Multiband Function Research Articles

Orthogonally dual‐polarised MIMO antenna array with pattern diversity for use in 5G smartphones

A new multiple-input/multiple-output (MIMO) antenna design is introduced for future smartphones. The proposed design contains four pairs of double-fed circular-ring resonators located at different edges of the smartphone printed circuit board (PCB) with an FR-4 substrate and a dimension of 75 × 150 mm2. The antenna elements are fed by 50-Ohm microstrip-lines and provide polarisation and radiation pattern diversity function due to the orthogonal placement of their feed lines. By inserting a rectangular slot under each microstrip feed-line, the mutual coupling characteristic of the antenna ports is reduced. A good frequency bandwidth (S11 ≤ − 10 dB) of 3.3–3.9 GHz has been obtained for the smartphone antenna array. Nevertheless, for S11 ≤ − 6 dB, this value is 3.1–4.3 GHz. More than 3 dB realised gain and 80% total efficiency are achieved for the single-element radiator. The design provides not only sufficient radiation coverage supporting different sides of the mainboard but also the polarisation diversity. In addition, sufficient properties are obtained in the vicinity of human-hand/human-head. The proposed MIMO antenna design is also capable to generate dual- or multi-band function. Moreover, a new and compact phased array millimeter-wave (mm-wave) antenna design with end-fire radiation beams is introduced which can be easily integrated into smartphones.

Compacted Conformal Implantable Antenna With Multitasking Capabilities for Ingestible Capsule Endoscope

This study presents a multi-band conformal antenna based endoscopic system for robust biotelemetry communications, which covers five important bands, including the MedRadio (401-406 MHz), Industrial, Scientific, and Medical (ISM) (433.1-434.8 MHz, 868-868.6 MHz, 902-928 MHz), and midfield (1200 MHz) bands. These bands are intended for functions such as biotelemetry, power saving, and wireless power transfer (WPT). The proposed antenna is printed on a flexible material Rogers ULTRALAM with a thickness of only 0.1 mm, which can be easily wrapped around the inner wall of a capsule. Owing to the insertion of the via and open-ended meandered slots in the radiator and in the ground plane, the footprints of the suggested antenna reduce considerably. In the flat form, the antenna is 57 mm 3 in volume, whereas in the wrapped form, it is only 48.98 mm 3 in volume. In a homogeneous muscle phantom, the proposed conformal antenna shows a 27.46% wider bandwidth at 402 MHz,whereas it shows a 13.2% and 5.42% bandwidth at 915 MHz and 1200 MHz, respectively. Furthermore, the specific absorption rate investigation at three resonance frequencies in various implanted locations shows compliance with the IEEE guidelines, thereby guaranteeing human safety. For measurements, a 3D capsule with batteries and circuitry is devised using a 3D printer, and the simulation results are experimentally validated in a box containing minced pork. Finally, the robustness of the communication link is confirmed through the link budget analysis at 1 Mb/s. The conformal design concept, omni-directional radiations, and multi-band functionality with a wider bandwidth in the MedRadio band of the suggested antenna will enhance the diversity of the capsule endoscope and be a good addition to the field of biotelemetry.

A WKB approach to the quantum multiband electron dynamics in the kinetic formalism

We derive a WKB-like asymptotic expansion of the multiband Wigner function. The model, derived in the envelope function theory, is designed to describe the dynamics in semiconductor devices when the interband conduction-valence transition cannot be neglected. We derive a hierarchy of equations that to lowest order consist of two HamiltonJacobi equations corresponding to the classical dynamics of point particles with positive and negative kinetic energy. Our methodology is based on the Van Vleck approach and a WKB-like asymptotic expansion procedure is used to reduce the numerical complexity of the Wigner multiband evolution system. An approximate closed-form solution is obtained by an iterative procedure that exploits the different time scales on which the intraband and interband dynamical variables evolve. The interband tunneling mechanism appearing to the first order of the expansion is expressed in a very simple mathematical form. By exploiting the highly oscillating behaviour of the multiband Wigner functions we derive a asymptotic expression of the interband transition probability. The resulting formulation reveals particularly close to the classical description of the particles motion and this formal analogy is useful to gain new physical insight and to profit of the numerical method developed for classical systems. The approximates evolution equations are used to simulate the evolution of the Wigner quasi-distribution function in a IRTD diode.

A dual feed PIN diode based switchable multiband planar meandered antenna for intelligent transportation system application

This article presents a dual feed switchable coplanar linearly polarized multiband meandered microstrip patch antenna. The antenna provides multiband functionalities with switching allowable at one of the nine adjacent frequencies. The proposed antenna, loaded with two symmetric PIN diodes, comprises dual-patch configuration and excited by coplanar microstrip feeds, it operates within 1 to 15 GHz frequency bands. The induced current of the antenna can be changed by switching the diodes, resulting in different operating frequency bands. The antenna has a nearly broadside radiation pattern and the impedance bandwidth is obtained up to 47% having a center frequency of 2.4 GHz for band range of 1 to 15 GHz. The measured gain of the antenna for 1.57, 2.4, 4.5, 4.71, 5.9, 6.53, 7.59, 10.8, and 11.87 GHz are 5, 5, 7, 6, 6.1, 4.4, 3.8, 3.5, and 1.87 dBi, respectively. The antenna has advantages of the simple biasing network, easy fabrication, and adjustment. It is suitable for many modern wireless communication systems like intelligent transportation system. This antenna is also useful in direct broadcast satellite applications.

Analysis and experimental verification of multi-band thin monopole antennas loaded with half-mode CRLH-inspired resonators

This paper presents analysis and experimental measurements of CPW and microstrip compact monopole antennas loaded with resonator circuits inspired from simplified half-mode composite right / left-handed unit cell. The antennas were designed to have a typical omnidirectional radiation pattern. The CPW fed dual-band antenna resonates at 2.4 and 5.8 GHz, respectively. The antenna size is 20 × 30 mm2 and the radiator patch is only 25% at 2.4 GHz and 60% 5.8 GHz in comparison with a conventional patch antenna. The microstrip triple-band antenna covers the frequency bands from 2 to 2.4 GHz, 5.4 to 6 GHz and 6.8 to 8 GHz. The antenna size is 28 × 25 mm2 which is less than 25% at lower frequency band compared to the size of the conventional patch antenna. Detailed theoretical and full-wave analysis is presented and experimental results demonstrate a good agreement between the measured and the simulated. The suggested antennas can be employed for compact size and multi-band functionalities in wireless applications. The loading technique can be adapted for more frequency bands.

The Mondrian Detection Algorithm for Sonar Imagery

A new algorithm called the Mondrian detector has been developed for object detection in high-frequency synthetic aperture sonar (SAS) imagery. If a second (low) frequency-band image is available, the algorithm can seamlessly exploit the additional information via an auxiliary prescreener test. This flexible single-band and multiband functionality fills an important capability gap. The algorithm’s overall prescreener component limits the number of potential alarms. The main module of the method then searches for areas that pass a subset of pixel-intensity tests. A new set of reliable classification features has also been developed in the process. The overall framework has been kept uncomplicated intentionally in order to facilitate performance estimation, to avoid requiring dedicated training data, and to permit delayed real-time detection at sea on an autonomous underwater vehicle. The promise of the new algorithm is demonstrated on six substantial data sets of real SAS imagery collected at various geographical sites that collectively exhibit a wide range of diverse seafloor characteristics. The results show that—as with Mondrian’s art—simplicity can be powerful.

Modified easy to fabricate E‐shaped compact patch antenna with wideband and multiband functionality

A flexible E-shaped patch antenna that is particularly easy to fabricate is presented. E-shaped patch antennas traditionally act as wideband microstrips. Here, first a novel folded L-shaped feed is used for improved wideband operation. Then, multiband operation is enabled through scaling and tight packing with low mutual coupling. The antenna equivalent circuit is presented, and the principles of operation at the two modes of the antenna are discussed. The traditional design undergoes a clever modification to allow it for particularly easy fabrication, which minimises the need for complex tools and enables a low budget manufacturing, and the methodology for this modification is presented. The fabricated prototype exhibits fractional bandwidth larger than 20% with extremely small total antenna dimensions 18 mm × 19 mm (about λ 0 /4 × λ 0 /4 at the centre frequency). The proposed design can be particularly useful in multiband array configurations through the demonstrated scaling and tight packing, as well as for wearable applications.

Peculiarities of Forming a Multiband Transmission Function Based on Multifrequency Acousto-Optic Diffraction

An analytical solution for the transmission function of noncoherent wideband radiation is obtained under acousto-optic (AO) filtering using a discrete set of monochromatic AO waves with a small spectral overlap. We studied characteristics of the AO transformation of a continuous spectrum of noncoherent radiation into a given set of discrete narrow bands of spectral transmission by excitation of a discrete set of sound frequencies. We carried out the analysis of transmission functions of individual channels taking into account a partial overlap of their spectra and possible intermodulation distortions. It is shown that a stationary value of the root-mean-square light power is found at the electronic output due to the photoelectric transformation and detecting diffracted light. Based on this, a necessary stationary, multiband, and nearly equidistant transmission function of a device can be formed by using a relevant spectrum of acoustic excitation. Peculiarities of this way of forming the multiband transmission function are revealed: the limitation of diffraction efficiency for an individual channel, the possibility of decoupling side lobes of adjacent channels, etc. A multiband acousto-optic filter (MAOF) was simulated that was based on a paratellurite monocrystal (TeO2), which was previously used for experimental optical encoding. The theoretical and experimental results are in gratifying agreement.

A Highly Integrated Independently Tunable Triple-Band Patch Antenna

A highly integrated tunable triple-band patch antenna is designed and fabricated. Two U-slots are cut in the same radiating patch to achieve triple-band performance. While the antenna miniaturization is obtained by loading one patch edge with metalized vias, theory of characteristic modes is adopted to explain the U-slots scaling. The antenna radiating patch size is only 0.1λ 0 × 0.17λ 0 . The operating frequencies can be independently tuned after properly inserting three varactor diodes into the radiating structure. The radiation patterns have similar unidirectional shapes with high stability of the resonant frequencies during the entire tuning of each band. Good agreement between simulation and measurement results is obtained. The antenna covers the following bands: 2.07-2.6 GHz, 2.86-3.57 GHz, and 4.59-5.39 GHz. The measured peak gains and efficiencies are 2.72 dBi and 62.6%, 2.76 dBi and 63.3%, and 2.87 dBi and 66.8%, respectively. Size reduction, multiband function, and independent tuning of three operating bands using only one antenna layer and one RF feedline are combined together to realize a compact and practical antenna.

Analysis and design of a triple band metamaterial simplified CRLH cells loaded monopole antenna

The design and analysis of meta-material inspired loaded monopole antenna for multiband operation are reported. The proposed antenna consists of multi resonators inspired from half mode composite right/left handed cells, which has a simple structure, compact size, and provides multiband functionalities. As a proof of concept, a triple band antenna covering all possible WiMAX operating bands, has been designed, fabricated, and characterized. The hosting monopole patch itself generates resonance for 3.3–3.8 GHz band, whereas the loaded metamaterial cells add extra resonance frequencies. The loading of two resonator cells introduces two extra resonances for 2.5–2.7 GHz and 5.3–5.9 GHz bands, respectively. The antenna's operating principle and design procedures with the aid of electromagnetic full wave simulation and experimental measurements are presented. The antenna has good omnidirectional patterns at all three bands. The monopole patch size is 13.5 × 6.5 mm2and the whole antenna size (including the feed line) is 35 × 32 mm2. Compared with conventional single band microstrip patch radiator, the radiator size of this antenna is only 8.5% at 2.5 GHz, 17% at 3.5 GHz, and 37% at 5.5 GHz.

Slot antenna with multiband functionality in wireless industrial applications

ABSTRACTA unique slot antenna, for multiband applications with asymmetric coplanar waveguide feed is proposed. Different form of strips is used as grounded slits for providing multiband functionality. By adopting the proposed strips length and size, much wider impedance band width is achieved in two bands. Beside that an asymmetric feeding method is applied with rectangular patch for generating new resonances and good matching. By utilizing this novel method, good impedance matching is seen in both bands. The antenna size is only about 40 × 40, which covers the frequency band from 4.8 to 6.5 GHz in band#1 and from 7.8 to 8.4 GHz in band#2 for VSWR <2. Furthermore, by variation of strips positions and patch lengths, the control of the impedance band width and resonances are steered. Both simulated and measured results are illustrated and compared with each other to guaranties antenna's performance. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1653–1655, 2015

Triband Filter Design Using Laminated Waveguide Cavity in LTCC

This paper demonstrates the flexibility and superiority of multilayer low-temperature cofired ceramic structures in realizing filters with multifunction features. A systematic synthesis technique is employed to develop triband laminated waveguide filters with minimum number of resonators and improved band allocation. By exploiting the multiple resonant modes inside a cavity, the coupling mechanisms and feeding design for different bands can be selectively controlled in accordance with the modal field distributions. Thus, the different passbands can be treated with different methodologies to achieve the multiband function with flexible band allocation. A triband filter operated at 30, 35, and 37 GHz with a fourth-order quasi-elliptic response for the first band and a split-type response for the last two bands is developed. It shows only four cavities are needed with the overall circuit size of 4.9 × 4.1 × 0.88 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Experimental and simulated results are in good agreement, both validate the design concept.

Novel Cross-Type Network for Wide-Tuning-Range Reconfigurable Multiband Antennas

This paper presents a cross-type network design with a novel reconfigurable functionality to realize a tunable multiband antenna. By attaching a reconfigurable network at the feeding port of a broadband antenna, multi-input impedance adjustment enables the production of multimatching operating bands. Each band can be independently controlled by a single component with a considerably wide tuning range and high selectivity. The experiments in this study involved using an ultra-wideband (UWB) antenna connected to the proposed cross-type network. The tunable antenna operates in a dual band offL(1.39 to 2.34 GHz) andfH(2.1 to 3.6 GHz) with tunable frequency ratios of 168% and 132%, respectively. The average bandwidths atfLandfHare approximately 50 MHz and 148 MHz, respectively, implying narrowband operation. The measured radiation pattern revealed that the tunable antenna exhibits a nearly omnidirectional radiation pattern at both 1.8 and 3.5 GHz. The network circuit architecture can be extended to the multiband function type by adopting this matching approach. The amount of shunt matches determines the number of operation bands.

Fractal H-shaped plasmonic nanocavity

Based on complementary fractal geometry structures, we design a novel infrared quasi-three-dimensional (3D) nanocavity with a localized enhanced field with multiband resonant frequencies. The fractals offer the nanostructure two important characteristics, multiband functionality and a subwavelength effect. The electric field, power flow, and the field intensity distributions are given to indicate the internal mechanism of the localized enhanced field in the nanocavity. Additionally, the effective medium method is established to retrieve the permittivity and impedance of the structure. It is shown that a strongly enhanced localized field is achieved in the nanocavity at two different resonant frequencies by using the finite difference time domain method. The field intensity in the nanocavity is enhanced by a factor of up to 60 times over that of the incident light because of the important contribution of the loss factor in the permittivity. The surface plasmon hybridization is thought to play an important role in the strong localized field enhancement. The multiband property and high localized intensity offer the nanocavity great potential for applications in surface enhanced Raman scattering and other nanoscale novel devices.

Reconfigurable Slot Antenna for Switchable Multiband Operation in a Wide Frequency Range

A reconfigurable antenna with switchable multiband functionalities is presented. The antenna operates one at a time at five adjacent frequency subbands in the upper ultrawideband (UWB) frequency band of 6.0-10.6 GHz. The switching from one subband to another is done electronically by means of five PIN diode switches. The antenna also has a nearly omnidirectional radiation pattern, with vertical polarization at each of its frequency subbands. Simulated and measured results are compared and are shown to be in good agreement.

Recent Advances in Multiband Printed Antennas Based on Metamaterial Loading

It is shown that printed antennas loaded with metamaterial resonators can be designed to exhibit multiband functionality. Two different antenna types and metamaterial loading are considered: (i) printed dipoles or monopoles loaded with open complementary split ring resonators (OCSRRs) and (ii) meander line or folded dipole antennas loaded with split ring resonators (SRRs) or spiral resonators (SRs). In the first case, multiband operation is achieved by series connecting one or more OCSRRs within the dipole/monopole. Such resonators force opens at their positions, and by locating them at a quarter wavelength (at the required operating frequencies) from the feeding point, it is possible to achieve multiple radiation bands. In the second case, dual-band functionality is achieved through the perturbation of the antenna characteristics caused by the presence of the metamaterial resonators. This latter strategy is specially suited to achieve conjugate matching between the antenna and the chip in radiofrequency identification (RFID) tags at two of the regulated UHF-RFID bands.

Analytical Evaluation of Tri-band Printed Antenna

Accepted: blished online: Abstract: Simulated design and analysis of a simple tri-band microstrip antenna is presented in this paper. A thin transmission line is used to excite the rectangular patch and FR4 epoxy with relative permittivity of 4.4 is used as substrate. To confirm the proficiency of proposed antenna, simulations have been performed in Ansoft HFSS (High Frequency Structure Simulator) a 3D electromagnetic field simulator, based on finite element method. Impedance bandwidths are determined on -10 dB at resonating frequencies of 2.4, 3.3 and 5.3 GHz. An introduced design covers the requisite bandwidth for IEEE Wireless Local Area Network (WLAN) standards: 802.11 a/n, b/g (Wi-Fi), Bluetooth, ZigBee, and 802.16e (WiMAX). Multiband functionality, small size, light weightiness, plain configuration and conformability are the advantages; making the proposed design a good contender for integration in handheld wireless devices.

Multi-Band Multi-Mode Microstrip Circular Patch Antenna Loaded With Metamaterial Structures

A microstrip circular patch antenna with multi-band multi-mode function is presented in this paper. Metamaterial structures including four curved lines added around the circular radiating patch and a circular ring of modified mushroom cells loaded under the radiating patch enable this property. Two monopole modes with omnidirectional radiation patterns in the azimutal plane and one patch mode with patch-like radiation pattern between them are excited by a single probe feed for this novel antenna. A prototype was designed and fabricated for verification. Both simulation and measurement results verify that this antenna is valuable in wireless communications for its low-profile structure and radiation pattern selectivity.

Bandwidth improvement of a zeroth-order resonant antenna for WiMax applications

A new multiband coplanar waveguide fed zeroth-order resonant (ZOR) antenna structure with improved bandwidth is proposed. This antenna achieves multiband functionality in five different frequency bands in the range of 2.5–5 GHz. The ZOR frequency is observed to be at 3.97 GHz. The bandwidth improvement, gain, and antenna efficiency at this frequency is found to be 3.28%, 1.9769 dB, and 73.42%, respectively. The proposed antenna is measured at antenna measurement facility, and results were compared with the simulated results. A good agreement between the measured and the simulated results validates the proposed design. The designed antenna proposed in this article holds potential applications in modern wireless communication systems which require multiband antennas with good radiation characteristics. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE 22:569–574, 2012.

Multi-segment MPA with T-feed for multi-band wireless communication

A new antenna structure comprising multiple radiating microstrip patches, representing a digital figure of eight, proximity fed by a microstrip line is proposed. On a double-layered substrate of FR4, this antenna achieves multi-band functionality in the range 3.2–13.51 GHz which covers IEEE 802.11a standard and other wireless communication systems. It achieves multi-band functionality through the introduction of short connecting metallic strips which connect the different elements of the main radiating structure. The reflection coefficient spectra and the radiation patterns are suggestive of reconfigurability in frequency and pattern. Details of the antenna design and simulation results of the reflection coefficients, voltage standing wave ratio bandwidth, gain and the radiation pattern of the proposed antenna are presented. A prototype has been developed and successfully implemented.