A novel receiver-transmitter metasurface for a high-aperture-efficiency Fabry-Perot resonator antenna

This paper presents a novel coupled receiver-transmitter metasurface(MS)which is used to realize a high-aperture-efficiency Fabry-Perot resonator antenna.The unit cell of the MS adopts a slot-coupling procedure to realize energy transmission from the receiver patch to the radiator patch.This approach makes it easier to independently control the transmission magnitude and phase.Based on this characteristic,the transmission coefficients of different unit cells on the MS can be optimized by a genetic algorithm.Then,nearly uniform electric amplitude and phase distribution across the aperture field of the antenna are achieved.Therefore,the gain and aperture efficiency of the antenna are improved.A prototype of the optimized antenna is fabricated and measured to validate the design.The measured gain of the fabricated antenna reaches 17.3 dBi with an aperture efficiency of 94.5%.A higher aperture efficiency is obtained with the proposed antenna which has a low profile and simple structure.

Dielectric Resonator Magnetoelectric Dipole Arrays with Low Cross Polarization,Backward Radiation,and Mutual Coupling for MIMO Base Station Applications

Dielectric resonator magnetoelectric dipole(DRMED)arrays with enhanced isolation,reduced cross-polarization,and backward radiation are proposed for base station(BS)applications.The proposed antenna comprises an elevated dielectric resonator antenna(DRA)on a small metal plate above a sizeable common ground plane.The DRA is designed in its T Eδ11 mode,acting like a magnetic dipole.The surface current excited by the differential probes flowing on the small ground plane is equivalent to an electric dipole.Since these two equivalent dipoles are orthogonal,they have the magnetoelectric dipole characteristics with reduced backward radiation.Meanwhile,the small ground planes can be treated as decoupling structures to provide a neutralization path to cancel the original coupling path.A linearly-polarized 4-element prototype array was verified experimentally in previous work.Here,a dual-polarized DRMED antenna is presented to construct a 2-element and 4×4 array for BS applications.To investigate its MIMO performance,sophisticated multi-cell scenario simulations are carried out.By using the proposed dualpolarized DRMED array,the cellular system capacityis improved by 118.6%compared to a conventional DRA array.This significant MIMO system improvement is mainly due to the reduced backward radiation and,therefore,reduced inter-cell interferences.Measurements align well with the simulations.

Dielectric Patch Resonator and Antenna

This paper presents an overview of dielectric patch(DP)antennas developed in recent years.The employed DP resonator composed of a DP and a bottom substrate is analyzed comprehensively here,enabling the easy realization of a quasi-planar DP antenna.It combines the dual advantages of the conventional microstrip patch(MP)antenna and dielectric resonator(DR)antenna in terms of profile,gain,bandwidth,radiation efficiency,and design freedom.Furthermore,the DP antenna inherits the multi-mode characteristic of the DR antenna,thus it has a large number of high-order modes,including TMmn mode and TEmn mode.The high-order modes are widely applied,for example,by combining with the dominant TM10 mode to expand the bandwidth,or selecting multiple higher-order modes to implement a high-gain antenna.Additionally,the non-radiation high-order modes are also utilized to produce natural radiation null in filtering antenna design.In this paper,the design theories and techniques of DP antenna are introduced and investigated,including calculation and control methods of the resonant mode frequencies,analysis of the radiation mechanism,and applications of the multi-mode characteristic.This overview could provide guidance for the subsequent antenna design,thus effectively avoid time-consuming optimization.

Triple-Band Circularly Polarized Dielectric Resonator Antenna (DRA) for Wireless Applications

This paper proposes a new dielectric resonator antenna(DRA)design that can generate circularly polarized(CP)triple-band signals.Atripleband CP DRA antenna fed by a probe feed system is achieved with metal strips structure on side of DRA structure.The design start with conventional rectangular DRA with F shaped metal strips on DRA structure alongside the feed.Then,the F metal strip is enhanced by extending the length of the metal strip to obtain wider impedance bandwidth.Further improvement on the antenna performance is observed by improvised the conventional DRA structure.The method of removing part of DRA bottom resulted to higher antenna gain with triple band CP.The primary features of the proposed DRA include wide impedance matching bandwidth(BW)and broadband circular polarization(CP).The primary features of the proposedDRAinclude wide impedance matching bandwidth(BW)and broadband circular polarization(CP).The CP BW values recorded by the proposed antenna were∼11.27%(3.3–3.65 GHz),12.18%(4.17–4.69 GHz),and 1.74%(6.44–6.55 GHz)for impedance-matching BW values of 35.4%(3.3–4.69 GHz),1.74%(5.36–5.44 GHz),and 1.85%(6.41–6.55 GHz)with peak gains of 6.8 dBic,7.6 dBic,and 8.5 dBic,respectively,in the lower,central,and upper bands.The prototype of the proposed antenna geometry was fabricated and measured.A good agreement was noted between the simulated and the measured results.

Review:Research progress on Fabry-Perot resonator antenna

The Fabry-Perot resonator (FPR) antenna has found wide applications in microwave and millimeter waves and recently attracted considerable interest. In this paper, a summary of planar and cylindrical structures, analytic models and research development is presented, and a comparison between these structures and analytic models is made, showing that such analytic models as the FP cavity mode, electromagnetic band gap (EBG) defect mode, transmission line mode, and leaky-wave mode are consistent when applied to analyze this type of resonator antenna. Some interesting topics under recent research, including dual or multi-band, improvement of gain bandwidth, low profile and beam control, are surveyed.

A Review of Wideband Circularly Polarized Dielectric Resonator Antennas

This article presents a technical review of circularly polarized(CP) dielectric resonator antennas(DRA) for wideband applications.The primary objective of this review is,to highlight the techniques used by different researchers for generating circular polarization in DRA.First,a general idea of circular polarization and it advantages over linear polarization is presented,and then all the major developments made in the CP DRA are highlighted.The emphasis of the paper is on the wideband circularly polarized dielectric resonator antenna.The current state of the art and all the realizable features of the CP DRA are addressed comprehensively.Finally,some recommendations for future CP DRAs are given and the paper ends with concluding remarks.

Broadband, High Gain, Narrow Width Rectangular Dielectric Resonator Antenna with Air Gap

The broadband, narrow width, rectangular dielectric resonator antenna(RDRA) of aluminum nitride(εr=8.6) was designed and the effect of inclusion of air gap at the bottom of the dielectric resonator antenna(DRA),above the ground plane, was investigated. Gain around 7 dBi was obtained for DRA with air gap(DRAAG) over a broad bandwidth in upper X, Ku, and K bands. Further enhancement in gain could be obtained by placing a metal wall parallel to the length of DRA. However, due to the presence of metal wall, bandwidth was reduced. These structures with the metal wall are capable of operating over a wide band extending from Ku band to lower K band with the gain of around 10 dBi. CST Microwave Studio Software was used to simulate all these structures.Performance parameters of DRA with air gap were compared with several broadband DRA structures reported in recent literature. The proposed DRAAG with the metal wall in this paper is capable of operating over a wide bandwidth along with a significant gain.

Miniaturized multi-band antenna using deformed splot ring resonator

A 48 mm x 60 mm x 1 mm miniaturized multi band antenna based on deformed split ring re sonators was presented. The antenna was consisted of a micro strip line and a deformed split square ring. Its/S11/parameters were determined through numerical simulation and experimental measure ment within three working bands of 2.6 GHz to 3. 0 GHz, 3. 9 GHz to 4. 4 GHz and 5.2 GHz to 5. 8 GHz and the results showed that the parameters within all the bands were less than 10 dB. The gain at every frequency for the antenna was above 2.2 dB and it increased monotonously with the frequency from 5. 5 GHz to 7. 0 GHz.

Wideband Polarization Reconfigurable Dielectric Resonator Antenna

A wideband polarization reconfigurable dielectric resonator antenna excited by quasilumped quadrature coupler（ QLQC） is proposed. By adjusting the value of varactor diode on the QLQC feed network,both the wideband LP and CP dielectric resonator antennas（ DRA） modes can be achieved. By selecting a different feed port,left-and right-handed CP conversion can be realized.It is found that the 10 dB impedance bandwidth of the LP and CP modes are 10. 1% and 44. 9%,respectively.For the CP mode,a very wide 3 dB axial ratio bandwidth of 37. 7% can be obtained which is much larger than that of the microstrip patch counterpart（ 3. 8%）. It is worth mentioning that the wideband CP DRA has a stable broadside radiation pattern across the whole operating band where the boresight gain is larger than 3 dBi.

Design of a low-sidelobe-level and wideband dielectric resonator antenna array for 60 GHz millimeter wave communication

A low-sidelobe-level( SLL) and wideband linear dielectric resonator antenna( DRA) array is proposed for 60 GHz millimeter wave communication. The array consists of 10 wideband DRAs which work at 60 GHz and it is fed by a Chebyshev feeding network to get a low SLL. To avoid the influence from the feeding network,a U-shaped substrate and a conformal ground are used,which can separate the DRA array and the feeding network. The parameter analysis and simulated results are presented.

Gain Enhancement of Dielectric Resonator Antenna Using Electromagnetic Bandgap Structure

High gain antennas are highly desirable for long-range wireless communication systems.In this paper,a compact,low profile,and high gain dielectric resonator antenna is proposed,fabricated,experimentally tested,and verified.The proposed antenna system has a cylindrical dielectric resonator antenna with a height of 9 mm and a radius of 6.35 mm as a radiating element.The proposed dielectric resonator antenna is sourced with a slot while the slot is excited with a rectangular microstrip transmission line.The microstrip transmission line is designed for a 50impedance to provide maximum power to the slot.As a result,the proposed antenna operates at 5.15 GHz with a 10-dB absolute bandwidth of 430 MHz(4.98–5.41 GHz).It is important to mention that the gain of the dielectric resonator antenna is enhanced by the introduction of an electromagnetic bandgap(EBG)structure.In fact,EBG units are placed below the antenna,which enhances the realized peak gain from 5.32 dBi to 8.36 dBi at 5.15 GHz.More specifically,a gain enhancement of 3.04 dB is observed with the introduction of the EBG array.This antenna has several good features such as high gain,compact size,large bandwidth,and lower losses which make it a suitable choice for long-range wireless communication systems.

Novel circularly-polarized ceramic dielectric resonator antenna excited by a corner-cut square patch

A ceramic dielectric resonator antenna excited by a corner-cut square patch for the circularly-polarized operation is introduced. The effect of patch size and cut size is investigated, showing that the resonant frequency of the antenna can be changed by simply changing the patch size. The reflection, axial ratio, and radiation characteristics of the antenna are found. Measurements were carried out to verify the design. The antenna is compact in structure, which is attractive in the application as the satellite communication terminals.

A Novel Kind of Wideband Low-Profile Dielectric Resonator Antenna Suitable for Beam-scanning Applications

In this paper, a low-profile wideband dielectric resonator antenna(DRA) with a very compact planar size is investigated. The antenna consists of a high permittivity dielectric sheet on the top, a low permittivity substrate in the middle, and a probe feeding structure at the bottom. By digging an annular slot in the designated area of the square dielectric sheet, the resonant frequency of fundamental TE111 mode can be effectively increased to be close to the high-order TE131 mode. The two modes can be finally merged together, yielding a wide impedance bandwidth of16.6%. Most importantly, the combination of the two modes is done on the premise of a fixed antenna planar size, which can be very compact and suitable for beam-scanning applications. A probe feeding structure is used to excite the DRA, making the antenna simple and practical to be integrated with other RF circuits. For verification, antenna prototypes with singlefeed linear polarization and differential-feed dual polarization were fabricated and measured. Reasonable agreement between the measured and simulated results is observed.

Compact Interlaced Dual Circularly Polarized Sequentially Rotated Dielectric-Resonator Antenna Array

In this study,a compact 2×2 interlaced sequentially rotated dual-polarized dielectric-resonator antenna array is proposed for 5.8 GHz applications.The array is composed of a novel unit elements that are made of rectangular dielectric resonator(RDR)coupled to an eye slot for generating the orthogonal modes,TEδx 21 and TE1yδ1 to acquire circular polarization(CP)radiation.For the purpose of miniaturization and achieving dual polarized resonance,the array is fed by two interlaced ports and each port excites two radiating elements.The first port feeds horizontal elements to obtain left hand circular polarization(LHCP).The second port feeds vertical elements to obtain right hand circular polarization(RHCP).A quarter-wave length transformer is employed to reduce the attenuation and consequently increase the array gain performance.The 35×35 mm2(0.676λ0×0.676λ0)gains were 8.4 and 8.2 dBi for port 1 and port 2,respectively,with port isolations of−33.51 dB.The design achieves a voltage standing-wave ratio(VSWR)<−10 dB and an axial ratio(AR)<−3 dB bandwidth of 2.48%(5.766 to 5.911 GHz)for LHCP at port 1 and a VSWR<−10 dB and AR<−3 dB bandwidth of 2.28%(5.788 to 5.922 GHz)for RHCP at port 2.The findings of the proposed design validate its use for ISM band applications.

Enhancement of Characteristics of Antenna Arrays Employing S-Shaped Resonators

This paper illustrates a simple kind of tri-band printed G-shaped monopole antenna for Multiple-Input-Multiple-Output (MIMO) systems. The proposed antenna is used to achieve three operating frequencies, 2.45 GHz, 5.2 GHz and 8.2 GHz for wireless communications. To improve the isolation between the two radiating elements, we use left-handed materials composed of only S-shaped resonators to get negative refractive index at the three operating frequencies. When one layer of S-shaped resonators is employed, the antenna correlation, the diversity gain and the bandwidth are also enhanced. The simulated results are presented and evaluated with and without left-handed materials.

Wideband Sierpinski Carpet Fractal Shaped Cylindrical Dielectric Resonator Antenna for X-Band Application

In this paper, a wideband Sierpinski carpet patterned cylindrical Dielectric Resonator Antenna (DRA) operating in the X-Band is proposed. This DRA is realized from low cost Teflon. An impedance bandwidth of 50% is obtained cove- ring the entire X-band with similar radiation pattern throughout the band. The average peak gain within the band is about 5.5 dBi.

Design of Rectangular Dielectric Resonator Antenna Fed by Dielectric Image Line with a Finite Ground Plane

A Rectangular Dielectric Resonator Antenna (RDRA) fed by Dielectric Image Line (DIL) through a narrow slot placed on a finite ground plane is numerically investigated. The effects of ground plane size on the radiation performance of the antenna are carried out. To increase the antenna gain, four sidewalls are placed around the corners of the ground. Also, a reflector is placed at the back side of the structures to reduce backward radiation. Results show that 7.7 dB gain is obtained at 10 GHz with a broadside radiation pattern. For the DRA with four sidewalls maximum gain of 10.4 dB at 10.4 GHz is achieved which is 2.7 dB higher than the gain of the structure without them. The effect of air gap between dielectric resonator and ground plane is also investigated. The results show that with increasing the distance between the DR and ground, antenna gain is decreased.

Ultra-Wideband Annular Ring Fed Rectangular Dielectric Resonator Antenna for Millimeter Wave 5G Applications

In this article an ultra-wideband rectangular Dielectric Resonator Antenna is designed for millimeter wave 5G frequency band applications.Indoor 5G communications require antenna system with wide bandwidth and high efficiency to enhance the throughput in the channel.To fulfill such requirements a Dielectric Resonator Antenna(DRA)is designed here which has achieved an ultra-wide bandwidth of 20.15%(22.32–27.56 GHz)which is 5.24 GHz of bandwidth centered at 26 GHz as resonating frequency.This covers the complete band 30(24.3–27.5 GHz)of 5G spectrum.26 and 28 GHz are considered as most popular frequencies in millimeter wave 5G communications.The aperture fed DRA designed here has also achieved an efficiency of 96 percentage with maximum radiation in the broadside direction(Phi=0,Theta=0).The measured gain of the DRA is 6.3 dB.The DRA designed here has dimensions of 0.25λ0×0.22λ0×0.12λ0.under the characteristic’s mode.The DRA is placed over a substrate with dimensions 0.5λ0×0.5λ0×0.02λ0.A cross slot aperture has been made on the ground plane which is placed above to the substrate.Here a full ground plane is used to resonate the antenna and is of similar dimension to the substrate.A microstrip line with two concentric rings makes an annular feed structure is used to excite the DRA and is placed below the substrate.The DRA is excited here in characteristics mode TE1Y1 and is the only mode of excitation.The DRA is linearly polarized,and the characteristic mode of excitation is maintained with 50 Ohm input impedance of the antenna.The DRA also gives here a good difference between the co-pol and cross pol approximately 15 to 20 dB.This antenna is more suitable for 5G indoor applications in millimeter wave frequency band centered at 26 GHz.

UltrahighQ Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)microwave dielectric ceramics for temperature-stable millimeter-wave dielectric resonator antennas

Microwave dielectric ceramics should be improved to advance mobile communication technologies further.In this study,we prepared Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics with nonstoichiometric Sr^(2+)ratios based on our previously reported SrY_(2)O_(4) microwave dielectric ceramic,which has a low dielectric constant and an ultrahigh quality factor(Q value).The ceramic exhibited a 33.6% higher Q-by-frequency(Q×f)value(Q≈12,500)at x=0.02 than SrY_(2)O_(4).All Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics exhibited pure phase structures,although variations in crystal-plane spacings were observed.The ceramics are mainly composed of Sr-O,Y1-O,and Y_(2)-O octahedra,with the temperature coefficient of the resonant frequency(τ_(f))of the ceramic increasing with Y_(2)-O octahedral distortion.The ceramic comprises uniform grains with a homogeneous elemental distribution,clear grain boundaries,and no obvious cavities at x=0.02.The Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics exhibited good microwave dielectric properties,with optimal performance observed at x=0.02(dielectric constant(εr)=15.41,Q×f=112,375 GHz,and τ_(f)=-17.44 ppm/℃).The τ_(f) value was reduced to meet the temperaturestability requirements of 5G/6G communication systems by adding CaTiO_(3),with Sr_(1.02)Y_(2)O_(4.02)+2wt% CaTiO_(3) exhibiting ε_(r)=16.14,Q×f=51,004 GHz,andτf=0 ppm/℃.A dielectric resonator antenna prepared using Sr_(1.02)Y_(2)O_(4.02)+2wt%CaTiO_(3) exhibited a central frequency of 26.6 GHz,with a corresponding gain and efficiency of 3.66 dBi and 83.14%,respectively.Consequently,Sr_(1.02)Y_(2)O_(4).02-based dielectric resonator antennas are suitable for use in 5G millimeter-wave band(24.5-27.5 GHz)applications.