Showing papers in "IEEE Antennas and Wireless Propagation Letters in 2015"

Frequency Diverse Array Radar With Logarithmically Increasing Frequency Offset

Abstract: In recent years, frequency diverse array (FDA) radar with uniform interelement frequency offset has been proposed and investigated. It has been shown that the beampattern of this form of radar is range-angle-dependent, and it exhibits maxima at multiple range values. Due to the multiple maxima, a number of reflectors located at any of the maxima can interfere the target-return, thus deteriorating signal-to-interference-plus-noise ratio (SINR). In this letter, we have proposed FDA with logarithmically increasing frequency offset to achieve a beampattern with a single maximum at the target location. A transmitter for the proposed radar system has been described and analyzed mathematically. Furthermore, the transmit beampattern has been derived and plotted and compared to that of phased-array radar (PAR) and the existing forms of FDA employing uniform frequency offset.

Orbital-Angular-Momentum-Based Electromagnetic Vortex Imaging

Abstract: A novel radar imaging technique based on orbital angular momentum (OAM) modulation is presented. First, the generation of electromagnetic (EM) vortex wave, which carries the OAM, using incrementally phased uniform circular array (UCA) is introduced, and factors that affect the phase-front distribution are analyzed. Subsequently, echo signal models of both multiple-in–multiple-out and multiple-in–single-out modes are established. The target images are obtained using the fast Fourier transform (FFT) and back-projection methods. Simulation results demonstrate that orbital angular momentum has the prospect for acquiring the azimuth information of radar target. The signal of both OAM modulation and frequency modulation can be used to obtain two-dimensional radar target image. The work can benefit the development of novel information-rich radar based on orbital angular momentum, as well as radar target recognition.

Isolation Enhancement of a Very Compact UWB-MIMO Slot Antenna With Two Defected Ground Structures

Abstract: A very compact ultrawideband (UWB) multiple-input multiple-output (MIMO) antenna with high isolation is presented in this letter. The proposed antenna, consisting of two UWB slot antennas, has a very compact size of $22 \times 26~\hbox{mm}^{2}$ , which is smaller than most of UWB antennas only with single antenna element. A T-shaped slot is etched on the ground to improve the impedance matching characteristic in the low-frequency and reduce the mutual coupling for the frequencies $ \geq 4~\hbox{GHz}$ . By etching a line slot to cancel out original coupling, isolation enhancement at the 3–4 GHz band is achieved. The antenna possesses a low mutual coupling of less than $ - 18~\hbox{dB}$ over the operating band from 3.1–10.6 GHz. The performance of this antenna both by simulation and by experiment indicates that the proposed antenna is a good candidate for UWB applications.

A Compact Koch Fractal UWB MIMO Antenna With WLAN Band-Rejection

Abstract: In this letter, a compact octagonal shaped fractal ultrawideband multiple-input–multiple-output antenna is presented, and its characteristics are investigated In order to achieve the desired miniaturization and wideband phenomena, self-similar and space filling properties of Koch fractal geometry are used in the antenna design These fractal monopoles are placed orthogonal to each other for good isolation Moreover, grounded stubs are used in the geometry to provide further improvement in the isolation The band rejection phenomenon in wireless local area network band is achieved by etching a C-shaped slot from the monopole of the antenna The proposed antenna has compact dimensions of $45~\hbox{mm} \times 45~\hbox{mm}$ and exhibits quasi-omnidirectional radiation pattern In addition, it shows an impedance bandwidth ( ${{\rm S}_{11}}\! ) from 2 to 106 GHz with isolation better than 17 dB over the entire ultra-wideband range Diversity performance is also evaluated in terms of envelope correlation coefficient and capacity loss The measured results show good agreement with the simulated ones

Ultralow Reflectivity Spiral Phase Plate for Generation of Millimeter-wave OAM Beam

Abstract: An ultralow reflectivity spiral phase plate (SPP) is proposed to generate an orbital angular momentum (OAM) beam at millimeter-wave frequency. The SPP is composed of unit cells whose equivalent permittivity and thickness are designed to satisfy the impedance matching condition based on transmission line theory. The designed SPP is fabricated by a 3D printing technique. The near-field and far-field phase distributions clearly exhibit the azimuth phase shifting, and the far field directivity pattern shows that the direction, gain, and 3-dB beam-width of the main lobe are about $10.5^\circ $ , 14.6 dB, and $14.5^\circ $ , respectively. Compared with no impedance-matched SPP, the reflectivity of the SPP is improved by more than 20 dB.

Compact Offset Microstrip-Fed MIMO Antenna for Band-Notched UWB Applications

Abstract: A compact multiple-input–multiple-output (MIMO) antenna is presented for ultrawideband (UWB) applications with band-notched function. The proposed antenna is composed of two offset microstrip-fed antenna elements with UWB performance. To achieve high isolation and polarization diversity, the antenna elements are placed perpendicular to each other. A parasitic T-shaped strip between the radiating elements is employed as a decoupling structure to further suppress the mutual coupling. In addition, the notched band at 5.5 GHz is realized by etching a pair of L-shaped slits on the ground. The antenna prototype with a compact size of $38.5 \times38.5~\hbox{mm}^{2}$ has been fabricated and measured. Experimental results show that the antenna has an impedance bandwidth of 3.08-11.8 GHz with reflection coefficient less than $-10~\hbox{dB}$ , except the rejection band of 5.03-5.97 GHz. Besides, port isolation, envelope correlation coefficient and radiation characteristics are also investigated. The results indicate that the MIMO antenna is suitable for band-notched UWB applications.

Dual-Band EBG Integrated Monopole Antenna Deploying Fractal Geometry for Wearable Applications

Abstract: This letter presents the design of a dual-band wearable fractal-based monopole patch antenna integrated with an electromagnetic band-gap (EBG) structure. The prototype covers the GSM-1800 MHz and ISM-2.45 GHz bands. The EBG structure reduces the radiation into the human body over 15 dB. It also reduces the effect of frequency detuning due to the human body. The performance of the antenna under bending, crumpling, and on-body conditions has been studied and presented. Specific absorption rate (SAR) assessment has also been performed to validate the antenna for its usefulness in wearable applications.

An Ultrawideband Ultrathin Metamaterial Absorber Based on Circular Split Rings

Abstract: A simple design model for making ultrawideband ultrathin metamaterial absorber has been presented in microwave frequency regime. The proposed structure is composed of two concentric circular split rings imprinted on a metal-backed dielectric substrate. A 10-dB absorption bandwidth from 7.85 to 12.25 GHz covering the entire X-band has been observed in numerical simulation under normal incidence. The absorptivities of the proposed structure have been investigated under different polarization angles as well as oblique incidence. The electromagnetic field distributions and surface current plots have been illustrated to analyze the absorption mechanism of the proposed structure. The proposed absorber has been fabricated and its performance is experimentally verified at different angles of incidence and polarizations of incident electromagnetic wave. The designed absorber is compact, ultrathin (only ${\lambda _0}/15$ thick corresponding to center frequency) and provides an alternative to construct broadband absorber for many potential applications.

Wideband RCS Reduction of a Microstrip Antenna Using Artificial Magnetic Conductor Structures

Abstract: A design approach aimed at reducing the radar cross section (RCS) of microstrip antenna in wide frequency band is proposed. First, two different artificial magnetic conductor (AMC) unit cells are designed to obtain 180 $^\circ $ ( $ \pm 30^\circ $ ) reflection phase difference over broadband frequency range. Then, chessboard configuration is structured with the two AMC unit cells and is applied to a microstrip antenna for RCS reduction. The simulated results indicate that the proposed antenna possesses remarkable RCS reduction from 8.0 GHz to 20.0 GHz for both polarizations, covering the working band of the original antenna. The maximum reduction is 31.9 dB. Moreover, the radiation performance of the antenna has been well kept. Measured results of the fabricated prototype are in good agreement with the simulations.

A Miniaturized Absorptive Frequency Selective Surface

Abstract: A miniaturized absorptive frequency selective surface (MAFSS) is presented in this letter, composed of a layer of miniaturized resistive surface placed above a metallic bandpass FSS. The MAFSS performs as a bandpass filter at operation band around 0.92 GHz, and acts as an absorber over a wide out-of-band 3–9 GHz. Moreover, due to its miniaturized elements, the MAFSS exhibits the property of eliminating the grating lobe in absorption band when illuminated by oblique incident wave. Numerical and experimental results have been given.

Crossed Dipole Loaded With Magneto-Electric Dipole for Wideband and Wide-Beam Circularly Polarized Radiation

Abstract: A crossed dipole that is loaded with a magneto-electric dipole to produce the wideband and wide-beam circularly polarized radiation characteristics is proposed. The crossed dipole is incorporated with double-printed vacant-quarter rings to feed the antenna. The antenna is backed by a metallic cavity to provide a unidirectional radiation pattern with a wide axial-ratio (AR) beamwidth and a high front-to-back ratio. Experimental results showed that the prototype with an overall size of $120\times 120\times30.5~\hbox{mm}^3$ has a $\vert { S}_{11}\vert bandwidth of 1.274–2.360 GHz and a 3-dB AR bandwidth of 1.39–1.82 GHz. The antenna showed a right-hand circular polarization (CP) radiation with a very wide 3-dB AR beamwidth ( $>165^{\circ}$ ) and a high radiation efficiency ( $ > 94\%$ ) within the operational bandwidth.

Frequency-Reconfigurable Bow-Tie Antenna for Bluetooth, WiMAX, and WLAN Applications

Abstract: A frequency-reconfigurable bow-tie antenna for Bluetooth, WiMAX, and WLAN applications is proposed. The bow-tie radiator is printed on two sides of the substrate and is fed by a microstripline continued by a pair of parallel strips. By embedding p-i-n diodes over the bow-tie arms, the effective electrical length of the antenna can be changed, leading to an electrically tunable operating band. The simple biasing circuit used in this design eliminates the need for extra bias lines, and thus avoids distortion of the radiation patterns. Measured results are in good agreement with simulations, which shows that the proposed antenna can be tuned to operate in either 2.2–2.53, 2.97–3.71, or 4.51–6 GHz band with similar radiation patterns.

An Equivalent Circuit Model of FSS-Based Metamaterial Absorber Using Coupled Line Theory

Abstract: An equivalent circuit model of an ultra-thin metamaterial absorber comprising a square-ring-shaped frequency selective surface (FSS) is presented. The model can be considered as series $RLC$ resonators connected in parallel with coupling capacitance and short-circuited transmission line. The even- and odd-mode couplings have been incorporated to accurately determine the lumped parameters as well as the absorption frequency of the absorber structure. The effects of substrate thickness and dielectric permittivity variation on the lumped parameters and full width at half-maximum (FWHM) bandwidth are investigated based on the proposed model. The absorber has been fabricated, and close matching among the calculated, simulated, and measured results has been observed.

A Compact Kapton-Based Inkjet-Printed Multiband Antenna for Flexible Wireless Devices

Abstract: A low-cost inkjet-printed multiband antenna envisioned for integration into flexible and conformal mobile devices is presented. The antenna structure contains a novel triangular iterative design with coplanar waveguide (CPW) feed, printed on a Kapton polyimide-based flexible substrate with dimensions of $ 70\times 70\times 0.11~\hbox{mm}^{\bf 3}$ . The antenna covers four wide frequency bands with measured impedance bandwidths of 54.4%, 14%, 23.5% and 17.2%, centered at 1.2, 2.0, 2.6 and 3.4 GHz, respectively, thus, enabling it to cover GSM 900, GPS, UMTS, WLAN, ISM, Bluetooth, LTE 2300/2500 and WiMAX standards. The antenna has omnidirectional radiation pattern with a maximum gain of 2.1 dBi. To characterize the flexibility of the antenna, the fabricated prototype is tested in convex and concave bent configurations for radii of 78 mm and 59 mm. The overall performance remains unaffected, except a minor shift of 20 MHz and 60 MHz in S11, for concave bending at both radii. The compact, lightweight and conformal design as well as multiband performance in bent configurations, proves the suitability of the antenna for future electronic devices.

A Palm Tree Antipodal Vivaldi Antenna With Exponential Slot Edge for Improved Radiation Pattern

Abstract: This letter presents an Exponential Slot Edge Antipodal Vivaldi Antenna (ESE-AVA), with improved radiative features as compared to the conventional Antipodal Vivaldi Antenna (AVA) design. It extends the low-end bandwidth limitation, mitigates the side and back lobe levels, corrects squint effect, and increases its main lobe gain. In order to confirm those features, a comparative study among the ESE-AVA, the low directivity conventional AVA and two popular modifications, regular slot edge (RSE) and the tapered slot edge (TSE) AVA is performed. A comparison between AVA and the proposed ESE-AVA at 6 GHz shows an improved gain of 8.3 dB, $-$ 15.5 dB of Side Lobe Level (SLL), and 0 degrees of main lobe squint (MLS), in contrast with 5 dB of gain, $ - 5~\hbox{dB}$ of SLL, and 5 degrees of MLS in the conventional AVA. By comparing the ESE-AVA with RSE-AVA and TSE-AVA, it was observed that its notches in exponential shape, similar to open the main radiator, besides mitigating the SLL also directs the E-fields distributions towards the main lobe. It reflects into a main lobe gain improvement.

Multiband Metamaterial-Loaded Monopole Antenna for WLAN/WiMAX Applications

Abstract: A simple multiband metamaterial-loaded monopole antenna suitable for wireless local area network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX) applications is proposed in this letter. The rectangle monopole of the proposed antenna is originally designed to resonate at around 5.2 GHz. When the inverted-L slot is etched, the antenna produces a second resonance at around 4.1 GHz. Then, with the addition of the metamaterial reactive loading, the resonant frequency of the antenna will be shifted down, and a third resonance covering the 2.4-GHz band occurs. Consequently, the antenna can cover the 2.4/5.2/5.8-GHz WLAN and 2.5/3.5/5.5-GHz WiMAX bands with a very compact size of only $12.9 \times 6.5~\hbox{mm}^2$ . Monopole-like radiation patterns and acceptable gains and efficiencies have been obtained. Details of the antenna design as well as the experimental results are presented and discussed.

Wearable, Small, and Robust: The Circular Quarter-Mode Textile Antenna

Abstract: A miniaturized wearable antenna, entirely implemented in textile materials, is proposed that relies on a quarter-mode substrate integrated waveguide topology. The design combines compact dimensions with high body-antenna isolation, making it excellently suited for off-body communication in wearable electronics/smart textile applications. The fabricated antenna achieves stable on-body performance. A measured on-body impedance matching bandwidth of 5.1% is obtained, versus 4.8% in free space. The antenna gain equals 3.8 dBi in the on-body and 4.2 dBi for the free-space scenario. High radiation efficiency, measured to be 81% in free space, is combined with a low calculated specific absorption rate of 0.45 mW/g, averaged over 1 g of tissue, with 500 mW input power.

A Compact Dual-Band Filtering Patch Antenna Using Step Impedance Resonators

Abstract: A compact dual-band three-pole Chebyshev filtering patch antenna with orthogonal polarizations in the two bands is developed for 2.4/5.8-GHz ISM-band applications. Step impedance resonators and aperture coupled feed techniques are integrated together to fulfill the goal. The synthesis procedure is discussed using formulation and design curves. The advantages of the proposed design, including harmonic suppression and controllable bandwidth, are verified by experiments. According to the summary table, this dual-band filtering antenna, realized in planar form, shows either a more compact size or improved radiation characteristics when compared with those reported in the open literature.

Compact Dual-SRR-Loaded UWB Monopole Antenna With Dual Frequency and Wideband Notch Characteristics

Abstract: This letter presents the design of a compact dual-split-ring-resonator (SRR)-loaded coplanar waveguide (CPW)- fed ultrawideband circular monopole antenna exhibiting dual frequency notch and wideband notch characteristics. The SRR pairs are inductively coupled to the radiator and loaded on the back side of the CPW line. Fabricated prototypes were measured and compared to simulations, and good agreement was obtained.

A Compact 2.45-GHz Broadband Rectenna Using Grounded Coplanar Waveguide

Abstract: This letter presents a compact 2.45 GHz broadband rectenna using the grounded coplanar waveguide (GCPW). A new broadband slot antenna fed by GCPW with a high gain of 10 dBi and a wide half-power beamwidth of 60 $^{\circ}$ is designed as the receiving antenna. By designing an input and an output impedance match network, a compact GCPW rectifying circuit based on the voltage doubler principle is proposed, which has broadband performance and is easy to be integrated with the novel GCPW antenna. The receiving antenna and the rectifying circuit are simulated and measured. The measured results of the rectenna agree well with those of the rectifying circuit, which validate the effectiveness of the design. The microwave-direct current (mw-dc) conversion efficiencies of the rectenna keep higher than 50% within the band from 2.2 to 2.6 GHz at 13 dBm received power on a $900\Omega $ load, and the highest efficiency is 72.5%. This rectenna has good performances of broadband, high mw-dc efficiency and compact structure.

Structure and Computationally Efficient Simulation-Driven Design of Compact UWB Monopole Antenna

Abstract: In this letter, a structure of a small ultra-wideband (UWB) monopole antenna, its design optimization procedure as well as experimental validation are presented. According to our approach, antenna compactness is achieved by means of a meander line for current path enlargement as well as the two parameterized slits providing additional degrees of freedom that help to ensure good impedance matching. For the sake of reliability, the antenna design process (simultaneous adjustment of multiple geometry parameters) is carried out using high-fidelity EM analyses. Surrogate-based optimization involving an auxiliary coarse-discretization EM model it utilized to accomplish the design in practical timeframe. Penalty function approach allows us to reduce the antenna footprint (to only $15.8 \times 22~\hbox{mm}^2$ ) while maintaining acceptable reflection in the UWB frequency range. Experimental validation of the design is also provided.

Compact All-Textile Dual-Band Antenna Loaded With Metamaterial-Inspired Structure

Abstract: A dual-band, wearable metamaterial-loaded antenna is proposed for 2.4/5.2-GHz WLAN applications. The loading is with a composite right/left-handed transmission line (CRLH-TL) metamaterial, resulting in a significant miniaturization down to ${\lambda _0}/6 \times {\lambda _0}/6 \times {\lambda _0}/20$ . Similar radiation patterns are obtained by simultaneously exciting the first-order positive ( ${ n}=+1$ ) and negative ( ${ n}=-1$ ) modes. The antenna features a low backward radiation in both bands, which is highly desirable in minimizing electromagnetic coupling to the body. The antenna is fabricated fully using textiles except for the connector and is evaluated in free space and on body, under both planar and bent conditions. Besides a good agreement between simulations and measurements, results indicate that the proposed topology is reasonably immune to body coupling and robust with respect to mechanical changes. The specific absorption rate (SAR) level is numerically investigated to determine the on-body safety level.

A Triple-Band Ultrathin Metamaterial Absorber With Wide-Angle and Polarization Stability

Abstract: This letter presents a triple-band compact and efficient ultrathin metamaterial absorber with wide-angle and polarization stability. The compact single unit cell includes a metallic background plane, four groups of dipoles lying around a metallic ring connected by four groups of pins, and only 1-mm low-cost dielectric layer. In addition, the main parameters of the designed absorber are investigated and optimized to show that each of three absorption frequency points can be effectively separately adapted, respectively. The simulation results demonstrate that this absorber has good absorption rates and polarization-insensitive characteristic over wide angles of incident waves for both transverse electric (TE) and transverse magnetic (TM) in three frequency bands. The waveguide measurement method is utilized to test the simulated results of three good absorption peaks.

A Cognitive Radio Reconfigurable MIMO and Sensing Antenna System

Abstract: A planar, compact, single-substrate, multiband, frequency-reconfigurable multiple-input–multiple-output (MIMO) antenna system is presented. The proposed antenna elements are integrated with an ultrawideband (UWB) sensing antenna to develop a complete antenna platform for cognitive radio (CR) applications. The dual-element MIMO antenna is integrated with p-i-n and varactor diodes for frequency reconfigurability. Two modes of selection are used for the MIMO antenna system reconfigurability along with varactor tuning to sweep the frequency over a wide band especially below 1 GHz. The proposed sensing antenna is used to cover a wide range of frequency bands from $720\sim3440~\hbox{MHz}$ . The complete system comprising the multiband reconfigurable MIMO antennas and UWB sensing antenna for CR applications is proposed with a compact form factor. The antenna system is developed on a single substrate area of dimensions $65\times120\times1.56~\hbox{mm}^3$ .

Millimeter-Wave Energy Harvesting Using $4\times4$ Microstrip Patch Antenna Array

Abstract: In this letter, an energy harvester at 35 GHz has been developed, which known as a rectenna. An array of a rectangular microstrip patch antenna with 16 elements was used to efficiently convert RF to dc signal. A step-impedance low-pass filter is used between the antenna and rectifier circuit to suppress second-order harmonic generated by the diode. A GaAs Schottky diode MA4E1317 was used in parallel with load as a half-wave rectifier circuit. The fabrication process is based on conventional optical photolithography to obtain an integrated circuit. The maximum RF-to-dc conversion efficiency of 67% was successfully achieved with input RF power of 7 mW at 35.7 GHz.

Broadband Circularly Polarized Patch Antenna With Parasitic Strips

Abstract: A patch antenna with parasitic strips is presented for wideband circular polarization. In order to broaden the axial-ratio (AR) bandwidth of the original corner-truncated patch, four parasitic strips are sequentially rotated and gap-coupled around the patch. A capacitive-coupled feed with a small disc on the top of the feeding probe is utilized to obtain a wide impedance-matching bandwidth. Moreover, another disc-loaded shorting pin is placed at the center of the antenna to adjust the squint beams and improve the gains along $ + z$ -axis. Measured results show that the proposed antenna with a low profile of $0.13{\lambda _0}$ obtains a global bandwidth of 24% (2.32–2.95 GHz) for $\vert{S_{11}}\vert , ${\rm AR} , and average gain of 8 dBic.

A High-Efficiency Transmitarray Antenna Using Double Split Ring Slot Elements

Abstract: This letter present a high-efficiency transmitarray antenna using a four-layer double split ring slot structure as the unit cell element. The transmission coefficient of the element at different incident angles is analyzed by Ansoft HFSS, and the results show that the element has the advantages of low transmission loss and less sensitivity to the incidence angle of the electric field. A high-efficiency transmitarray antenna composed of four layers of double split ring slot elements is designed, manufactured, and tested at Ku-band. The diameter of the transmitarray antenna is 6.76 wavelengths, and the measured gain is 23.9 dB. Radiation efficiency of 77.6% and aperture efficiency of 55% are achieved at a center frequency of 13.58 GHz in this design. The measured 1-dB and 3-dB gain bandwidths are 7.4% and 17.7%, respectively.

Frequency- and Pattern-Reconfigurable Antenna for Multistandard Wireless Applications

Abstract: A printed antenna with frequency and pattern reconfiguration is presented in this letter to meet the requirements of IEEE 802.11a/b/g/n and 802.16 standards. By controlling five p-i-n diodes, the antenna can be considered as a planar monopole or a microstrip patch and has three operation modes, i.e. an omnidirectional pattern mode at the lower frequency band of 2.21–2.79 GHz, a unidirectional pattern mode at the higher frequency band of 5.27–5.56 GHz, and both of them working simultaneously. It provides a low-profile, low-cost, and reconfigurable solution for multistandard wireless communication applications.

Implications of EMF Exposure Limits on Output Power Levels for 5G Devices Above 6 GHz

Abstract: Spectrum is a scarce resource, and the interest for utilizing frequency bands above 6 GHz for future radio communication systems is increasing. The possible use of higher frequency bands implies new challenges in terms of electromagnetic field (EMF) exposure assessments since the fundamental exposure metric (basic restriction) is changing from specific absorption rate (SAR) to power density. In this study, the implication of this change is investigated in terms of the maximum possible radiated power ( ${P_{\max}}$ ) from a device used in close proximity to the human body. The results show that the existing exposure limits will lead to a non-physical discontinuity of several dB in ${P_{\max}}$ as the transition is made from SAR to power density based basic restrictions. As a consequence, to be compliant with applicable exposure limits at frequencies above 6 GHz, ${P_{\max}}$ might have to be several dB below the power levels used for current cellular technologies. Since the available power in uplink has a direct impact on the system capacity and coverage, such an inconsistency, if not resolved, might have a large effect on the development of the next generation cellular networks (5G).

A Circularly Polarized Antenna by Using Rotated-Stair Dielectric Resonator

Abstract: In this letter, a wideband compact circularly polarized (CP) dielectric resonator antenna (DRA) is proposed. This antenna consists of two rectangular dielectric layers that are stacked with a rotation angle $\varphi $ relative to its adjacent bottom layer. The antenna is excited by an aperture coupled through a slot cutting on the ground plane. The rotated-stair configuration of DRA contributes dual broadside CP radiating modes and results in a noticeable enhancement in the axial ratio (AR) bandwidth. The proposed antenna achieves 31% impedance bandwidth and 18.2% AR bandwidth. The average gain within the AR bandwidth is 4.5 dBi with less than 0.5-dB variation. Moreover, the proposed dielectric resonator antenna has a low-profile structure. This work demonstrates a CP bandwidth broadening technique for the DRA. The potential applications of the antenna are 5G Wi-Fi and satellite communication systems.