first passband. The experimental results demonstrate a strong correlation between the measured and simulated outcomes, thereby validating the proposed structure and design methodology. Notably, the filter measures only 0.38λg × 0.13λg, highlighting its compact size as a significant advantage.