Compact line source generator for feeding continuous transverse stub arrays

Based on a substrate integrated lens (SIL), a compact line source generator (LSG) for feeding continuous transverse stub (CTS) arrays with linear-polarized (LP) beam scanning and dual-polarized (DP) operations is presented in this paper. The SIL consists of metamaterial cells with different sizes being arranged as concentric annulus and is printed on the center surface of two substrate layers. The SIL can convert the cylindrical wave generated by the feed probe of SIW-horn to the planar wave for feeding the CTS array. This rotationally symmetric SIL can be used conveniently to design LSG for feeding CTS arrays with the continuous beam scanning and DP operations, which has been verified by the fabrications and measurements. By simply rotating the SIW-horn along the edge of SIL, the 10-element LP-CTS array obtains a measured beam scanning range of ±35° with the highest gain of 20.6 dBi. By setting two orthogonal SIW-horns at the edge of the proposed SIL, the nine-element DP-CTS array with orthogonal radiation stubs is excited. The DP array obtains the gain of 20.3 dBi at the center frequency with the isolation of 28 dB and the cross-polarization level <−25 dB.

Four-Quadrant Riemann Problem for a 2×2 System Involving Delta Shock

In this paper, a four-quadrant Riemann problem for a 2×2 system of hyperbolic conservation laws is considered in the case of delta shock appearing at the initial discontinuity. We also remove the restriction in that there is only one planar wave at each initial discontinuity. We include the existence of two elementary waves at each initial discontinuity and classify 14 topologically distinct solutions. For each case, we construct an analytic solution and compute the numerical solution.

MEASURES OF THE BASIS EFFICIENCY IN THE INTERNAL ROTATION PROBLEM

Рассмотрено понятие вариационного предела при численном решении торсионного уравнения Шрёдингера и определены значения энергий состояний и переходов между ними на вариационном пределе в зависимости от размера базиса. На большом числе модельных потенциалов показано, что количество достоверно вычисляемых уровней линейно зависит от числа базисных функций. Данное число уровней (номер наибольшего достоверного состояния) рекомендовано в качестве меры эффективности базиса. Для базиса плоских волн найдено, что коэффициент углового наклона линейной зависимости составляет ≈ 1,03. Definition of the variational limit for the Schrodinger torsion equation solution was considered. Energies of levels and transitions at the variational limits were calculated for different basis sets. With many modeling potentials it was shown that the quantity of reliable calculated levels linearly depends on the number of the basis functions. This number (the number of the maximum reliable state) was recommended as a measure of the basis efficiency. The slope of the straight line for the planar wave basis dependence is approximately equal to 1,03.

Dual Frequency CPW Fractal Antenna for Wireless Applications

A Co-planar wave guide fed rectangular ring antenna for WiFi and 5G applications is proposed in this paper. The operating frequency of the antenna is centered at two frequencies i.e 2.52GHz and 3.65GHz which are in S-band frequency spectrum. The main radiator is rectangular ring for whose inner corners are smoothed. The similar structure of the main radiator is etched from the ground plane making the proposed technique a fractal. For the proposed antenna FR4 laminate is used as substrate and a line feed is used to provide excitation. To achieve the high wide bandwidth we have implemented the fractal technique. The antenna size is 60mm×60mm×1.6mm and is radiating in the frequency range of 2.27GHz to 2.67GHz covering 400MHz of bandwidth and 3.5GHz to 3.82GHz covering 320MHz of bandwidth.