On the Differentially Fed Rectangular Dielectric Resonator Antenna

A differentially fed rectangular dielectric resonator antenna (DRA) is studied using the finite-difference time-domain (FDTD) method. The fundamental TE₁₁₁ mode of the rectangular DRA is excited at 2.4 GHz, with a 10-dB differential impedance bandwidth (|S_dd11| < -10 dB) of ~10.4%. To verify the theory, measurements were carried out, and reasonable agreement between theory and experiment is obtained. The effects of the magnitude and phase imbalances on the DRA impedance and radiation pattern are investigated.     

Circularly polarized circular sector dielectric resonator antenna

A circular sector dielectric resonator antenna (DRA) with circular polarization and a single feed is investigated and demonstrated. The design utilizes the radius to height ratio and feed position of the circular sector DRA to excite two resonant modes that are spatially orthogonal in polarization and in phase quadrature. Experimental results are provided for the design and these demonstrate that the circular sector DRA produces circular polarized radiation with axial ratio less than 3 dB over a 10% bandwidth     

Circularly polarised dielectric resonator antenna with metallicstrip

A new design of circularly polarised slot fed dielectric resonator antenna (DRA) is presented. The dissymmetry of the design enabling circular polarisation relies on a metallic strip printed on top of the resonator. Simulations are compared with measurements for a single antenna as well as a four DRA sequential rotation array     

Circular Polarization Dielectric Resonator Antenna Excited by Single Loop Feed

A new feeding method for the circular polarization (CP) dielectric resonator antenna (DRA) is proposed in this letter. Two orthogonal modes (TE^x_δ11, TE^y_1δ1,) of the rectangular DRA are excited by a 90° phase difference of the differential and common modes currents of the proposed feeding structure. To demonstrate the good CP performance of the proposed method, a right‐hand CP DRA for a global positioning system was designed. The impedance bandwidth of the proposed antenna for S₁₁相似文献   

Study on Sequential Feeding Networks for Subarrays of Circularly Polarized Elliptical Dielectric Resonator Antenna

Circularly polarized (CP) dielectric resonator antenna (DRA) subarrays have been numerically studied and experimentally verified. Elliptical CP DRA is used as the antenna element, which is excited by either a narrow slot or a probe. The elements are arranged in a 2 by 2 subarray configuration and are excited sequentially. In order to optimize the CP bandwidth, wideband feeding networks have been designed. Three different types of feeding network are studied; they are parallel feeding network, series feeding network and hybrid ring feeding network. For the CP DRA subarray with hybrid ring feeding network, the impedance matching bandwidth (S₁₁<-10 dB) and 3-dB AR bandwidth achieved are 44% and 26% respectively     

基于介质片加载实现MIMO介质谐振器天线解耦

提出了一种通过在介质谐振器(DR)上表面侧边加载介质片(DS)来实现1×2 MIMO介质谐振器天线(DRA)解耦的新方法。1×2 MIMO DRA采用双层介质基板结构以优化阻抗匹配特性和辐射特性,两DR的边到边间距为0,天线工作在毫米波频段。所加载的DS使得DR内的场重新分布并向DS加载区域以及DS内集中,从而减弱耦合到另一DR单元的场强以实现解耦效果。基于ANSYS HFSS的仿真结果表明天线的-10 dB阻抗匹配带宽为25.6%(22.75～29.43 GHz),带内最大实现了30 dB的隔离度的增强。     

Comparative study on the mutual coupling between different sized cylindrical dielectric resonators antennas and circular microstrip patch antennas

A systematic comparative study on the mutual coupling (S/sub 21/) between dielectric resonator antennas (DRAs) and microstrip patch antennas is presented. The mutual coupling between two cylindrical probe-fed DRAs is studied for different radius to height (a/L) ratios. It is found that the mutual coupling decreases with the radius to height ratio. Comparison between mutual coupling of probe-fed cylindrical DRAs and circular microstrip patch antennas with different dielectric substrates are also studied. The mutual coupling between DRAs is 2 dB stronger than between microstrip patch antennas when the patch is etched on a dielectric substrate of a dielectric constant close to the permittivity of the DRA. The mutual coupling of the circular patch antennas reduces with the dielectric constant of the substrate.     

Bandwidth Enhancement of Circularly Polarized Dielectric Resonator Antenna

Axial‐ratio (AR) bandwidth enhancement is achieved for a circularly polarized (CP) cylindrical dielectric resonator antenna (DRA) using a wideband hybrid coupler (WHC) combined with dual probe feed. The presented WHC, comprised of a Wilkinson power divider and a wideband 90° shifter, delivers good characteristics in terms of 3 dB power splitting and consistent 90° (±5°) phase shifting over a wide bandwidth. In turn, the proposed CP DRA, for the employment of the WHC, in place of conventional designs, provides a significant enhancement on AR bandwidth and impedance matching. The antenna prototype with the WHC exhibits a 3 dB AR bandwidth of 48.66%, an impedance bandwidth of 52.5% for voltage standing wave ratio (VSWR) ≤ 2, and a bandwidth of 44.66% for a gain of no less than 3 dBi. Experiments demonstrate that the proposed WHC is suitable for broadband CP DRA design.     

Strip-fed rectangular dielectric resonator antennas with/without a parasitic patch

A rectangular dielectric resonator antenna (DRA) was studied theoretically and experimentally. The rectangular DRA is excited by a strip, which is compatible with a coaxial probe. Both linearly polarized (LP) and circularly polarized (CP) fields of the antenna are considered. In previous studies of the LP rectangular DRA, only the fundamental TE/sub 111/ mode has received much attention. In this paper, it is found that the fundamental TE/sub 111/ mode, together with the higher-order TE/sub 113/ mode, can be used to design a wide-band LP DRA. The bandwidth of the dual-mode DRA can be over 40% for a conventional rectangular DRA with a simple feed. For the CP mode, a parasitic patch is attached on a side wall of the DRA to excite a degenerate mode. In both the LP and CP cases, the finite-difference time-domain (FDTD) method is used to analyze the problems. The results agree reasonably with measurements.     

Conformal strip excitation of dielectric resonator antenna

A new excitation scheme that employs a conducting conformal strip is proposed for dielectric resonator antenna (DRA) excitation. The new excitation scheme is successfully demonstrated by using a hemispherical DRA whose exact Green function is found using the mode-matching method. The moment method is used to solve the unknown strip current from which the input impedance is obtained. Novel recurrence formulas were obtained so that the impedance integrals are evaluated analytically. This solves the singularity problem of the Green function and substantially reduces the computation time. An experiment was carried out to verify the theory. The co- and cross-polarized field patterns are also shown. In addition, an experimental technique which deals with the problem of an air gap between the DRA and the ground plane is presented     

Broadband dielectric resonator antennas excited by L-shaped probe

Dielectric resonator antennas (DRAs) designed for broadband applications and excited by L-shaped probe are presented. The L-probe is housed under an air-filled groove between the DRA and the ground plane. A 32% matching bandwidth (S/sub 11/<-10 dB) is achieved with broadside radiation patterns. The new structure is constructed from the same dielectric materials. Thus, it is mechanically better than other wideband DRAs that consist of more than one dielectric material such as the stacked DRA. Some results are verified experimentally. The performance of this DRA and those fed by traditional probes and slots are investigated numerically. In addition, comparisons between L-probe excited DRAs and L-probe excited microstrip patch antennas are discussed.     

Dual band dielectric resonator antenna for wireless application

The proposed technique is an integration of a slot antenna and a dielectric resonator antenna (DRA). This is designed without compromising miniaturisation and efficiency. It is observed that the integration of slot and dielectric structure itself may be merged to achieve extremely wide bandwidth over which the antenna polarisation and radiation pattern are preserved. Here the effect of slot size on the radiation performance of the DRA is studied. The antenna structure is simulated using the CST software. The simulated results are presented and compared with the measured result. This DRA has a gain of 7.1 and 6.3?dBi at 5.7 and 8.1?GHz, respectively, its 10?dB return impedance bandwidth of nearly 4.5% and 5.5% at two resonating frequencies. A total of 98% efficiency has been achieved from the configuration. It is shown that the size of the slot can significantly affect the radiation properties of the DRA and there are good agreements between simulation and measured results.     

Experimental investigation for wideband perforated dielectric resonator antenna

A wideband perforated dielectric resonator antenna (PDRA) is presented. The effective permittivity of the dielectric resonator is altered by drilling holes into a circular ring lattice inside the DRA. The PDRA is equivalent of having an annular ring with lower permittivity outside the cylindrical disk, resulting in enhanced impedance bandwidth. The measured bandwidth of a prototype PDRA with relative permittivity 10.2 is 26.7% (S/sub 11/<-10 dB).     

A novel type of waveguide polarizer with large cross-polarbandwidth

A wideband quarter-wave polarizer is presented having a rectangular cross-section, where all four walls are loaded with a dielectric or artificial dielectric. A much larger bandwidth compared to existing polarizers can be obtained without increasing the insertion loss. A polarizer so constructed was fabricated and measured. The polarizer had a differential phase shift within 90°±0.7° corresponding to 44 dB isolation, insertion loss below 0.06 dB, and return loss below -24 dB (VSWR <1.13) over the frequency band 10.95 to 14.50 GHz     

Wideband simple cylindrical dielectric resonator antennas

Bandwidths of the coaxial fed and aperture coupled cylindrical dielectric resonator antennas (DRAs) with broadside radiation patterns are enhanced by exciting the HEM/sub 11/spl Delta// (1相似文献   

Two-Layer Dielectric Rod Antenna

A dielectric rod antenna (DRA) design that consists of two concentric dielectric cylinders and achieves more than 4:1 bandwidth is described. The new DRA is composed of a launcher section, followed by a waveguide section and ends in a radiation section. The utilization of two-layer structure avoids the excitation of high-order modes, thus extending the operational bandwidth. Properly chosen radii and dielectric constants of each layer in conjunction with a properly tapered radiation tip ensure frequency-insensitive radiation properties (gain and pattern) and stable phase center. The design example of a two-layer dual-polarization DRA presented in this paper operates from 2 to 8 GHz and produces symmetric radiation patterns with half-power beamwidth greater than 55deg. The current design is one of the most ideal antennas to be used as a near-field probe or reflector feed.     

Excitation of dielectric resonator antenna using a soldered-throughprobe

A soldered-through probe is used to excite the dielectric resonator antenna (DRA). A cylindrical ring DRA is used to demonstrate the feasibility of this excitation method. The return loss, radiation pattern, and antenna gain of the new configuration are studied     

基于可开关桥式耦合结构的介质滤波开关

作为无线通信时分双工子系统的重要元件之一,目前绝大多数已报道的滤波开关是利用微带线结构实现的,然而其较高的损耗已逐渐不能满足通信系统的要求.文中针对介质滤波器提出了一种可开关桥式耦合结构,该耦合结构由印刷电路板上的一部分金属带条和伸入介质腔体内部的两根金属探针构成.将PIN管并联在金属带条上,通过控制PIN管的偏置电压...     

Bandwidth improvement for a microstrip-fed series array ofdielectric resonator antennas

The impedance and pattern bandwidth of an array of dielectric resonator antennas series fed by a microstrip line was significantly improved by replacing individual DRAs with paired DRAs. The DRAs in each pair are spaced slightly <λ_g/4 apart so that their input reflections cancel. An array of eight DRA pairs was designed and fabricated, and its performance was compared to an array of eight single elements. The 10 dB return loss bandwidth improved from 2 to 18% and the 3 dB gain pattern bandwidth improved from 12 to 17%     

Ultra-wideband (from DC to 110 GHz) CPW to CPS transition

A new ultra-wideband, low-loss and small-size coplanar waveguide (CPW) to coplanar strip (CPS) transition which can be used from DC to 110 GHz is presented. The proposed transition connects CPW with CPS by the reformed air-bridge. Two ground planes of CPW are tied at their ends by a line and the centre of the line is connected to the ground strip of CPS by another line. Owing to the symmetry of the proposed structure, the currents of two ground planes of CPW are combined with the same phase and transferred to the ground strip of CPS. With height of 3 μm, the signal line of CPW passes over two connecting lines and is connected to the signal strip of CPS. For the back-to-back transition structure, insertion loss <1 dB and return loss >15 dB are obtained from 0.5 to 110 GHz