[신간안내] Computational Electrodynamics (the finite difference time - domain method)

An optimized three-dimensional one-step leapfrog finite-difference time-domain (FDTD) method has been investigated, which is with a weakly conditional stability (WCS) to reduce numerical dispersion further. By introducing the artificial anisotropy parameters in a cross-correspondence manner, the phase velocity error is effectively limited without additional computational time and memory cost. An auxiliary field variable is adopted to simplify the iterative formulae with few additional processes, and the same stability has been validated between methods of conventional leapfrog WCS-FDTD and ourselves. Moreover, much lower numerical dispersion is shown to withstand larger Courant–Friedrich–Levy number under the same error condition. To verify our method efficiently, a newly designed hollow dielectric resonator antenna (DRA), instead of a solid one, is conducted effective calculation. Furthermore, two forms of four-element arrays have been developed with the DRA element above, and a T-shaped power divider is designed as a fed network and subjected to calculations and experimental analyses. Reflection coefficients and radiation patterns are shown the effectiveness of both DRA and arrays. The most noteworthy aspect is that our low-dispersion WCS-FDTD scheme can be effectively simulated the hollow DRA and arrays, and with excellent performance in terms of memory occupation, calculation accuracy, and efficiency.

Low-Dispersion Leapfrog WCS-FDTD With Artificial Anisotropy Parameters and Simulation of Hollow Dielectric Resonator Antenna Array

The latest 5G technology is the one which has the capacity and power for very high speed data communication in order to fulfil the requirements for robotics, live events broadcasting, high definition streaming of the videos and autonomous driving. The wide-band antennas with high gain have taken place of conventional narrow bandwidth antennas having low gain since they are now needed for reliable 5G wireless communication. In this paper we have proposed an L-slot wideband 5G antenna for 5G wideband applications resonating at 39 GHz frequency band. The antenna has been designed on a 0.5 mm thick FR-4 substrate, having dielectric constant of 4.3. The proposed antenna has simulated S11 of -29.057 dB and realized gain of 4.142 dB for 39 GHz. In addition, the VSWR value obtained is 1.073 dB, which is acceptable for its future use. Overall size of the antenna is mm × 4.8 mm × 0.5 mm. CST Microwave Studio is the software which has been used to simulate the proposed antenna.

Design and Analysis of a 5G Wide Band Antenna for Future Mobile Applications

In this letter, a dual-band interleaved base station antenna array with self-decoupling characteristic is studied. The low-band antenna radiator along with its feeding baluns can be considered as compensation and partition structures for the high-band (HB) antennas. The measured co- and cross-polarized in-band isolations between the HB subarrays are enhanced to > 24.6 dB and > 29.3 dB, respectively, without introducing extra decoupling layer. The HB radiation performances are recovered, exhibiting good capability of crossband scattering suppression. The decoupling principles are analyzed and explained.

Dual-Band Base Station Antenna Array Using the Low-Band Antenna as Parasitic Decoupler

An axial mode solid dielectric helical antenna (DHA) has been proposed, which is fabricated by using the 3-D printing technique. Fed manners of this antenna have been studied, including conformal coaxial probe and conformal metal strip line. The operating mode of dielectric helix has been analyzed in detail. Circular polarization is achieved by choosing appropriate sizes of the dielectric helix. Furthermore, a miniaturized axial mode DHA with deployable property is implemented. Measured results indicate that the proposed antenna has good radiation performance, such as circular polarization, high gain, and high radiation efficiency. Specially, the radiation patterns of the DHA have good symmetry in the 2 dB axial ratio range. The significant advantage of miniaturized DHA is light in weight, which is only 2.7% of the weight of a metal helical antenna with similar radiation characteristics. The antenna is a good candidate in wireless communication system. 

Investigation of Axial Mode Dielectric Helical Antenna

To model the object with concave and convex surfaces accurately, an economical conformal subgridding scheme is proposed in this article. Its double conforming procedure with coarse grid (CG) and fine grid (FG) guarantees the modeling accuracy. Fast linear interpolation effectively exchanges electromagnetic fields information on the interface between grids of two sizes. One-step leapfrog alternating direction implicit (ADI) finite-difference time-domain (FDTD) method overcomes the Courant stability condition in FG region; meanwhile, conventional FDTD ensures the efficiency of simulation in CG region. While we concern the unconditionally stable method, there is not any grid omitted in our irregularly profiled fine region and any extra time wasted in solving small-scale tridiagonal matrixes cell by cell. To verify our codes, a 2-D arc component has been simulated first. Then the performance of a probe-fed normal one-eighth spherical dielectric resonator antenna (DRA), a new designed conformal-microstrip-fed one-eighth spherical shell DRA, and a four-element array with the spherical shell DRAs connected by a T-shaped power divider has been calculated by our codes. Satisfactory performance of the antenna has been obtained in return loss and radiation patterns, which are verified by measured results. The shell antenna features smaller size, lighter weight, and more convenience in conforming to the corners of the instrument housing, even with different dimensions. Most particularly, the proposed conformal subgridding scheme and its hybrid FDTD implementation perform outstandingly in simulating the thin shell antenna in terms of computer memory, CPU time, as well as accuracy.

Conformal Subgridding and Application to One-Eighth Spherical Shell Dielectric Resonator Antenna Array

A compact dual-band antenna fed by microstrip line which can be applied for the 5G communication has been proposed. By slotting symmetrical inverted L-shaped slot on the radiation patch, the antenna has realized the dual operating frequency bands which covers the 5G frequency bands commercialized in China. Particularly, the size of proposed antenna is 32 × 20 × 1.6 mm3. The fabricated antenna has been measured and its results show the operating frequency bands of the antenna range from 3.1 GHz to 3.7 GHz and from 4.67 GHz to 6.0 GHz. This proposed antenna can be applied for the 5G miniaturized devices.

A Compact Dual-band Antenna for 5G Application

A lower profile base station antenna: With dual-polarization and dual-band for sub-6 GHz application

In order to minimize the tri-band patch antenna, a slotting technique has been used, and a coplanar waveguide is fed. In the designed antenna, two U-shaped slots are grooved on the rectangular radiation patch, and the ground plane adopts angular structure. The experimental results show that the operating bands of the antenna cover 2.1-2.8 GHz, 3.3-3.9 GHz and 4.9-7.1 GHz, which is suitable for the WLAN and WiMAX systems.

Bin Gao

Papers

Conformal Subgridding and Application to One-Eighth Spherical Shell Dielectric Resonator Antenna Array

A Compact Dual-band Antenna for 5G Application

A lower profile base station antenna: With dual-polarization and dual-band for sub-6 GHz application

Design of A Miniaturization Tri-band Slot Antenna for WLAN and WiMAX Application