Showing papers on "Dipole antenna published in 2019"
TL;DR: In this article, a dual-band dual-polarized base station antenna array is developed for 5G applications by introducing a frequency-selective surface (FSS) between radiators operating in the 0.69-0.96 GHz and 3.5-4.9 GHz bands.
Abstract: A dual-band dual-polarized base station antenna array is developed for fifth generation (5G) applications. Low-profile characteristic, high isolations, and shared-aperture are realized by introducing a frequency-selective surface (FSS) between radiators operating in the 0.69–0.96 GHz (B1) and 3.5–4.9 GHz (B2) bands. The dual-polarized B1-band antenna has a low-profile height of $0.12~\lambda _{L}$ ( $\lambda _{L}$ is the wavelength at the center frequency of B1). As for the B2 band, a $2 \times 2$ dual-polarized array sharing the same aperture with the B1-band antenna is developed for the sub-6 GHz band. Severe mutual coupling between B1- and B2-band antennas is reduced by the FSS. High port isolation (> 25 dB) between B1- and B2-band antennas is achieved. A prototype consisting of one B1-band antenna and a $2 \times 2$ B2-band antenna array is fabricated. Measured results show that the proposed dual-band dual-polarized array achieves 32.7% and 33.3% bandwidth in the B1 and B2 bands, respectively. Measured results also demonstrate that the proposed array offers stable radiation patterns, high gains, and high cross-polarization discriminations (XPD > 20 dB) across the two frequency bands. These attractive features make this array an ideal candidate for future 5G massive MIMO base station antenna developments.
137 citations
27 Aug 2019
TL;DR: AiP technology has emerged as the mainstream antenna and packaging technology for various mmWave applications, and some recommendations on research topics are presented to further the state of the art of AiP technology.
Abstract: Antenna-in-package (AiP) technology, in which there is an antenna (or antennas) with a transceiver die (or dies) in a standard surface-mounted device, represents an important antenna and packaging technology achievement in recent years. AiP technology has been widely adopted by chipmakers for 60-GHz radios and gesture radars. It has also found applications in 77-GHz automotive radars, 94-GHz phased arrays, 122-GHz imaging sensors, and 300-GHz wireless links. It is believed that AiP technology will also provide elegant antenna and packaging solutions to the fifth generation and beyond operating in the lower millimeter-wave (mmWave) bands. Thus, one can conclude that AiP technology has emerged as the mainstream antenna and packaging technology for various mmWave applications. This article will provide an overview of the development of AiP technology. It will consider antennas, packages, and interconnects for AiP technology. It will show that the antenna choice is usually based on those popular antennas that can be easily designed for the application, that the package choice is governed for automatic assembly, and that the materials and processes choices involve tradeoffs among constraints, such as electrical performance, thermal–mechanical reliability, compactness, manufacturability, and cost. This article also shows a probe-based setup to measure mmWave AiP impedance and radiation characteristics. It goes on to give AiP examples implemented, respectively, in a low-temperature co-fired ceramic, an embedded wafer level ball grid array process, and a high-density interconnect processes. Finally, this article will summarize and present some recommendations on research topics to further the state of the art of AiP technology.
124 citations
TL;DR: In this article, a 3D-printed Luneburg lens with a simplified geometry is presented, where rod-type structures are employed as the unit cell of the gradient-index material to realize the required permittivity distribution in the lens.
Abstract: A 3-D-printed Luneburg lens with a novel simplified geometry is presented. The rod-type structures are employed as the unit cell of the gradient-index material to realize the required permittivity distribution in the lens. A prototype designed in the Ka -band is manufactured successfully by using a commercial 3-D printing facility. The substrate-integrated waveguide fed magnetoelectric (ME)-dipole antenna with endfire radiation is introduced as the feed for the Luneburg lens due to its wideband performance and compact configuration. By combining the lens with a set of the ME-dipoles, a millimeter-wave (mm-wave) multibeam Luneburg lens antenna is designed, fabricated, and measured. An overlapped impedance bandwidth of wider than 40% that can cover the entire Ka -band and mutual coupling below −17 dB are verified by the fabricated prototype. Nine stable radiation beams with a scanning range between ±61°, gain up to 21.2 dBi with a variation of 2.6 dB, and radiation efficiency of around 75% are achieved as well. With the advantages of good operating features, low fabrication costs, and ease of integration, the proposed multibeam Luneburg lens antenna would be a promising candidate for the fifth-generation (5G) mm-wave multiple-input multiple-output (MIMO) applications in 28 and 38 GHz bands.
115 citations
TL;DR: In this article, a planar array antenna with omnidirectional radiation in horizontal plane is proposed for the 26 GHz fifth-generation (5G) broadcast applications, which is composed of two dipoles and a substrate integrated cavity (SIC) as the power splitter.
Abstract: In this paper, a compact, broadband, planar array antenna with omnidirectional radiation in horizontal plane is proposed for the 26 GHz fifth-generation (5G) broadcast applications. The antenna element is composed of two dipoles and a substrate integrated cavity (SIC) as the power splitter. The two dipoles are placed side-by-side at both sides of the SIC, and they are compensated with each other to form an omnidirectional pattern in horizontal plane. By properly combing the resonant frequencies of the dipoles and the SIC, a wide impedance bandwidth from 24 to 29.5 GHz is achieved. To realize a large array while reducing the complexity, loss, and size of the feeding network, a novel dual-port structure combined with radiation and power splitting functions is proposed for the first time. The amplitude and phase on each element of the array can be tuned, and therefore, the grating lobes level can be significantly reduced. Based on the dual-port structure, an eight-element array with an enhanced gain of over 12 dBi is designed and prototyped. The proposed antenna also features low profile, low weight, and low cost, which is desirable for 5G commercial applications. Measured results agree well with the simulations, showing that the proposed high-gain array antenna has a broad bandwidth, omnidirectional pattern in horizontal plane, and low side-lobes.
97 citations
TL;DR: A novel technique for surrogate modeling of antenna structures is proposed that involves a construction of two levels of surrogates, both realized as kriging interpolation models and allows uniform allocation of training data samples in a straightforward manner.
Abstract: Utilization of electromagnetic (EM) simulation tools is mandatory in the design of contemporary antenna structures. At the same time, conducting design procedures that require multiple evaluations of the antenna at hand, such as parametric optimization or yield-driven design, is hindered due to the high cost of accurate EM analysis. To a certain extent, this issue can be addressed using fast replacement models (also referred to as surrogates). Unfortunately, due to curse of dimensionality, traditional data-driven surrogate modeling methods are limited to antenna structures described by a few parameters with relatively narrow parameter ranges. This is by no means sufficient given the complexity of modern designs. In this paper, a novel technique for surrogate modeling of antenna structures is proposed. It involves a construction of two levels of surrogates, both realized as kriging interpolation models. The first model is based on a set of reference designs optimized for selected performance figures. It is used to establish a domain for the final (second level) surrogate. This formulation permits efficient modeling within wide ranges of antenna geometry parameters and wide ranges of performance figures (e.g., operating frequencies). At the same time, it allows uniform allocation of training data samples in a straightforward manner. Our approach is demonstrated using two microstrip antenna examples and is compared with conventional kriging and radial basis function modeling. Application examples for antenna optimization are also provided along with experimental validation.
93 citations
TL;DR: In this article, a dual-polarized magneto-electric (ME)-dipole antenna with a bandpass filtering response is proposed, which consists of four shorted patches, in which the magnetic dipole mode is formed by the slot-aperture between patches.
Abstract: This paper presents a novel low-profile dual-polarized magneto-electric (ME)-dipole antenna with a bandpass filtering response. The proposed ME-dipole antenna consists of four shorted patches, in which the magnetic dipole mode is formed by the slot-aperture between patches. Therefore, the height of the antenna is not limited to $0.25\lambda _{c}$ , but can be as low as $0.11\lambda _{c}$ . By symmetrically inserting four slots on the patches, a wide impedance bandwidth is obtained, and a controllable radiation null is generated at the upper band-edge to enhance the out-of-band suppression level. On the other hand, by properly designing the length of the feeding lines, another controllable radiation null and its second harmonic null are generated on each side of the passband, improving the selectivity and the suppression level of both the lower and upper stopbands without degrading the in-band performance. The measured results show that the prototype has a −15 dB impedance bandwidth of 27.6%, covering the specific 5G NR band n65 (3.3–4.2 GHz). In addition, the in-band average gain is 8.2 dBi and the out-of-band suppression level is more than 20 dB.
85 citations
TL;DR: In this paper, a stacked antenna array consisting of a lowerband antenna element working in 690-960 MHz frequency band and four upper-band antenna elements operating in the 3.5-4.9 GHz band is designed to demonstrate the concept.
Abstract: A novel stacked antenna configuration is proposed for the designs of shared-aperture base station antennas. An antenna array consisting of a lower-band antenna element working in 690–960 MHz frequency band and four upper-band antenna elements operating in the 3.5–4.9 GHz band is designed to demonstrate the concept. In the proposed configuration, four upper-band antenna elements are placed over the aperture of the lower-band antenna. Four metallic sheets are introduced to provide capacitive loading for the lower-band antenna and simultaneously offer a ground plane for the upper-band antennas. Therefore, low-profile characteristic and high isolations between the dual-band antennas are guaranteed. The overall height of the antenna array is only $0.17\lambda _{\text {L0}}$ ( $\lambda _{\text {L0}}$ is the free-space wavelength at the center frequency of the lower band), which is much lower than those of conventional designs. The measured results demonstrate that the designed antenna array achieves 32.7% and 33.3% impedance bandwidth in the lower and upper bands, respectively. High port isolations (>30 dB), high gains (>8 dBi), and stable radiation patterns are achieved in the two frequency bands. Owing to its simple structure and compact size, the resultant antenna array is easy for fabrication and is a promising candidate for sub-6 GHz band and 690–960 MHz band antennas.
81 citations
TL;DR: In this article, the authors present concepts for antennas that generate electromagnetic signals from mechanical motion, which can theoretically exceed the performance of conventional short dipole and coil transmitters by more than eight orders of magnitude for frequencies of 1 kHz and below.
Abstract: Antennas that operate in the very low frequency (LF) band and below are useful for a number of applications, including long-distance and underwater communication. When constrained in size, the antennas are electrically small and very inefficient. This has motivated the need for novel approaches to LF antenna design. Here, we present concepts for antennas that generate electromagnetic signals from mechanical motion. We first review the generated fields and efficiency of conventional magnetic and electric dipole transmitters. This is then extended to their mechanical counterparts for comparison. Our results show that the motion of magnets or electrets (the electrical analog of a magnet) can efficiently radiate electromagnetic energy when coupled to a low-loss electromechanical suspension. Mechanical antennas, with spatial dimensions on the order of a meter, can theoretically exceed the performance of conventional short dipole and coil transmitters by more than eight orders of magnitude for frequencies of 1 kHz and below. This paper is intended to lay the foundation for future development involving the implementation of efficient, small form-factor, mechanically actuated antennas.
79 citations
TL;DR: Meta-surface superstrates are used to decouple two linear polarized antennas coupled in H-plane and E-plane, respectively by properly designing the geometry of the double layer short wires as the unit cell of the meta-surface, as well as the height of theMeta-superstrate.
Abstract: In this paper, meta-surface superstrates are used to decouple two linear polarized antennas coupled in H-plane and E-plane, respectively. By properly designing the geometry of the double layer short wires as the unit cell of the meta-surface, as well as the height of the meta-superstrate, two linearly polarized antennas can be decoupled in H-plane and E-plane, respectively. Both the antenna pairs coupled in E- and H-planes with and without meta-surfaces are fabricated and measured. The results demonstrate that the antennas with the meta-surface superstrate are able to operate in the band of 3.3–3.7 GHz with reflection better than −15 dB and the isolation can be improved from 10 to 25 dB in the H-plane case and can be improved from 15 to 30 dB in the E-plane case. Such decoupling method can be applied extensively in 5G base stations where size constraints are becoming stringent.
75 citations
TL;DR: In this article, a compact quasi-isotropic dielectric resonator antenna (DRA) with filtering response is investigated in a communication. But the authors only evaluated the performance of the DRA at 2.4 GHz.
Abstract: A compact quasi-isotropic dielectric resonator (DR) antenna (DRA) with filtering response is first investigated in this communication. The cylindrical DRA is fed by a microstrip-coupled slot, exciting in its ${\text {HEM}}_{11 \delta }$ mode which radiates like a magnetic dipole. A small ground plane is used for this DRA and it radiates like an electric dipole. The combination of the two orthogonal dipoles leads to a quasi-isotropic radiation pattern, with gain deviation as low as 5.8 dB in the 360° full space. To integrate the filtering function, the microstrip feed-line and the ground plane are turned upside down, and further two stubs with different lengths are used together to excite the DR. Due to the different loading effects of the feeding stubs, two resonances of the DR ${\text {HEM}}_{11 \delta }$ mode are excited in the passband, effectively enhancing the bandwidth of DRA ( $\varepsilon _{r} = 20$ ) to 7%. Furthermore, two controllable radiation nulls are generated by the DR loaded microstrip feed-line, bringing about high frequency selectivity at the edges of the passband and a quasi-elliptic bandpass response. For demonstration, a prototype operating at 2.4 GHz was fabricated and tested; reasonable agreement is obtained between the simulated and measured results.
72 citations
TL;DR: In this article, two 24 GHz horizontally polarized $1 \times 8$ patch antenna arrays were developed for automotive radar applications, which offer the advantages of wide fan beams and high gain.
Abstract: In this paper, two 24 GHz horizontally polarized $1 \times 8$ patch antenna arrays were developed for automotive radar applications. The proposed antenna arrays offer the advantages of wide fan beams and high gain. The far-field radiation patterns are widened in the E-plane by disturbing the near-field distribution of each driven patch. In Design I, the driven patch is loaded with a parasitic loop, which functions as a director in the E-plane. Due to the directing effect, the E-plane beamwidth can be increased. The experimental verification prepared for Design I showed that a beamwidth of 130° and a gain of 12.2 dBi can be achieved through this method. To further enhance the beamwidth, another array with each patch loaded with parasitic mushroom-like elements was proposed by Design II. The PMLEs are 180° out of phase to their corresponding driven patch. The cancelation effects can be properly managed to slightly sacrifice the gain of the array in return for a wider beamwidth in the E-plane. Design II exhibits a wider beamwidth of 150° and a lower gain of 11.1 dBi.
TL;DR: In this article, a dual-polarized frequency-reconfigurable low profile antenna with harmonic suppression for 5G application is presented, which consists of a pair of ±45° polarized frequency reconfigurable dipole antennas, two vertically placed feeding structures with filtering branches, and an artificial magnetic conductor (AMC) surface.
Abstract: A dual-polarized frequency-reconfigurable low-profile antenna with harmonic suppression for 5G application is presented in this letter. The proposed design consists of a pair of ±45° polarized frequency-reconfigurable dipole antennas, two vertically placed feeding structures with filtering branches, and an artificial magnetic conductor (AMC) surface. By introducing the U-shaped structure, a better impedance matching performance is achieved in two bands. Measured results show that the proposed antenna can operate at 3.24–4.03 and 4.44–5.77 GHz by controlling the on–off of PIN diodes, and port isolation of two bands is greater than 25 dB. What is more, two-octave harmonic suppression is realized by loading the filtering branches. In order to obtain stable unidirectional radiation pattern in the operating bands and low-profile characteristic, a dual-band 4 × 4 AMC reflector is fabricated. Finally, a maximum gain of 6.86 dBi in low frequency band and 8.14 dBi in high frequency band are obtained. Besides, the height of the proposed antenna is 0.1 λ at 3.3 GHz. Experimental results show that the antenna can meet the needs of the 5G communication.
TL;DR: Investigations show that the antenna designed with an inverse S-shape patch and connecting rectangular box in the microstrip line has a higher efficiency and gain compare to the conventional meander shape antenna, and the gain and efficiency can be improved through adjusting the rectangular box with applying parasitic element and the shaped ground.
Abstract: Internet of Things (IoT) based application requires integration with the wireless communication technology to make the application data readily available. In this paper, a modified meander shape microstrip patch antenna has been proposed for IoT applications at 2.4 GHz ISM (Industrial, Scientific and Medical) band. The dimension of the antenna is 40×10×1.6 mm
3
. The antenna design is comprised of an inverse S-shape meander line connected with a slotted rectangular box. A capacitive load (C-load) and parasitic patch with the shaped ground are applied to the design. Investigations show that the antenna designed with an inverse S-shape patch and connecting rectangular box in the microstrip line has a higher efficiency and gain compare to the conventional meander shape antenna. The C-load is applied to the feed line to match the impedance. Moreover, parametric studies are carried out to investigate the flexibility of the antenna. Results show that, the gain and efficiency can be improved through adjusting the rectangular box with applying parasitic element and the shaped ground. The parasitic element has high impact on the bandwidth of the antenna of 12.5%. The finalized antenna has a peak gain of -0.256 dBi (measured) and 1.347 dBi (Simulated) with 79% radiation efficiency at 2.4 GHz. To prove the efficiency and eligibility in IoT applications, the measurement of the power delivered and received by the antenna at 2.4 GHz is performed and compared with the results of a dipole antenna. The antenna is integrated with 2.4 GHz radio frequency module and IoT sensors to validate the performance. The antenna novelty relies on the size compactness with high fractional bandwidth that is validated through the IoT application environment.
TL;DR: In this paper, the authors proposed a dual-band shared-aperture beam-scanning antenna array based on the concept of structure reuse, which consists of four Ku-band linear antenna arrays implemented by the substrate-integrated waveguide (SIW) and four Ka-band antenna arrays.
Abstract: This paper describes the design and realization of a Ku/Ka dual-band shared-aperture beam-scanning antenna array based on the concept of structure reuse. The antenna consists of four Ku-band linear antenna arrays implemented by the substrate-integrated waveguide (SIW) and four Ka-band linear antenna arrays. To increase the aperture utilization efficiency, the Ku-band antenna is employed as some sidewalls of the Ka-band antenna. Thanks to this compact topology, the element spacing at two frequency bands is able to meet the requirement of a wide-angle beam scan. Both feeding networks of these two arrays are designed by proper SIW power dividers through the printed circuit board fabrication process. In addition, the self-filtering characteristic of the antenna, the orthogonal polarization, and the optimal layout of the array are employed to ensure the high channel isolation between the two antennas operating at different frequency bands over the whole beam scan range. The isolation between antennas is better than 28 and 70 dB at the Ku-band and Ka-band, respectively, scanning up to even 40°. The proposed shared-aperture concept and the design results have been validated by the experimental results.
TL;DR: A novel quasi-Yagi antenna is proposed for millimeter-wave (mmWave) 5G cellular handsets operating in the 28 GHz band and designed to be compact through modification of the planar folded dipole topology so that it can be mounted inside a compact mobile terminal.
Abstract: A novel quasi-Yagi antenna is proposed for millimeter-wave (mmWave) 5G cellular handsets operating in the 28 GHz band. The proposed antenna is designed to be compact through modification of the planar folded dipole topology so that it can be mounted inside a compact mobile terminal. A vertically stacked structure utilizing a multilayer printed circuit board (PCB) and via holes is applied to the antenna topology to minimize the antenna lateral width while maintaining the characteristics of the planar folded dipole antenna. A single antenna yields a $-$ 10 dB bandwidth for a return loss of 12.3% (26.3 to 29.75 GHz) and a gain of 5.51 dBi at 28 GHz. The change in beam patterns due to the chassis effect when four-element linear arrays are inserted into the upper and side edge inside the terminal is analyzed.
TL;DR: In this paper, a dual-mode compressed dipole resonating at high-order modes is proposed to enhance bandwidth and directivity by loading the two dipole arms with two stubs.
Abstract: A dual-mode compressed dipole resonating at high-order modes is proposed to enhance bandwidth and directivity by loading the two dipole arms with two stubs. Characteristic mode analysis shows that with by introducing the loading stubs, the fifth-order mode of the proposed dipole shifts close to its third-order mode for achieving a wideband operation with enhanced gain. A prototype is designed to validate the principle and design approach experimentally. These measurements show that the gain of the proposed compressed dipole is 4 dBi, higher than that of a conventional dipole over the desired operating band of 3.3–3.6 GHz for the coming 5G applications.
TL;DR: Simulations prove that the antenna array can cover the angle of over 180° with high gain over the frequency range from 26 to 40 GHz and has large coverage over the whole bandwidth and peak gain of 8 dBi at 28 and 38 GHz.
Abstract: The goal of this paper is to propose a new antenna array architecture that aims to solve the most known limitations of phased antenna arrays, resulting a good candidate for next 5G mobile handsets. The architecture consists of five quasi-Yagi antennas printed on the short edge of a Roger RO3003 substrate, pointing in different directions, and a switch to feed each antenna and steer the beam. Simulations prove that the antenna array can cover the angle of over 180° with high gain over the frequency range from 26 to 40 GHz. Alternative designs to make the structure more compact further demonstrate the validity of the concept. The optimized corner array of four elements is fabricated and passive and active measurements are performed with the Microwave Vision Group (MVG) Starlab 50 GHz. The results of the passive measurements are in accordance with the simulations and show that the proposed quasi-Yagi antenna array has large coverage over the whole bandwidth and peak gain of 8 dBi at 28 and 38 GHz. The active measurements of the array connected to the front end module (FEM) and integrated in the phone case further confirm the radiation properties of the switchable antenna array at 28 GHz in a quasi-real scenario.
TL;DR: In this paper, a wideband multiple-microstrip dipole antenna with dual polarization was proposed, which consists of a radiator, a cross-shaped slot coupler, a pair of microstrip baluns, and a reflector.
Abstract: A wideband multiple-microstrip dipole antenna with dual polarization is proposed in this letter. The antenna consists of a radiator, a cross-shaped slot coupler, a pair of microstrip baluns, and a reflector. When baluns are excited, the cross-shaped slot coupler would work as a four-way equal-split power divider and generate four differential signals at four ends of the slotlines. Afterward, the signals would be coupled to four modified dipoles to radiate and synthesize slant ±45° linear polarizations. The proposed design is verified by the fabrication and testing of a prototype antenna. Measured results agree well with the simulated ones, giving a wide impedance bandwidth from 1.68 to 2.75 GHz, a high port-to-port isolation (better than 37 dB) within the operating frequency bandwidth, and a good radiation pattern. Besides, the proposed antenna maintains a compact structure measuring 0.78 λ 0 × 0.78 λ 0 × 0.18 λ 0.
TL;DR: In this paper, a dual-polarized antenna with total dimensions of 31 × 31 × 14mm3 is proposed for the fifth-generation base stations at 3.5 GHz. But, the proposed antenna operates in the range of 3.2-3.9 GHz with S11 ≤−15 dB and has port isolation better than 40 dB.
Abstract: A compact dual-polarized antenna with total dimensions of 31 × 31 × 14 mm3 is proposed for the fifth-generation base stations at 3.5 GHz. The antenna consists of two orthogonal bow-tie dipoles. The bandwidth is enhanced using eight parasitic strips along with the dipole patches, two U-shaped slots around the feeding positions, and dielectric cavity, which brings two resonant frequencies closer to each other. The isolation between the dual polarization is improved by adding two shorting pins symmetrically with respect to the feeding cable. The proposed antenna operates in the range of 3.2–3.9 GHz with S11 ≤−15 dB and has port isolation better than 40 dB. The measured results show good performances in front-to-back ratio, cross-polarization discrimination ratio, and stable radiation patterns. Finally, the proposed antenna is used to construct a 2 × 4 multiple-input–multiple-output (MIMO) antenna with a compact size of 101 × 170 × 14 mm3 (1.16 λ 0 × 1.96 λ 0 × 0.16 λ 0). The MIMO antenna is fabricated and tested. Good results are observed.
TL;DR: In this article, a theoretical model is developed to capture the impacts of the change of soil moisture on the return loss, resonant frequency, and bandwidth of a buried dipole antenna.
Abstract: The realization of Internet of underground things (IOUT) relies on the establishment of reliable communication links, where the antenna becomes a major design component due to the significant impacts of soil. In this paper, a theoretical model is developed to capture the impacts of the change of soil moisture on the return loss, resonant frequency, and bandwidth (BW) of a buried dipole antenna. Experiments are conducted in silty clay loam, sandy, and silt loam soil, to characterize the effects of soil, in an indoor testbed and field testbeds. It is shown that at subsurface burial depths (0.1–0.4 m), the change in soil moisture impacts communication by resulting in a shift in the resonant frequency of the antenna. Simulations are done to validate the theoretical and measured results. This model allows system engineers to predict the underground antenna resonance and also helps to design an efficient communication system in IOUT. Accordingly, a wideband planar antenna is designed for an agricultural IOUT application. Empirical evaluations show that an antenna designed considering both the dispersion of soil and the reflection from the soil–air interface can improve communication distances by up to five times compared to antennas that are designed based on only the wavelength change in soil.
TL;DR: In this paper, an ultra-wideband and wide-scanning tightly coupled dipole array with low profile height and lightweight is presented, where a novel split ring (SR) printed on planar single-layer printed circuit board is designed and loaded on each element of the proposed array to replace the conventional wide-angle impedance matching superstrates, which usually consist of dielectric slabs.
Abstract: An ultra-wideband and wide-scanning tightly coupled dipole array with low-profile height and lightweight is presented. A novel split ring (SR) printed on planar single-layer printed circuit board is designed and loaded on each element of the proposed array to replace the conventional wide-angle impedance matching (WAIM) superstrates, which usually consist of dielectric slabs. Consequently, the array achieves a 7.2:1 impedance bandwidth (0.3–2.15 GHz) while scanning up to 70° in the E-plane and 45° in the H-plane for active VSWR $8 \times 8$ prototype array weighing only 4.3 kg (including an aluminum ground plane of 2.3 kg) was fabricated. The measured results are in good agreement with the simulated results.
TL;DR: In this article, a differential mode/common mode (DM/CM) design was proposed to achieve a highly integrated multi-input multi-output (MIMO) antenna unit in mobile terminals.
Abstract: A novel concept of antenna design, termed differential mode/common mode (DM/CM) design, is proposed to achieve a highly integrated multi-input multi-output (MIMO) antenna unit in mobile terminals. The inspiration comes from a dipole fed by a differential line which can be considered a DM feed. What will happen if the DM feed is transformed into a CM feed? Some interesting features are provided in this article. By symmetrically placing one DM antenna and one CM antenna together, a DM/CM antenna can be achieved. Benefitting from the coupling cancellation of antiphase currents and the different distributions of the radiation currents, a DM/CM antenna can obtain high isolation and complementary patterns, even if the radiators of the DM and CM antennas are overlapped. Therefore, good MIMO performance can be realized in a very compact volume. To validate the concept, a miniaturized DM/CM antenna unit is designed for mobile phones. The 24.2 dB isolation and complementary patterns are achieved in the dimension of $0.330 \lambda _{0} \times 0.058\lambda _{0} \times 0.019 \lambda _{0}$ at 3.5 GHz. One $8 \times 8$ MIMO antenna array is constructed by using four DM/CM antenna units and shows good overall performance. The proposed concept of DM/CM design may also be promising for other applications that need high isolation between closely packed antenna elements and wide-angle pattern coverage.
TL;DR: In this article, an improved magnetoelectric (ME) dipole with a defected ground structure is proposed, which is excited by a planar L-probe.
Abstract: A broadband endfire antenna array is investigated for 5G millimeter-wave applications. First, an improved magnetoelectric (ME) dipole with a defected ground structure is proposed, which is excited by a planar L-probe. This proposed ME-dipole antenna shows stable radiation during the relative bandwidth of 53.0%. Next, a 16-way substrate-integrated coaxial line (SICL) feeding network is presented. Its bandwidth is 109.5% for ${|S_{11}|}\leq -15 \; \mathrm {dB}$ and insertion loss is less than 13.4 dB. This full-corporate SICL feeding scheme is utilized to construct the broadband antenna array. Finally, the proposed antenna array is fabricated and its performance is evaluated. Considering the impedance bandwidth for $|S_{11}| \leq -10 \; \mathrm {dB}$ , the 3 dB gain bandwidth, and the radiation efficiency, the overall measured operating bandwidth is 50.7%, which covers two main candidate frequency bands of 28 and 39 GHz. The cross-polarization level is less than −19.0 dB and the front-to-back ratio is better than 20.0 dB in the whole operating bandwidth. Additionally, a $4\times 4\,\,2$ -D multibeam array is also simulated to verify the beamforming potential of the proposed antenna array.
TL;DR: In this article, a bidirectional same sense circularly polarized (Bi-SSCP) endfire antenna array with reconfigurable polarization is proposed and implemented by adopting two pairs of switchable electric dipoles, which have a 180° phase difference inherently.
Abstract: In this communication, a bidirectional same sense circularly polarized (Bi-SSCP) endfire antenna array with reconfigurable polarization is proposed and implemented. First, a circular polarization (CP) reconfigurable endfire antenna element is realized by adopting two pairs of switchable electric dipoles, which have a 180° phase difference inherently. Along with the fixed magnetic dipole, the endfire antenna element can work at two CP states, i.e., left-hand CP (LHCP) and right-hand CP (RHCP) by switching the states of the two electric dipoles. Then, a Bi-SSCP endfire antenna array with polarization diversity is developed by using two identical endfire antenna elements placed back-to-back with a single feeding probe. For verification, prototypes of the designed endfire antenna element and Bi-SSCP endfire antenna array are fabricated and measured. The measured results show reasonable agreement with the simulated ones. The measured overlapped bandwidth for 10 dB return loss and 3 dB axial ratio of the Bi-SSCP endfire antenna array is from 5.7 to 5.9 GHz for the two CP states.
TL;DR: This work addresses the design and implementation of a broadband differential rectifier (DR) combined with an Archimedean spiral dipole antenna (ASDA) for wireless power harvesting at low incident power densities below 200 μW/cm2 and exhibits an improved RF-DC conversion efficiency over a wide frequency range from 1.2 to 5 GHz.
Abstract: This work addresses the design and implementation of a broadband differential rectifier (DR) combined with an Archimedean spiral dipole antenna (ASDA) for wireless power harvesting at low incident power densities below 200 μ W/cm 2 . The proposed design exhibits an improved RF-DC conversion efficiency over a wide frequency range from 1.2 to 5 GHz. This frequency band is associated with several wireless communication services, for instance, ISM, WLAN, 5G, LTE, and GPS applications. The receiving planar ASDA exhibits circular polarization and has an average measured gain of 4.5 dBi from 1.2 to 5 GHz. To enable a wide operating bandwidth, the rectifier circuit is constituted by two architectures, designated A and B. Each scheme is designed to harvest power efficiently across a specific bandwidth. The optimal performance of both rectifiers are obtained using the nonlinear harmonic-balance simulations. The antenna–rectifier integration yields a compact rectenna with a high-efficiency performance over the intended bandwidth from 1.2 to 5 GHz for an input power of 9 dBm and terminal load resistance of 1 k Ω . The total measured RF-DC conversion efficiency is maintained above 30% across the entire frequency range with a peak value of 61% achieved at 1.2 GHz. In comparison with similar architectures, the proposed rectenna maintains a stable output efficiency despite the wide fluctuations in the input frequency and also has a minimum footprint size (58 × 55 mm 2 ).
TL;DR: In this article, a differentially fed dual-polarized planar antenna with a wide bandwidth and high common-mode suppression is presented, where two integrated baluns are utilized to excite the folded dipoles simultaneously to realize ±45° linear polarizations.
Abstract: A differentially fed dual-polarized planar antenna with a wide bandwidth and high common-mode (CM) suppression is presented in this paper. The antenna is composed of four folded dipoles that are connected to each other via the coplanar striplines. Two integrated baluns are utilized to excite the folded dipoles simultaneously to realize ±45° linear polarizations. Owing to the loaded shorting stubs, the impedance matching is improved and the operational bandwidth is broadened. Under differential-mode (DM) excitation, the antenna has a superior unidirectional radiation over a wide bandwidth. Under CM excitation, the antenna achieves a high level of CM suppression performance due to the proposed feeding structure. Measured results exhibit that the antenna gains a wide −15 dB differential impedance bandwidth of 51.1% (1.66–2.80 GHz) and a high port isolation of 38 dB between the differential ports. Moreover, the CM reflection coefficient is larger than −1.32 dB within the DM passband, which indicates that the high CM suppression is attained. To further validate the design concept, a $1\times4$ antenna array is fabricated and measured to demonstrate the superior performances of wide bandwidth, high port isolation, high CM rejection, and good unidirectional radiation.
TL;DR: It is predicted that one may construct large local density of states (LDOS) enhancements exceeding those given by a single antenna, which are ‘chiral’ in the sense of correlating with the unidirectional injection of fluorescence into the cavity.
Abstract: We analyse the resonant mode structure and local density of states in high-Q hybrid plasmonic-photonic resonators composed of dielectric microdisks hybridized with pairs of plasmon antennas that are systematically swept in position through the cavity mode. On the one hand, this system is a classical realization of the cooperative resonant dipole–dipole interaction through a cavity mode, as is evident through predicted and measured resonance linewidths and shifts. At the same time, our work introduces the notion of ‘phased array’ antenna physics into plasmonic-photonic resonators. We predict that one may construct large local density of states (LDOS) enhancements exceeding those given by a single antenna, which are ‘chiral’ in the sense of correlating with the unidirectional injection of fluorescence into the cavity. We report an experiment probing the resonances of silicon nitride microdisks decorated with aluminium antenna dimers. Measurements directly confirm the predicted cooperative effects of the coupled dipole antennas as a function of the antenna spacing on the hybrid mode quality factors and resonance conditions.
TL;DR: In this paper, a compact co-horizontally polarized (HP) in-band full-duplex (IBFD) antenna with omnidirectional patterns was proposed.
Abstract: This letter presents a compact co-horizontally polarized (HP) in-band full-duplex (IBFD) antenna with omnidirectional patterns. The Tx antenna is a variant turnstile antenna with four 90° progressively phased T-shaped monopoles, whereas the Rx antenna is an in-phase loop antenna with four symmetrically excited dipoles. The polarizations and radiation patterns of both antennas are horizontally polarized and omnidirectional patterns in the azimuth plane. Nevertheless, a high measured isolation of more than 37 dB across the desired band is achieved with an orthogonal spatial phase diversity approach. To the best of our knowledge, this is the first time two co-HP omnidirectional antennas are integrated with a high isolation for the IBFD communication. The proposed antenna has the potential to double the spectral efficiency of wireless communication systems and to combat the polarization variations in the rich multipath environments.
TL;DR: In this article, a low mutual coupling array antenna operating in the Ku-band is proposed, where side metallic walls with a small resistive film are incorporated into both sides of the dipole antenna.
Abstract: A low mutual coupling array antenna operating in the Ku -band is proposed. To reduce mutual coupling, side metallic walls with a small resistive film are incorporated into both sides of the dipole antenna. These walls can also help impedance matching across the whole Ku -band. By investigating the current density distribution on the side wall with frequency, the appropriate positions of the resistive films are determined. Finally, the design is tested by measurement, which is in good agreement with simulation results. The performance is as follows: the operating bandwidth (OBW) is 11.9–20.3 GHz (52.2%) for the impedance bandwidth (IBW) with −10 dB and the low mutual coupling band with less than −20 dB. The radiation efficiency is over 63.9%. The active element gain is 1.88–4.57 dBi. The measured array gain is 15–16.7 dBi as scanning the beam from 0° to 45° at 16 GHz. The OBW is almost constant up to scan angle of 45°. The overall dimensions of the array structure with 17 elements are $1.2 \times 9.2 \times 0.44 \lambda _{\mathrm {low}}$ at the lowest operating frequency of 12 GHz.
TL;DR: In this article, a low-profile MIMO antenna is proposed for applications in mobile devices, which can work from 3.4 to 3.8 GHz with a profile of 0.97 mm.
Abstract: A low-profile MIMO antenna is proposed for applications in mobile devices. The antenna is designed by placing multiple inverted-F antennas (IFAs) on an artificial magnetic conductor (AMC) ground. The IFAs excite two distinct modes on the AMC, i.e., the local resonant mode and the TM0 surface-wave mode. By combining the two modes, a fractional bandwidth of 12% is realized with a profile of $0.01\lambda _{0}$ , where $\lambda _{0}$ is the free-space wavelength at the center frequency. Within the working band, the radiation efficiencies are higher than 50%, the mutual couplings among antennas lower than −10 dB, and envelope correlation coefficients (ECCs) lower than 0.2. To validate the antenna design, a MIMO antenna with eight elements is fabricated and measured. The antenna can work from 3.4 to 3.8 GHz. The total thickness of the antenna is only 0.97 mm, which can be integrated into smartphones as their back-covers without occupying the inner space of the device. The throughput achieved by the antenna in an outdoor environment is also tested using a fifth-generation (5G) MIMO system. The MIMO performance will be discussed and compared with traditional antennas.