Dual-beam Radiation Research Articles

A Wideband Millimeter-Wave Dual-Beam Dielectric Resonator Antenna with Substrate Integration Capability.

A wideband dual-beam dielectric resonator antenna (DRA) with substrate integration capability was proposed for millimeter-wave (mm-wave) applications. The four rows of air vias along the x-direction and two extended rectangular patches could shift the undesirable radiation mode upward and move the conical-beam radiation mode downward, respectively. Thus, the TE211 mode and the TE411 mode of the patch-loaded perforated rectangular substrate integrated dielectric resonator (SIDR) supporting the dual-beam radiation can be retained in the operating band, and their radiation can be improved by the air vias along the y-direction. The T-shaped line coupled dual-slot structure could excite the above two modes, and a dual-slot mode supporting dual-beam radiation could also work. Then, a wideband DRA with a stable dual-beam radiation angle can be achieved, and its impedance matching can be improved by two air slots on two sides. Compared with the state-of-the-art dual-beam antennas, the proposed antenna shows a wider bandwidth, a higher radiation efficiency, and the substrate integration capability of DRA, making it more suitable for mm-wave applications. For demonstration, a 1 × 4 array was designed with the 10 dB impedance matching bandwidth of 41.2% and the directions of the dual beams between ±30° and ±35°.

Design of a 3-Bit Circularly Polarized Reconfigurable Reflectarray

In this paper, a 3-bit circularly polarized reconfigurable reflectarray is proposed. The array consists of 64 units in an 8 × 8 configuration, with each unit containing a circular metal patch loaded with phase-delay lines and eight PIN diodes. To independently control each unit, a corresponding DC control circuit was designed and tested with the array. In the bandwidth of 3.43–3.71 GHz, the circularly polarized reconfigurable reflectarray achieved a gain of 16 dB, an aperture efficiency of 27%, an axial ratio of ≤3 dB, an operating bandwidth of 8%, and a beam scanning range of ±60°. The circularly polarized reconfigurable reflectarray can also achieve a good dual-beam radiation performance after testing. The 3-bit circularly polarized reconfigurable reflectarray proposed in this paper offers several advantages, including low loss, high aperture efficiency, a wide beam scanning range, and excellent stability in wide-angle oblique incidence. It has potential applications in low-cost phased array, satellite communications, and deep space exploration.

Endfire Substrate Integrated Dielectric Resonator Antenna With Dual-Beam Radiation for Millimeter-Wave Application

Endfire Substrate Integrated Dielectric Resonator Antenna With Dual-Beam Radiation for Millimeter-Wave Application

In-situ TEM investigation of zirconium alloy under Kr+ single-beam and Kr+-He+ dual-beam synergetic irradiation

The in-situ TEM irradiation experiments of zirconium alloy were conducted at 573 K, 673 K, and 773 K utilizing a 400 keV Kr + single beam and a 400 keV Kr+ and 30 keV He + dual beam. The results show that a large number of dislocation loops have been characterized in the matrix of the zirconium alloy under irradiation. With increasing the irradiation damage dose, some dislocation loops have reacted with one another to form a larger dislocation loop, which has finally formed dislocation lines or other defect structures. In zirconium alloys irradiated with Kr + single beam and Kr+ and He + dual-beam radiation, the proportion of <a> type dislocation loops with different Burgers vectors is essentially the same at low damage doses, but the proportion of interstitial type dislocation loops with the same Burgers vectors is obviously different. The amorphization of the second phase and the dissolution of the small-sized second phase were also pointed out. With the increase in temperature, the density of the dislocation loop in zirconium alloy gradually decreases, and the size of dislocation loop first increases and then decreases. Kr+ and He + dual beam irradiation increases the size of dislocation loops but decreases their density as compared with Kr + single beam irradiation.

Design and Optimization of Metamaterial-Based 5G Millimeter Wave Antenna for Gain Enhancement

In this brief, a low profile, broadband, high-gain antenna array based on optimized metamaterials (MMs) with dual-beam radiation is reported for 5G millimeters wave (mm-wave) applications. The design is a simple bow tie operating at a 5G band of 28 GHz. It consists of two bow ties with substrate integrated waveguide (SIW)-based power splitter. A broad impedance bandwidth of 26.3.29.8 GHz is obtained by appropriately combining the resonances of the bow ties and the SIW. Further, the antenna exhibits symmetrical dual-beam radiation at ±25∘ over a broad bandwidth in the end-fire direction due to the arrangement of the two radiators. A MM array has been etched in the same substrate shared with the antenna to improve the gain performance while preserving compact size. The trust-region (TR) gradient-based algorithm is used to optimize the structure dimensions and to achieve a maximum gain of 12.2 dB at 29 GHz. The developed MM-based antenna is validated experimentally with a good matching between the simulated and measured data. The system features a small size, low profile, high gain, broad bandwidth, and dual-beam in the E-plane, demonstrating its suitability for 5G mm-wave indoor scenarios.

Design Approach for Pattern-Reconfigurable Patch Antenna Without Extra Feeding Networks

In this communication, an efficient approach with multiple loading techniques is proposed to design a low profile, single-fed, pattern reconfigurable patch antenna with broadside and dual-beam radiation patterns. Initially, a transmission-line model is developed to theoretically investigate the resonant frequency of a rectangular patch antenna with radiation efficiency ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\eta _{r}$ </tex-math></inline-formula> ) into consideration as well. It is revealed that the frequency overlap in the two states without significantly sacrificing <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\eta _{r}$ </tex-math></inline-formula> can be achieved by properly loading shorting pins and open-ended stubs. Besides, the two center-loaded elements, i.e., a shunt capacitor and a series inductor, are also studied for demonstration of their unique effects on impedance matching for both states or operating modes. Then, a design guideline is summarized based on the theoretical analysis. Following the developed guideline, two examples working at the same operating frequency of 2.45 GHz are designed, fabricated, and tested. Measured gains of 9.6 (8.7) and 5.6 (5.3 dBi) of antenna example A (example B) are obtained for broadside and dual-beam modes, respectively. The measured and simulated results are observed in good agreement, thereby demonstrating the validity of the proposed scheme. The merits of low profile, high gain, and no need of extra feeding networks make the proposed antennas good candidates for modern communication systems.

AnEH2‐mode microstrip leaky‐wave antenna with single beam radiation and backward‐to‐forward scanning

In this work, a leaky-wave antenna (LWA) based on the second higher-order-mode (EH2-mode) microstrip line is proposed for achieving the backward-to-forward beam scanning and single main beam radiation. The original microstrip EH2-mode LWA inherently radiates two symmetric beams in the transversal plane. By loading a series of longitudinal slots, the dual-beam radiation of the antenna is converted into single-beam radiation. To achieve the continuous beam scanning, a series of transversal slots are further etched at each periodic cell correspondingly, where the frequency balanced condition could be satisfied for suppressing the open-stop band. Finally, a prototype of the proposed EH2-mode LWA is designed, implemented and fabricated. The measured results agree well with those results obtained from the simulation, validating the proposed method of single-beam radiation and OSB suppression. The designed antenna in the measurement can scan from −15° to +15° with the frequency varying from 4.7 to 5.4 GHz.

A Compact Low-Profile Antenna for Millimeter-Wave 5G Mobile Phones

This paper presents a very low profile and simple antenna design for dual beam and dual-band operation to be employed in future 5G mobile phones operating in the millimeter-wave bands of 26.75–30.31 and 35.83–41.22 GHz. The two distinct resonances at 28 and 38 GHz are achieved using a meta-material-based structure consisting of a closed-ring resonator (CRR) and a split-ring resonator (SRR) by co-centrically combining two planar hexagonal rings; i.e., an inner split-ring resonator (SRR) and an outer closed-ring resonator (CRR). The antenna has a high gain of 4.5 dBi. The antenna also exhibits a dual-beam radiation pattern in one of its planes. The overall antenna size is 6 × 8 mm2 and is manufactured using a low-cost PCB fabrication process. The antenna’s dual-beam operation, broadband characteristics, high gain, and low profile makes it a potential candidate for future millimeter-wave mobile phones, especially in applications where space diversity is required.

Systematic Design of a Holographic-Based Metasurface Reflector in the Sub-6 GHz Band

This letter presents a systematic method to regulating the response of an artificial impedance surface. The method is based on governing the dispersion diagram to control the depth of modulation so that a meaningful pattern of scatterers is obtained on the structure. The method is applied on a holographic-based large reflective metasurface to achieve a dual-beam radiation pattern with tilt angles of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm 45^{\circ }$</tex-math></inline-formula> in the azimuth plane at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$f=3.5$</tex-math></inline-formula> GHz. The structure is fabricated and the measured data concur with the simulation results.

Single-Feed Multibeam Conformal Transmitarrays With Phase and Amplitude Modulations

Single-feed multibeam conformal transmitarrays using a superposition method are presented in this letter. The arrays consist of ultrathin Huygens elements with independent amplitude and phase manipulations. Three cylindrical conformal transmitarrays with dual-beam radiation patterns are designed at 10 GHz, producing dual beams at ±30°, +30°, and −20°, +30° and −10°, respectively. As an experimental validation, the prototype with symmetrical dual beams is fabricated and measured. Two beams at +29° and −28° along the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> -plane are achieved with a measured 18.29 dBi peak gain. The gain difference between the two beams is 0.13 dB. Good agreement between simulation and measurement is observed.

Low-Profile High-Directivity Dual-Beam Circularly Polarized Antennas Under Operation of Two Odd Modes

In this article, two coupled patch radiators are intensively investigated to characterize two pairs of even/odd modes by virtue of characteristic modes analysis (CMA). It is discussed that both radiation patterns and characteristic angles (CAs) of the two orthogonal odd modes are critical factors in the design of dual-beam circularly polarized (CP) antennas. However, neither of them could be correctly derived from a two-element-array model. By adjusting resonant frequencies (ResFs) in different ways, the two odd modes could achieve a 90° difference in CA. Moreover, the two odd modes have similar dual-beam radiation patterns with peak values in the same vertical plane. By further effectively exciting the two odd modes and fully suppressing the two even ones, four CP dual-beam patch antennas are successfully designed. Both simulated and measured results validate the effectiveness of the proposed technique in the design of low-profile high-directivity dual-beam CP patch antennas. It is also discussed that the pointing angle of dual-beam could be reduced by enlarging patch distance or utilizing higher-order odd modes, while the axial-ratio (AR) bandwidth could be improved by increasing substrate height or introducing a broadband feeding network.

A Dual-Beam Wideband Filtering Patch Antenna With Absorptive Band-Edge Radiation Nulls

A dual-beam filtering patch antenna with two absorptive band-edge radiation nulls and four reflective stopband radiation nulls is proposed. By loading a pair of T-shaped metallic strip underneath the radiating patch, a modified TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sub> mode with TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> -like radiation pattern is obtained, which combines with 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 radiating patch, generating a wide operating band with symmetrical dual-beam radiation pattern. Two reflective radiation nulls are generated in both upper and lower stopbands for suppressing the out-of-band radiation. Through embedding two pairs of shorted small patch in the radiating patch, one absorptive radiation null combining with one absorptive resonant mode is produced at each band edge to absorb the band-edge incident energy, leading to a reduced reflection and sharp roll-off at both band edges, and therefore, the transceiver can be protected. With a total height of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.038~\lambda _{0}$ </tex-math></inline-formula> , a prototype is designed, fabricated, and measured, showing a −10 dB impedance bandwidth from 4.63 to 6.10 GHz with sharp band-edge roll-off, two radiation beams directed at ±40° with an in-band gain of 6.0 dBi, and high out-of-band suppression of over 15 dB.

A dual-beam lens-free slot-array antenna coupled high-T c superconducting fundamental mixer at the W-band

This paper presents a W-band high-T c superconducting (HTS) Josephson-junction fundamental mixer which is coupled using a dual-beam lens-free slot-array antenna. The antenna features a uniplanar six-element slot array fed by an ungrounded coplanar waveguide line, of which each element is a long slot loaded by four rectangular loops. Highly directional radiation is therefore realized by utilizing the long slots and array synthesis to form a relatively large antenna aperture. The antenna also enables asymmetric dual-beam radiation in opposite directions, which not only reduces the RF coupling losses but greatly facilitates the quasi-optics design for the integration of the HTS mixer into a cryocooler. The electromagnetic simulations show that a coupling efficiency as high as −2.2 dB, a realized gain of 13 dB and a front-to-back ratio of 10 dB are achieved at the frequency of 84 GHz. Using this on-chip antenna, a W-band HTS fundamental mixer module is experimentally developed and characterized for different operating temperatures. The measured conversion gain is −10 dB at 20 K and −14.6 dB at 40 K, respectively. The mixer noise temperature is predicted to be around 780 K at 20 K and 1600 K at 40 K, respectively. It is also analyzed that the mixer performance can be further improved if the Josephson junction parameters were optimized.

Square-Framed T Shape mmwave Antenna Array at 28 GHz for Future 5G Devices

In this research, a novel T shape antenna is proposed for millimetre-wave (mmwave) 5G systems. Designed on 0.254 mm thin Roggers 5880 substrate with a dielectric constant of 2.3 and the loss tangent of 0.0009, the proposed antenna offers a wideband characteristics of nearly 8 GHz with gain of 4.25 dBi for single element. Based on these characteristics, the single element is further constructed into a four-element linear array with a compact size of 18.5 × 24 mm2 The proposed antenna array exhibited dual beam radiation patterns with a high realized gain of 11.5 dBi and 94% efficiency. The measured results from the fabricated prototype well agree with the simulated results and thus, therefore, make the proposed antenna system a well-suited candidate for future mmwave devices.

A broadband reconfigurable antenna with parasitic water radiation Array

This article introduces a wideband pattern reconfigurable antenna made of seawater. A special funnel-shaped metal structure is used for feeding to increase the bandwidth of the antenna. The antenna-design refers the electronically steerable parasitic array radiator antenna principle, and arc-shaped water columns are introduced around the seawater monopole antenna to operate as parasitic passive oscillators. These parasitic elements turn the omnidirectional antenna into a directional antenna. The proposed antenna has more than one mode. When the number of parasitic elements is 2, 3, and 4, it respectively corresponds to three different working modes: dual-beam radiation, wide-angle radiation, and directional high-gain radiation. And in all these three modes, changing the position of the parasitic elements can achieve 360° beam-sweeping in the 1.66 ~ 2.78 GHz. A prototype is fabricated and verified, and the experimental results are in good agreement with the simulated results. The antenna is filled with seawater when in use, and the weight can be reduced by draining the seawater when not in use. There is great application potential in the field of maritime communications.

A low‐profile dual‐band shorted patch antenna with enhanced‐bandwidth and multifunctional beams under reshaped modes

A low-profile dual-band shorted patch antenna (SPA) with bandwidth-enhancement and multifunctional beams is proposed in this article. Initially, the radiation patterns of the traditional SPA are extensively studied. It demonstrates that the radiated fields of its TM1/2,0, TM3/2,0, and TM3/2,1 modes are unsuitable to be employed for multibeam radiation. As such, a pair of shorting pins2 is loaded underneath the radiating patch, aiming to transform the broadside-beam of TM1/2,0 mode into the dual-beam. After that, a set of shorting pins3 is placed to reshape radiated fields of its TM3/2,0 and TM3/2,1 modes as the dual-beam and broadside-beam, respectively. Meanwhile, the resonant frequencies of its TM1/2,0 and TM1/2,1 modes are reallocated closely to that of TM3/2,0 and TM3/2,1 modes. With these arrangements, both of impedance bandwidth and radiation beams are enhanced under quadruple-mode resonance. Finally, the proposed SPA is fabricated and measured. The results illustrate that the microstrip patch antenna has successfully obtained an enhanced-bandwidth (|S11< −10 dB) ranging from 4.0 to 4.29 GHz and 5.24 to 5.77 GHz with two in-band attenuation poles. Besides, a small thickness of about 0.04 free-space wavelength is still maintained, while keeping single-layer and single-fed properties. Most importantly, the proposed SPA has generated desired broadside−/dual-beam radiation patterns over the operating bands.

Theory, Design, and Verification of Dual-Circularly Polarized Dual-Beam Arrays With Independent Control of Polarization: A Generalization of Sequential Rotation Arrays

In this article, the theory, design, and validation of planar array antennas capable of producing dual-circularly-polarized (dual-CP) dual-beam radiation with a single feeding network are reported. Importantly, the properties of the formed CP beams with different handedness can be independently controlled. Such a capability is achieved by exploiting both the in-plane rotation-induced Berry phase and excitation phase for all the linearly polarized array elements, which can be regarded as a generalization of the well-known sequential rotation arrays. Microstrip patch arrays with such single-feed dual-CP dual-beam functionalities can be synthesized through a straightforward analytical approach that accurately predicts the radiation patterns for both right- and left-handed CP beams. The proposed technique and design methodology were verified by two proof-of-concept microstrip arrays consisting of 8×8 linearly polarized circular patch elements operating in the K-band, one with uniform excitation amplitudes and the other with tapered excitations for sidelobe suppression. Both arrays were fabricated and measured, experimentally achieving a joint S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> <; -10 dB, axial ratio <; 3 dB, and 3 dB gain bandwidth of more than 22.5%/20.0% and 16.7%/15.8%, respectively, for the right-and left-handed CP beams. Within this broad operational band, the beam squinting is on average within ±3°. The proposed dual-CP dual-beam arrays have fully planarized structures, low profiles, wide operational bandwidths, and high polarization purity, making them useful candidates for applications including satellite communications, point-to-multipoint communications, and so on.

Flexible Dual-Band Dual-Beam Radiation of Reflector Antennas by Embedding Resonant Phase Alignment Elements for Power Refocusing

This article presents a dual-band composite reflector antenna by embedding an array of metallic phase alignment elements (PAEs) on a selected area of reflector. As a result, this phase-configurable reflector may radiate two relatively arbitrary beams at two widely separated frequency bands, respectively. In this concept, a conventional parabolic surface is first created for ordinary field radiation by a focal feed in the low-frequency band. Afterward, a feed of high-frequency band is offset from the focal point to result in defocused radiation due to the phase distortion of reflection from the parabolic reflector. Metallic PAEs are subsequently implemented on the reflector to configure their phases of reflections for distortion compensation, and thus to refocus the radiation power along a desired direction. Here, the resonance of PAEs also specifies a valid high-frequency range. In this article, the methodology is first presented with radiation discrepancy evaluated to validate the design concept, which is further validated by full-wave simulations. Numerical examples are presented to demonstrate the feasibility.

Metasurface-Enabled Antiparallel Dual-Beam Rectangular-Waveguide Antenna

We propose a metasurface (MTS) structure integrated at the aperture of a flanged rectangular waveguide to produce dual-beam radiation. The dual beams are antiparallel in an orientation and perpendicular to the boresight direction. The MTS is backed by a dielectric slab to produce a substrate integrated waveguide-like response above the flange. The MTS is engineered to limit the boresight emission from the waveguide aperture, as well as to allow symmetric wave splitting between the MTS and waveguide flange. A lens-like end texturing involving surface tapering and electromagnetic bandgap cells is utilized to enhance the beam directivity at endfire from the flange. The dual-beam radiation exists for all frequencies between 10.5 and 12.4 GHz. The proposed design is modeled via full-wave simulation in commercial software, then validated through the measurement of a fabricated prototype.

Dual-Beam Periodic Leaky-Wave Antenna With Reduced Beam Squinting

In this letter, a dual-beam periodic leaky-wave antenna with a low beam-squinting character is presented. It has a simple and low-profile configuration, which consists of 15 slot radiating elements and one microstrip feedline. The slot radiating element creates nulls in the pattern at forward and backward endfire. By properly arranging the radiating elements with a small separation, the higher order spatial harmonics are suppressed. Fed by an air-substrate microstrip line working on the non-dispersion transverse electromagnetic (TEM) mode, the antenna has a moderate phase constant leading to a stable endfire array factor. By integrating the almost unchanged array factor and element pattern, the dual-beam radiation pattern with reduced beam squinting is obtained. To verify the design strategy, a prototype was designed, fabricated, and measured. Over the operating bandwidth from 2.7 to 3.2 GHz, the antenna exhibits a small measured beam squint of 6.8°.