Lower Band Edge Research Articles

Polarization-insensitive cross-polarization converter with high frequency selectivity based on an antenna-resonator-antenna module

In this paper, a novel transmission-type polarization-insensitive frequency selective polarization converter (PIFSPC) is proposed. The overall structural scheme of the proposed PIFSPC is based on an antenna-resonator-antenna (ARA) module, which is composed of a receiving patch antenna, double “S-shaped” half-wavelength resonators, and a transmitting patch antenna. By adopting cross-coupling, high frequency selectivity is achieved, and through the utilization of a staggered rotationally symmetric structure, polarization insensitivity is attained. The prototype possesses four transmission poles and two zeros on the polarization conversion spectrum, and it shows insensitivity to the polarization direction of incident electromagnetic waves. The frequency selectivity of the prototype at the lower and upper band edges is 425 dB/GHz and 283 dB/GHz respectively. The cross-polarization conversion rate (PCR) is over 95% within the passband from 4.93 GHz to 5.09 GHz for arbitrarily polarized azimuth incident waves, and its thickness is merely 0.052λ0. The operation bandwidth and frequency selectivity of the prototype can be readily altered. A prototype is fabricated and measured, with excellent consistency between simulations and experiments. It indicates the feasibility of integrating frequency selection and polarization conversion. The proposed PIFSPC has extensive application prospects in enhancing the anti-interference ability and electromagnetic compatibility in the fields of communication, measurement, and microwave detection.

Low‐profile frequency selective surface with quasi‐elliptical bandpass response using antenna‐filter‐antenna approach

AbstractAn antenna‐filter‐antenna (AFA) based frequency selective surface (FSS) with excellent spatial filtering performance is proposed. This FSS design incorporates two back‐to‐back microstrip patch antennas, which not only ensures a high roll‐off rate at the passband edge and excellent flatness within the passband, but also achieves an ultra‐low profile. Significantly, the upper and lower band edges demonstrate a substantial drop from −3 to −10 dB within the 0.006 and 0.02 GHz ranges, respectively, resulting in a sharp roll‐off skirt. Furthermore, the frequency of radiation null can be controlled by manipulating the length of the quarter‐wavelength open‐ended stub, thereby possessing exceptional out‐of‐band suppression. A prototype of the proposed FSS with low profile is fabricated and measured. The simulations and measurements of the AFA‐based FSS show that a quasi‐elliptical bandpass filtering response with superior performance is achieved.

Exploiting polarization dependence in two-dimensional coherent spectroscopy: Examples of Ce2Zr2O7 and Nd2Zr2O7

Two-dimensional coherent spectroscopy (2DCS) probes the nonlinear optical response of correlated systems. An interesting application is the study of fractionalized excitations, which are challenging to distinguish unambiguously in linear response. Here we demonstrate how the sensitivity of optical matrix elements to variations in the photon polarization allows one to probe different aspects of low-lying excitations in models of the candidate fractionalized materials Ce2Zr2O7 and Nd2Zr2O7, which host effective one-dimensional spin chains when subjected to a [110] magnetic field. We show how both fractionalized spinon excitations or conventional magnons can be picked out in the 2DCS response and how the response from polarized spin chains can be used to probe the dipolar-octupolar mixing angle θ through the relative intensity of one- and two-magnon signals. Further, we find that a [001] polarization of the probe field is particularly sensitive to lower band edge of the spinon continuum and can be used as a measure of the proximity of a quantum critical point in Ce2Zr2O7. 2DCS can thus be employed to provide invaluable and detailed information both on the constituent degrees of freedom of a quantum material and on their collective behavior. Published by the American Physical Society 2024

A compact high gain filtering patch antenna for multiband wireless system

A novel compact multilayer patch antenna is designed for triple-band operation with filtering characteristics. The multiband antenna with filtering characteristics is necessary to suppress adjacent band interference. Further, it brings higher out-of-band suppression without deteriorating the in-band gain. This filtering antenna offers size compactness, high gain, and high selectivity with reduced interference. On exciting the antenna, the electromagnetic (EM) coupling takes place from feed to patch through the slotted ground. Then the magnetic field reaches its maximum at the middle of the rectangle patch while the electric field reaches its maximum at the edges. These fields couple with the ‘U’ shaped metallic loops and bring field distribution in it and thus contribute to dual-band resonance at 2.45GHz and 4.15GHz. For better impedance matching, the two ‘U’ shaped metallic loops are employed. The additional middle band at 3.25GHz is attained through the employment of a split rectangular ring around the center patch. The bottom ground is etched with a bent horizontal slot to achieve proper positioning of the lower resonance. The modified CRLH feeding structure is adopted in this antenna to realize radiation null between operating bands. The dimension of the CRLH branches decides the positioning of radiation nulls in the spectrum of interest. This null reduces the interband interference and it is an important feature for any multiband communication system. The usage of via between patch and feed increases the electrical length of an antenna and thus provides size miniaturization. Whereas the position of the via in the patch decides the impedance matching. thus multiple iterations of simulation were done to optimize the via position for better impedance matching. The designed antenna has a compact dimension of 0.21λo × 0.21λo. The realized triple bands have −10dB impedance bandwidth of 180MHz (2.31 to 2.49GHz), 350MHz (3.1 to 3.45GHz), and 850MHz (3.6 to 4.45GHz) with a maximum gain of 5.2dB. Thus the multi-layer antenna not only has proven to be multiband but also incorporated filtering characteristics to lessen interband interferences. The proposed antenna would be beneficial in a multiband wireless system that supports services such as Wifi, WiMAX, and 5G. The antenna is the perfect candidate for the unmanned ariel vehicle (UAV) to be used in emergency and military applications.

Merging and Band Transition of Bound States in the Continuum in Leaky‐Mode Photonic Lattices

AbstractBound states in the continuum (BICs) theoretically have the ability to confine electromagnetic waves in limited regions with infinite radiative quality (Q) factors. However, in practical experiments, resonances can only exhibit finite Q factors due to unwanted scattering losses caused by fabrication imperfections. Recently, it has been shown that ultrahigh‐Q guided‐mode resonances (GMRs), which are robust to fabrication imperfections, can be realized by merging multiple BICs in momentum space. This study analytically and numerically investigates the merging and band transition of accidental BICs in planar photonic lattices. Accidental BICs can merge at the edges of the second stop band, either with or without a symmetry‐protected BIC. The results show that as the thickness of the photonic lattice gradually increases, the merged state of BICs transitions from the upper to the lower band edge. Using coupled‐mode analysis, the analytical merging thickness at which multiple accidental BICs merge at the second‐order Γ point is presented. The coupled‐mode analysis can be beneficial for achieving ultrahigh‐Q GMRs in various photonic lattices composed of materials with different dielectric constants.

Design of Linear Magnetic Field Sensor Based on Periodically Magnetized Cold Plasma

We have analyzed the impact of a linear magnetic field on the photonic band gaps exhibited by bulk cold plasma, under external square-wave-like periodic magnetic field of fixed magnitude, conceived as an extrinsic photonic crystal. Here photonic band gaps are determined using transfer matrix method (TMM). Here, the impact of an additional linear magnetic field is determined on the band gaps of plasma photonic crystal with constant magnitude of square like periodic magnetic field, for normal incidence. We determine how the additional and magnetic magnetic field affects the photonic band structure (PBS) and reflectance for such extrinsic photonic crystal. It is noted that, as we increase the additional applied magnetic field, the central frequency of band gaps is shifted toward higher frequency regions in GHz. The band edge increases linearly with the applied magnetic field. The shifting in lower band edge less as compared to upper edge. Sensor is a device which detect the stimuli and give output, and many physical parameters can be measured by sensors. The shifting of band edges can be utilized in design of magnetic field sensor. Here shifting in band gaps by variation in the additional applied magnetic field are determined. The larger value of sensitivity gives a good result for sensing-based application. This analysis is based on the band gaps of extrinsic photonic crystal, and can be employed in design of magnetic field sensor with good sensitivity. Moreover, it can find applications in tunable optical devices.

A quadband polarization insensitive and angularly steady frequency Selective surface for gain enlargement of multiband antenna

A simply constructed bi-layered compact Frequency Selective Surface (FSS) is reported in this article to attain four distinct stop bands for multiband wireless applications. The compact FSS consists of complimentary oriented repeated cells in top and bottom layers with cell size of 0.135λL × 0.135λL and 0.12λL × 0.12λL respectively where λL refers the lower band edge wavelength. The FSS exhibits bi-polarized characteristic with angular steadiness till 450 in TE and 300 in TM polarization. The FSS, act as a sub-reflector to broaden the antenna gain, is placed beneath a simple co-planar waveguide (CPW) fed quadband antenna having three triangular patches with rectangular slots stacked together. This united ‘antenna-FSS’ structure attained S11 < -10 dB spectrums at 3.1–3.7 GHz (17.65 %), 5.3–6 GHz (12.34 %), 9.7–11.72 GHz (18.86 %) and 17.4–19.15 GHz (9.57 %) as per experimental evaluation. The ‘antenna-FSS’ offers maximum gain value 9.56 dBi with an enlargement of 4.9 dBi, 3.7 dBi, 4.3 dBi and 5 dBi in its four bands. Adequate radiation efficiency, linear transfer function response and smooth group delay contour are also conquered from ‘antenna-FSS’ in its four bands. The reported ‘antenna-FSS’ is appropriate for multiband wireless technologies as it covers WiMAX, WLAN, ISM, terrestrial and satellite spectrums.

Investigation on Self-Excited Oscillation for Nonuniform Periodic Sheet Beam Traveling-Wave Tubes

The utilization of phase velocity tapering or jumping techniques in the design of traveling wave tubes (TWTs) has become a widely accepted practice for enhancing the efficiency of beam–wave interaction. However, these approaches are not without their challenges, as they can lead to a series of self-excited oscillation (SEO) issues that restrict further improvement in power. In this article, a nonlinear numerical method is explored for fast prediction of SEO in nonuniform periodic sheet beam TWTs (NP-SBTWTs). The oscillation thresholds at the upper and lower band edges are analyzed and discussed under different voltage and current conditions to determine the stable operating conditions for NP-SBTWT. In addition, the concept of “sideband absolute self-excited state” is proposed to be avoided in dispersion design, and the impact of actual reflection characteristics on stability is quantified by defining the eigenvalues of the feedback gain of the interaction structure based on the real reflection parameter. The results demonstrate that this approach distinguishes itself from conventional time-domain particle-in-cell (PIC) simulation techniques by its capacity to integrate authentic reflection parameters into the computation process to achieve a fast prediction of SEO in NP-SBTWT.

Design and Optimization of a High-Gain Filtering Antenna Based on Parasitic Pixel Layer

A novel high-gain filtering antenna based on the parasitic pixel layer is designed and optimized in this paper. Initially, a circular patch surrounded by a shorted concentric annular ring one is proposed as the radiation source, such a design is able to realize an upper radiation null. Afterward, a parasitic pixel layer is placed upon the radiation source with an air gap. Another radiation null at the lower band is then obtained by optimizing the connection status between adjacent pixel elements based on the internal multi-port method. Besides that, the parasitic pixel layer can enhance the realized broadside gain. Finally, a high-gain filtering antenna with a bandpass response is obtained. The antenna is validated by a full-wave simulation study followed by the experimental verification. Measured results indicate that the antenna can operate from 4.7 to 5.4 GHz with an average gain of 9.6 dBi and two radiation nulls at the lower and upper band edges of the reflection coefficient curve.

Research on the vibration characteristics of an embedded elastic metamaterial plate

For a class of embedded elastic metamaterial plate, a general vibration analysis process is given based on the idea of equivalent analysis, which combines the equivalent medium theory and the classical thin plate vibration theory. The embedded elastic metamaterial plate is treated as an equivalent homogeneous plate with abnormal effective medium parameters by using the equivalent medium theory, and then the natural vibration characteristics and steady-state vibration characteristics are investigated. The results show that the semi-analytic form of the vibration analysis process is effective, which can obtain the vibration characteristics of such heterogeneous and complex structures quickly and accurately within the medium and low frequency regions. The results also reveal the plate’s anomalous behaviors that are quite different from the traditional homogeneous plates. For the natural vibration, there exists no natural frequency in the band gap and they can be formed only in the pass band. These modes tend to gather gradually when approaching the initial frequency of the band gap, and the closer to the lower band edge of the band gap, the smaller the distance between natural frequencies and the greater the modal density. Additionally, the modes of the corresponding orders before and after the band gap are identical on the macro level but completely different on the unit-cell level. For the steady-state vibration, there is no resonance peak in the band gap, the resonance peaks are distributed denser and denser when approaching the initial frequency of the band gap, and the distribution of the displacement field at corresponding order of resonance peaks before and after the band gap is also similar on the macro level. This work not only facilitates the design and analysis of elastic metamaterial plate structures, but also deepens the understanding of their extraordinary vibration characteristics and expands the design space of mode characteristics.

Design of a Circuit-Free Filtering Metasurface Antenna Using Characteristic Mode Analysis

This communication presents a method of designing filtering metasurface (MTS) antennas, which is to excite the candidate in-band modes and suppress the out-of-band interference ones. The candidate modes are selected depending on the expected radiation patterns and operating band and excited by choosing a reasonable feeding structure. The suppression of interference modes is achieved by controlling the modal currents with the aid of a characteristic mode analysis (CMA). As a result, the MTS works as a radiator and a filter simultaneously. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times3$ </tex-math></inline-formula> array MTS antenna is implemented to demonstrate the concept. Targeting the broadside radiation pattern and 5G operating band, two candidate MTS modes are selected. A ground slot is used to excite them and introduce an extra slot mode. The out-of-band interference modes are eliminated by removing specific patches and etching a split slot on the central patch of the MTS. Moreover, to improve the selectivity at the lower band edge, a probe is added at the center of the antenna. The antenna has a simulated −10 dB impedance bandwidth of 25%, covering the 5G n77 band (3.3–4.25 GHz). The out-of-band suppression level exceeds 27 dB. Thin-band peak gain is 10.9 dBi, while the peak efficiency reaches 95%.

Tunable Topological Acoustic Tamm States in Comblike Structures Based on Band Inversion around Flat Bands

We investigate the existence of acoustic Tamm states at the interface between two one-dimensional (1D) comblike phononic crystals (PnCs) based on slender tubes and discuss their topological or trivial character. The PnCs consist of stubs grafted periodically along a waveguide and the two crystals differ by their geometrical parameters (period and length of the stubs). We use several approaches to discuss the existence of Tamm states and their topology when connecting two half-crystals. First, we derive a necessary and sufficient condition on the existence of interface states based on the analysis of the bulk band structure and the symmetry of the band edge states. This approach is equivalent to an analysis of the Zak phases of the bulk bands in the two crystals. Indeed, a topological interface state should necessarily exist in any common bandgap of the two PnCs for which the lower (upper) band edges have opposite symmetries. A novelty of our structure consists in the fact that the symmetry inversion results from a band closure (flat band) rather than from a gap closure, in contrast to previous works. Then, such interface states are revealed through different physical quantities, namely: (i) the local density of states (LDOS), which exhibits a high localization around the interface; (ii) sharp peaks in the transmission spectra in the common bandgap when two finite crystals are connected together; (iii) the phases of the reflection coefficients at the boundary of each PnC with a waveguide, which have a direct relationship with the Zak phases. In addition, we show that the interface states can transform to bound states in the continuum (BICs). These BICs are induced by the cavity separating both PnCs and they remain robust to any geometrical disorder induced by the stubs and segments around this cavity. Finally, we show the impossibility of interface states between two connected PnCs with different stub lengths and similar periods. The sensitivity of these states to interface perturbations can find many practical applications in PnC sensors.

Theoretical study on the photocatalytic potential of BSe nanotubes for water splitting under visible light

Photocatalytic splitting of water has been a useful tool in recent years for solving the world's energy and environmental problems. However, the wide band gap and low carrier mobility of traditional photocatalysts are the reasons that limit their wide application. In this work, the structure, and optical properties of BSe nanotubes are studied for the first time based on density functional theory.The results show that single-walled BSe nanotubes (SW BSe NTs) not only have a stable structure but can also extend the ultraviolet light absorption range of the BSe monolayer to the visible light range. Significantly, the SW BSe NT has excellent photoreduction ability, low electron-hole recombination rate, and high hole carrier mobility (∼103 cm2V−1s−1). Under uniaxial strain, the SW BSe NT exhibits a direct-indirect band gap transition. Furthermore, the electronic structure of double-walled BSe nanotubes facilitates charge separation and has a wider range of light absorption. Unluckily, its lower band edge position prevents it from having an overall photocatalytic decomposition capability. Our results show that SW BSe NTs have potential applications in visible light-driven photocatalytic water splitting.

The influence of printing accuracy on the performance of additively manufactured AlSi10Mg phononic crystals

The printing accuracy is one of the key factors affecting the final additively manufactured structures. As metamaterials for wave controlling, the printing accuracy caused in additive manufacturing can affect the band gap structures and the wave transmissions in phononic crystals (PnCs). Selective laser melting (SLM) was used to fabricate the designed PnCs. AlSi10Mg was used as the material for the fabrication. The distorted geometry of the additively manufactured PnCs by selective laser melting (SLM) was experimentally measured and then was re-built as finite element model. The band gap structures and the wave transmissions were calculated based on finite element method for the comparison of the structural performances of the theoretically designed and fabricated PnCs. Result indicated that the fabricated PnCs were thermally distorted from 0.298 mm to 1.664 mm depending on the designed geometries. The thermal distortion can lead to a deviation of central frequency in the range of −6.2%∼3.7% in comparison with the theoretical design. Compared with the theoretical design, the band gap widths of the distorted PnCs vary from −7.4% to 5.6% due to the frequencies change of the eigenmodes at the upper and lower band edges which are directly affected by the thermal distortion. The further analysis shows that the change of the band structures of the distorted PnCs is due to the increase of the inertia moment of the distorted PnCs caused by the printing accuracy.

Low Profile Reflective Polarization Conversion Metasurface With High Frequency Selectivity

In this article, a multilayer reflective polarization conversion metasurface with both high-frequency selectivity and low profile is proposed. The frequency selective polarization conversion metasurface (FSPCM) is composed of four metal layers separated by three substrates. The cross-shaped patch on the top layer is connected to the folded microstrip line on the bottom layer with two via holes through the circle slots inside two ground layers, which converts the linearly polarized electromagnetic incident wave into cross-polarized wave after reflection. The second-order response can extend to the third-order response by introducing a coupled half-wavelength microstrip resonator on the bottom metal layer, which achieves high-frequency selectivity with a transmission zero and high polarization conversion rate (PCR) without increasing the thickness. The equivalent circuit analysis, structure simulation, and experimental demonstration are conducted in detail; the frequency selectivity of the fabricated FSPCM at the lower and upper band edge is 94 and 192 dB/GHz, respectively; PCR is more than 97% from 4.85 to 5.12 GHz, and the thickness is only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.028\lambda _{0}$ </tex-math></inline-formula> , where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the free space wavelength at the center operating frequency. Our findings pave a new way for enhancing the anti-interference capability and electromagnetic compatibility in applications of communication system, microwave imaging, and stealth technology.

Increasingly Accurate Stability Study of the Experimental W-Band TWT Using Code TESLA-Z Stability Analysis Framework

We present the results of our comprehensive numerical stability study of the experimental, high-power, two-stage Serpentine <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${W}$ </tex-math></inline-formula> -band traveling-wave tube (TWT) with ~10% working bandwidth. This device demonstrated an output power level of ~215 W at 92 GHz at the nominal beam voltage of 20 kV and ~285 W at an increased beam voltage of 20.8 kV. The experimental device was observed to be stable in all cases when operated within the designed beam voltage range. The onset of instability near the lower band edge was observed at higher beam voltages approaching a threshold value of ~21.0 kV. We use the recently developed stability analysis framework, based on the Naval Research Laboratory (NRL) 2-D large-signal code TESLA-Z, to find the predicted threshold of zero-drive instabilities, which could develop near the lower band edge of the experimental <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${W}$ </tex-math></inline-formula> -band TWT. An initial study was done by using a simplified model for geometry of the experimental electrodynamic structure of the TWT, which ignored all interface elements. TESLA-Z predictions for onset of instability, in this case, were found much higher in beam voltage than its measured value. Next, an advanced TESLA-Z-based stability study was performed using a more accurate, detailed model for geometry of the experimental electrodynamic structure of the TWT, including important elements such as couplers (transformers), lossy load (sever), and windows. This more detailed analysis gave more accurate results for the onset of instability, in good agreement with the measurements.

Performance of photocatalytic, carbonated calcium sulfoaluminate-belite cement

Carbonated and non-carbonated paste samples containing white Ordinary Portland Cement (OPC) or Calcium Sulfoaluminate-Belite (CSAB) cement with TiO2 were evaluated for NOx removal, optical properties, and CaCO3 polymorphs using chemiluminescence NOx analyzer, UV-Vis-NIR spectrophotometer, and X-Ray Diffraction, respectively. NOx removal of photocatalytic CSAB cement was 43% and 28% lower than white photocatalytic cement for non-carbonated and carbonated samples, respectively. Partially replacing the cements with fly ash decreased NOx removal in the non-carbonated state but reduced the negative impact of carbonation on photocatalytic efficiency. The decrease in NOx removal of carbonated samples were a combination of decrease in surface porosity, coverage of TiO2 sites by carbonation products, and decrease in activated TiO2 sites caused by a lower average diffuse reflectance in UV-A region despite an increase in photoconductance. All the TiO2-doped paste had a lower band edge energy than pure nano TiO2, and Urbach absorption tail, indicating presence of localized defects.

A Low-Cost High-Gain Filtering Patch Antenna With Enhanced Frequency Selectivity Based on SISL for 5G Application

This letter presents a high-gain filtering antenna with multiple radiation nulls and enhanced frequency selectivity using substrate integrated suspended line (SISL) technology. The presented antenna is composed of driven patches with slots, parasitic units, stubs, and stacked patches. The first radiation null is caused simultaneously at the upper band edge when the stacked patches are introduced to produce a resonance mode. The second radiation null is produced by the slots on the driven patches at the lower band edge. Due to the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> mode of the driven patches, the third radiation null is introduced at higher frequency. Owing to the stubs and parasitic units, the fourth radiation null is caused at lower frequency. The above four radiation nulls achieve excellent filtering performance with high selectivity. The measured results indicate the outstanding performance of the filtering antenna. The passband is from 3.28 to 3.79 GHz, perfectly covering the 5G-N78 band. The peak gain reaches 11.14 dBi, and the out-of-band rejection level is 17.8 dB. In addition, this filtering patch antenna is designed based on low-cost substrate FR4.

A Simple Wide-Angular Scanning Phased Array With Wideband Filtering Response

This article presents a low-profile planar phased array with improved reflection (wideband filtering response) and radiation (wide-angular scan) performance. On one hand, the filtering response with harmonic suppression is integrated into the design of the single-layer array element without extra filtering resonators, such as external filters. As a result, the designed array possesses a reflection bandwidth of 4.6–5.3 GHz and two radiation nulls at either the upper or lower band edge of the reflection curve. On the other hand, inspired by the wide-beam radiation of a circular patch loaded with parasitic monopoles, the proposed array is able to realize its beam scanning coverage of −60°–+60° with low sidelobe levels (SLLs) in its E-plane. The reflection and radiation properties are validated by full-wave simulation and measurement of an eight-element array prototype. The filtering and low-SLL performance benefit for the array to avoid out-of-band interferences and in-band ones from other directions when it scans in a wide-angular area.

Design of Filtering Dielectric Resonator Antenna Arrays Using Simple Feeding Networks

A 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 3 filtering dielectric resonator antenna (DRA) array is investigated in this communication. The central DRA is excited by a microstrip-coupled slot, while the two side DRA elements are, respectively, excited by the central DRA via a low-profile patch-loaded dielectric bridge laid between them. In order to integrate the filtering function, the open stub of the microstrip feed line is elaborately designed to generate a radiation null at the upper band edge, while two vertical metallic strips are added onto the sidewalls of the central DRA to provide another radiation null at the lower band edge. On the other hand, in order to achieve an enhanced gain in the operating passband, the higher order TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">113</sub> mode of the DRA elements is excited. It is found that due to the loading effects of metallic patches and conformal strips, three stepping resonances of the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">113</sub> mode are generated in the passband, leading to a wide impedance bandwidth of 13.7% and a stable gain of 11.4 dBi. As a result, both good radiation and filtering performance are achieved without requiring complex filtering circuits. To demonstrate the extensibility of the array, a larger 3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 3 filtering DRA array with a high peak gain of 14.7 dBi is further designed by just using a three-way power dividing network.