Rectangular Dielectric Resonator Antenna Array Research Articles

A Low-Profile Dielectric Resonator Antenna Array for OAM Waves Generation at 5G NR Bands.

This paper presents the generation of orbital angular momentum (OAM) vortex waves with mode +1 using dielectric resonator antenna (DRA) array. The proposed antenna was designed and fabricated using FR-4 substrate to generate OAM mode +1 at 3.56 GHz (5G new radio band). The proposed antenna consists of 2 × 2 rectangular DRA array, a feeding network, and four cross slots etched on the ground plane. The proposed antenna succeeded in generating OAM waves; this was confirmed by the measured radiation pattern (2D polar form), simulated phase distribution, and intensity distribution. Moreover, mode purity analysis was carried out to verify the generation of OAM mode +1, and the purity obtained was 53.87%. The antenna operates from 3.2 to 3.66 GHz with a maximum gain of 7.3 dBi. Compared with previous designs, this proposed antenna is low-profile and easy to fabricate. In addition, the proposed antenna has a compact structure, wide bandwidth, high gain, and low losses, thus meeting the requirements of 5G NR applications.

Effects of Mutual Coupling on Gain and Beam Width of a Linear Array of a Dielectric Resonator Antenna for Main Beam Scanning Applications.

The effects of mutual coupling on the scanning characteristics of a four-element linear rectangular dielectric resonator antenna array (RDRA) are investigated for different inter-element spacing in this work. In particular, the gain and half-power beam width (HPBW) of an RDRA are studied for various scan angles in the E- and H-plane configurations. It is shown that for both the E and H planes, mutual coupling has an adverse effect on the performance of both phased array configurations. The H-plane array, however, is more stable than the E-plane array in terms of a gain and beam width performance comparison. The HPBW increases and gain decreases more in the E plane than the H plane when the scan angle is increased.

Aperture coupled modified rectangular dielectric resonator antenna arrays for X-band applications

This paper proposes an aperture coupled 3×3 rectilinear geometry-based periodic modified rectangular dielectric resonator antenna array for X-band applications. In this paper, the complex electromagnetic field problem of RDRA is addressed through a modified rectilinear-shaped DRA. Notches are created on the dielectric resonator to alter the normal components of the electric field pattern instantaneously. It leads to the reduction in the magnitude of reactive current density, resulting in a lessening of the Q-factor and enhancement of the bandwidth. This antenna shows multiband response, resonating at 8.42, 10.08, and 11.60 GHz frequency with a peak gain of 12.94 dBi at 9.75 GHz with consistent gain stability over the entire frequency band of operation. The radiation efficiency is around 96.1% due to low losses. The impedance bandwidths for different bands are 4.51%, 2.77%, and 4.56% at the resonating frequency of 8.42, 10.08, and 11.60 GHz. A comparative analysis of input and output characteristics is carried out between single, double, and nine-cell arrays. The designed antenna is excited by a branch line series-corporate constrained micro-strip feeding network with three apertures. This novel design is suitable for microwave X-band applications.

Wideband and High Efficiency 64-Element RDRA Array for Radar Applications

This paper presents the capabilities of an $8\mathrm {\times }8$ Rectangular Dielectric Resonator Antenna (RDRA) planar array with broad bandwidth and high gain. To improve shielding of a multi-stage feeding network, the proposed array is designed using a stripline feeding network with two different substrates. To enhance impedance matching while keeping a sufficient F/B ratio of 20 dB, the lower ground of the stripline has a smaller dimension than the upper ground plane. The proposed array covers the frequency band from 3.79 to 6.29 GHz with 50% fractional bandwidth. The peak realized gain ranges from 18 to 22 dBi, with 85% of radiation efficiency throughout the frequency of interest. The overall size and weight of the array is $215\mathrm {\times } 215 \mathrm {\times }14.5$ mm3 and 650 g, respectively. Furthermore, the radiation patterns appear as low as 15 dB of peak-to-side lobe level with 25 dB cross polarization level, which makes the proposed array suitable for UAS (Unmanned Aerial System) radar applications. The measurements and simulations agree considerably.

Millimeter-Wave Rectangular Dielectric Resonator Antenna Array With Enlarged DRA Dimensions, Wideband Capability, and High-Gain Performance

In this communication, a rectangular dielectric resonator antenna (DRA) is integrated with a backed cavity to enlarge the DRA side length by 1.8 times. The backed cavity also reduces the sensitivity of the DRA resonance to the DRA size, resulting in a relaxed fabrication tolerance. Based on the enlarged DRA design, a stacked DRA (sDRA) is proposed to improve the bandwidth from 8.7% to 15% and enhance the realized gain by an average of 1.5 dB. The proposed mechanisms are verified by fabricating a $4\times4$ sDRA array with an enlarged DRA side length of 1.8 mm ( $0.40 {\lambda }$ ), an improved bandwidth of 62.7–73.9 GHz (16.4%), and an enhanced measured gain of up to 17.2 dBi. The enlarged DRA dimension permits a higher DRA operating frequency without reducing the DRA size. The proposed millimeter-wave (mmW) sDRA array provides a wide bandwidth and high-gain solution for 67 GHz unlicensed band communications.

Design and Development of Dielectric Resonator Antenna Using Ceramic Materials: An Overview

The basics of design of microstrip aperture-coupled ceramic rectangular dielectric resonator antenna (RDRA) are given. Methods of estimation of antenna dimensions, impedance matching, excitation procedure and choice of suitable materials to be used in the fabrication are briefly described. The RDRA dimensions are obtained by solving the transcendental equation derived from Maxwell equations using dielectric waveguide model. Some ceramics are found useful for fabrication of DRAs that yield large bandwidth and gain are summarized. An attempt to explore the application of dielectric materials having small dielectric loss (tan δ > 0.01) has been made by developing RDRA configurations using one, two and three element arrays, and effect of dielectric loss on their performance is studied using ANSYS HFSS simulations. For a RDRA array comprising of three elements, where the middle parasitic element has small dielectric loss (tan δ ~ 0.1) and the outer elements are aperture coupled, the gain decreases only by 2.7%, while the bandwidth is enhanced by 3%. The findings indicate the possibility of using ceramics having small dielectric loss such as Ba1−xSrxTiO3 (x = 0.35, tan δ ~ 0.1) with some trade-off with gain by using suitable designs. Equivalent circuit modelling useful in understanding the performance of microstrip aperture-coupled RDRA is also presented.

Design and Optimization of SIW Center-Fed Series Rectangular Dielectric Resonator Antenna Array With 45° Linear Polarization

The modeling, design, and optimization of a new substrate integrated waveguide middle-fed series rectangular dielectric resonator antenna array with 45° linear polarization are presented. The implicit space mapping technique is applied for the optimization of the antenna array. A tunable circuit model is built, which serves as the coarse/surrogate mode, and a full-wave solver is used as the fine model. High design and optimization efficiency is demonstrated using an eight-element array. The reflection coefficient of the array antenna is optimized with only two iterations. The experimental data for the eight elements antenna array, operating at the millimeter-wave band (34–36 GHz), are used for the validation of both performance of the design and modeling techniques. The measured radiation pattern demonstrates a broadside beam with a maximum radiated gain of 13.55 dB over an operating impedance bandwidth of 2.2 GHz.

Low‐profile quad‐band perforated rectangular dielectric resonator antenna for wireless communications

A novel low-profile, high-efficiency quad-band perforated rectangular dielectric resonator antenna (RDRA) for wireless communication applications has been introduced. The quad-band perforated RDRA consists of a single dielectric sheet virtually divided into four sections. The perforation technique is used to alter the dielectric constant of each section. The effective dielectric constant is changed according to the perforation radii and their separation distances. The quad-band RDRA is made of four blocks of different materials. An investigation of the radiation characteristics of the quad-band perforated RDRA has been introduced. Two quad-band perforated RDRA array elements are introduced for multiple-input–multiple-output applications. The effect of separation distances between the array elements for two different array arrangements has been studied. Cutting slots in the ground plane is employed to minimise the mutual coupling between the perforated RDRA array elements. The antenna structure is designed and analysed using the finite-integration technique, and confirmed using the finite-element technique.

Theoretical and Experimental Investigations on Rectangular Dielectric Resonator Antenna Array for Radar and Satellite Application

ABSTRACTIn this article, the theoretical, simulation, and experimental study of high gain dual segment 4-element linear broadside rectangular dielectric resonator antenna array shaping the -field components with copper sheet on one side, has been carried out. Copper strip connected to microstripline is introduced to excite the proposed dielectric resonator antenna array to achieve the coupling for dielectric resonator material with lower dielectric constant (≤10). Proposed antenna array with copper strip excitation has been successfully fabricated and tested. The voltage standing wave ratio, gain, and radiation characteristics of the proposed array have been explored using Ansoft HFSS 15.0 simulation software. Antenna array is also investigated using the finite-difference time-domain numerical technique. Good agreement between the simulated, calculated, and measured results is obtained. High gain and appreciable bandwidth together with low cross polarization is always defiance for researchers. The gain of the proposed array has been raised by a factor of 6.05, compared with the gain of a single dielectric resonator antenna. The proposed antenna provides a high gain of 10.50 dBi with a medium bandwidth of 512 MHz (3.44–3.95 GHz) and low cross-polarization, which is definitely better than previous reported literatures. The proposed structure is a good substitute to patch antennas in array applications as it offers high gain, medium bandwidth, and nice impedance matching. However, one disadvantage compared to microstrip arrays is the added fabrication complexity involved in having to place and bond the individual elements. In the future, for mass production applications, this process could be automated using robotic pick-and-place machines.

Direct microstrip line-fed dielectric resonator antenna array

In this paper, a 1×4 rectangular dielectric resonator antenna array is designed using direct microstrip lines at the center frequency of 6.7 GHz for obtaining higher directive gain. A prototype has been fabricated with Arlon AD270 substrate and experimental measurements have been carried out. The array offers an impedance bandwidth of 9.6% and a maximum gain of 11.8 dBi at the operating frequency. A close agreement between simulated and measured results has been obtained.

Design, Fabrication, and Measurement of Dual-Segment Rectangular Dielectric Resonator Antenna Array Excited with Conformal Strip for S-Band Application

ABSTRACTA conformal strip connected to a microstrip line is proposed to excite the professed dielectric resonator antenna array to achieve the critical coupling for material having lower dielectric constants of less than 10. Fabrication of two-element dual-segment linear broadside rectangular dielectric resonator antenna array with copper plates on one side has been successfully presented for the first time. The combination of high gain and wide bandwidth with low cross-polarization is always a challenge for researchers. The gain of a two-element array has been increased by a factor of 2.0 compared with the gain of a single dielectric resonator antenna, and there is also a 6.14% increase in bandwidth of the proposed array compared to the single element rather than a decrement in bandwidth as reported in previous studies. Although the gain and bandwidth are not very high for the two-element case, the proposed fabrication technique can be applied for a large number of elements for higher gain application, and the structure can be modified for other desired bands of operation. The proposed array can be used as a medium-gain wideband antenna or can form a sub-array in a large low-profile structure for high-gain applications.

HIGH GAIN CIRCULARLY POLARIZED RECTANGULAR DIELECTRIC RESONATOR ANTENNA ARRAY WITH HELICAL-LIKE EXCITER

A novel (2£2) high gain circularly polarized rectangular dielectric resonator antenna array integrated with helical-like exciter is proposed. The array ofiers a maximum gain of 12.9dBi at the operating frequency. The circular polarization is obtained by incorporating helical-like exciter in the array structure. A prototype of the proposed conflguration integrated with helical-like exciter has been fabricated and tested, and the idea has been verifled. A good agreement has been obtained between the measured and simulated results.

A Linear Rectangular Dielectric Resonator Antenna Array Fed by Dielectric Image Guide With Low Cross Polarization

Design of a linear array of rectangular dielectric resonator antennas (DRAs) fed by dielectric image guide (DIG) is presented. Coupling between the DIG and the DRAs is predicted using the effective dielectric constant method. In order to achieve a specific power distribution, the power coupled to each DRA is controlled by changing the spacing between the DRAs and the DIG. Cross polarization reduction is achieved by wrapping a conducting strip around the middle of the DRA without affecting the co-polarized radiation pattern. The antenna is fabricated and tested. Good agreement between the measured and computed results is obtained.

Aperture Coupled Rectangular Dielectric Resonator Antenna Array Fed by Dielectric Image Guide

This paper presents the design of a rectangular dielectric resonator antenna array coupled to narrow slot apertures that are fed by dielectric image guide (DIG). The DIG is excited by an X-band rectangular waveguide through a waveguide transition, and DIG tapering is used to match between the waveguide and the DIG. Reflection cancelling slots are added near the original slots to improve impedance matching. Since the slots radiate in both directions, a reflecting conducting plate is inserted above the DIG to decrease the back radiation of the antenna. The antenna is fabricated and the measured results are compared to the simulated results.