Showing papers on "Folded inverted conformal antenna published in 2015"

Dual-Band Textile MIMO Antenna Based on Substrate-Integrated Waveguide (SIW) Technology

Abstract: A dual-band textile antenna for multiple-input–multiple-output (MIMO) applications, based on substrate-integrated waveguide (SIW) technology, is designed. The fundamental SIW cavity mode is designed to resonate at 2.4 GHz. Meanwhile, the second and third modes are modified and combined by careful placement of a via within the cavity to enable wideband coverage in the 5-GHz WLAN band. The simple antenna topology can be fabricated fully using textiles in a planar form, ensuring reliability and comfort. Numerical and experimental results indicate satisfactory antenna performance when worn on body in terms of impedance bandwidth, radiation efficiency, and specific absorption ratio (SAR). In order to validate its potential for MIMO applications, two elements of the proposed SIW antenna are arranged in six configurations to study the performance in terms of mutual coupling and envelope correlation. It is observed that the placement of the shorted edges of the two elements adjacent to each other produces the lowest mutual coupling and consequently the best envelope correlation.

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

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

A Frequency- and Polarization-Reconfigurable Stub-Loaded Microstrip Patch Antenna

Abstract: A stub-loaded microstrip patch antenna with reconfigurability in both frequency and polarization is presented. Using 12 varactors with two independent voltages, reconfigurability is achieved in a fractional bandwidth of around 40% while allowing selection between circular polarization (CP) with both rotating senses and linear polarization (LP). The design is optimized based on an analytical model, which significantly speeds up the process while yielding reasonably accurate predictions. For illustration of the concept, an antenna is designed, optimized, and manufactured for reconfigurable operation in the 2.4–3.6 GHz frequency range. A good agreement between simulations and measurements is obtained which validates the proposed method. A full reconfigurability is demonstrated in the operation band with the ability to both tune the antenna to a given frequency and select a polarization state among left-hand or right-hand CP or various states of LP.

A Compact Planar Printed MIMO Antenna Design

Abstract: In this paper, we describe the design of a novel planar multiple-input-multiple-output (MIMO) antenna. The basic idea of the design is the development of a canonical two-port antenna that can be replicated and concatenated together to form MIMO antennas with arbitrary even numbers of ports. The design of the canonical element uses compact folded slots for the radiating elements but includes the use of field cancelation to enhance isolation by incorporating a coupling parasitic element. In addition by properly designing the coupling parasitic and the two-port antenna, coupling between canonical elements is also reduced allowing them to be concatenated together. The canonical element size is $27.5 \times 30\;{\rm mm}^2$ operating at 2.6 GHz and it can be packed together with high densities of up to 22 elements per square wavelength. To validate the design, results from 20-port planar printed MIMO antennas are presented operating at 2.6 GHz with a bandwidth of 100 MHz. The 20-port antenna has size of $1.3{\lambda}_{0} \times 0.69{\lambda}_{0}\;{\rm mm}^2$ providing an antenna density of 22 antenna in free space square wavelength ( ${\lambda}_{0}^{2}$ ). Even though the individual antennas are densely packed, all combinations of mutual couplings between ports exhibit better than 10 dB isolation. The antennas are printed on an FR-4 printed circuit board (PCB), which is a low-cost substrate and allows straightforward prototyping.

HF Band Shipboard Antenna Design Using Characteristic Modes

Abstract: The large wavelength of decameter wave brings a lot of practical difficulties to the design of shipboard antennas in high-frequency (HF) band. How to design conformal or even platform-embedded HF antennas raises us a new challenging topic. This paper proposes an approach to address such challenging problem through the combination of the characteristic mode (CM) theory with the structural antenna concept. 1) The CMs are solved to understand the resonant behavior of the ship platform. 2) We synthesize the radiating currents for designated radiation pattern by making use of the CMs of the ship platform. It allows the dominant radiating currents to locally distribute on the superstructure of the ship. Consequently, the superstructure becomes the main radiator. The modal solutions in CM theory ensure the efficiency of the synthesis procedure. 3) Nonprotruding slits are proposed to excite the synthesized currents. As the resultant HF shipboard antenna has no protruding elements around the ship, this design can be considered as either platform-conformal or platform-embedded. As an example, HF antenna on a realistic ship with broadside radiation pattern is designed. Simulation and experimental results on a 1:400 scale model demonstrate the effectiveness of the proposed approach in HF shipboard antenna designs.

Compact and Bandwidth-Enhanced Zeroth-Order Resonant Antenna

Abstract: In this letter, a simple bandwidth-enhanced zeroth- order resonant (ZOR) antenna is proposed. The presented antenna is composed of two unit cells of the composite right/left-handed (CRLH) artificial structure and operates in the series resonant mode. In order to enhance the operational bandwidth, in particular, the interdigital capacitor in a unit cell was properly designed so as to reduce the quality factor of the resonator while occupying a relatively small area. Additionally, to facilitate implementation of the short-circuited boundary condition, the coplanar waveguide (CPW) was applied to develop a via-less uniplanar antenna prototype. Experimental results show that the presented ZOR antenna achieves a 10-dB bandwidth of 15.1% and a peak radiation gain of 1.62 dBi with a compact size of $0.14{\lambda _0} \times 0.22{\lambda _0}$ at the operating frequency. Measured and simulated results are in good agreement.

The Effect of Changing Substrate Material and Thickness on the Performance of Inset Feed Microstrip Patch Antenna

Abstract: In order to design a microstrip patch antenna at first the designer is to select the substrate material and it’s thickness. So, if the designer has a clear conception about the effect of changing substrate material and it’s thickness on the performance of the antenna, it will be easier to design an antenna. Appropriate selection of dielectric material and it’s thickness is an important task for designing a microstrip patch antenna. This paper represents that how antenna performance changes when we vary substrate material and it’s thickness. The designed inset feed rectangular microstrip patch antenna operates at 2.4GHz (ISM band).

Proximity-Coupled Multiband Microstrip Antenna for Wireless Applications

Abstract: This letter presents a new design of a multiband microstrip antenna with a proximity-coupled feed for operating in the LTE2300 (2300–2400 MHz), Bluetooth (2400–2485 MHz), WiMAX (3.3–3.7 GHz), and WLAN (5.15–5.35 GHz, 5.725–5.825 GHz) bands. In addition, it also covers 6-dB impedance bandwidth across the UMTS (1920–2170 MHz) band. The proposed antenna consists of a corner-truncated rectangular patch with a rectangular slot, meandered microstrip feed, and defected ground plane. The antenna is fabricated using 0.8-mm-thick FR4 substrate with a dielectric constant of 4.4 and has a small size of only $27\times 24~\hbox{mm}^{2}$ . The antenna shows a stable gain over the operating bands and good radiation characteristics. The simulated and measured results are shown to have good agreements.

Substrate Integrated Waveguide Cavity-Backed Dumbbell-Shaped Slot Antenna for Dual-Frequency Applications

Abstract: In this letter, a novel dumbbell-shaped slot along with thin substrate integrated waveguide (SIW) cavity backing ( ${\rm height} ) is used to design dual-frequency slot antenna. The proposed design exhibits unidirectional radiation characteristics, high gain, high front to back ratio (FTBR) at each resonant frequency while maintaining low profile, planar configuration. The unique slot shape helps to introduce complex current distribution at different frequencies that results in simultaneous excitation of hybrid mode at higher frequency along with conventional ${{\rm TE}_{120}}$ mode in the cavity. Both conventional mode and the hybrid mode helps the modified slot to radiate at the corresponding resonant frequencies resulting in compact, dual-frequency antenna. A fabricated prototype is also presented which resonates at 9.5 GHz and 13.85 GHz with impedance bandwidth more than 1.5% at both resonant frequencies and gain of 4.8 dBi and 3.74 dBi respectively. The front-to-back ratio of the antenna are above 10 dB at both operating frequencies.

Microstrip Patch Antenna Temperature Sensor

Abstract: The resonant frequencies of a microstrip patch antenna are dependent on the dielectric constant of its substrate and the physical dimensions of its radiation patch. Both of these parameters are temperature-dependent. In this paper, we investigated the effects of temperature on the antenna resonant frequencies for the purpose of studying the microstrip patch antenna as a temperature sensor. First, the relationship between the antenna resonant frequency shift and the temperature change is derived based on the transmission line model. To validate the theoretical prediction, antenna sensors bonded on different metal bases were tested in a temperature chamber. By comparing the measured temperature-frequency relationship with the theoretical predictions, we discovered that the dielectric constant of the substrate is not only dependent on temperature but also influenced by the base material. After calibrating the thermal coefficient of the substrate dielectric constant using the measurement data, the differences between the measurements and the theoretical predictions were within the expected systematic error of the reference thermocouple, validating that a microstrip patch antenna can serve as a temperature sensor.

Inverted-F/Slot Integrated Dual-Band Four-Antenna System for WLAN Access Points

Abstract: A four-antenna system applicable to compact access points of wireless local area network is proposed. The antenna topology integrates an inverted-F antenna and a folded slot antenna in the same space to reduce sizes to $15.5~\hbox{mm} \times 7.5~\hbox{mm}$ . The inverted-F antenna operates in the 5 GHz HiperLAN band and the slot functions in the 2.4 GHz ISM band. Antenna tuning can be done without difficulty because the two are of different antenna types. Four antenna assemblies are placed at corners of a $50~\hbox{mm} \times 50~\hbox{mm}$ board to meet the multi-input multi-output operation needs. Since the element antenna exhibits moderate directivity and the four antennas are arranged in a rotational symmetry, decent isolations are achieved in both operation bands without additional decoupling measures. The antenna structure is fully planar and can be integrated within the printed circuit board, which makes it an attractive candidate for compact access point uses.

A D-Band Micromachined End-Fire Antenna in 130-nm SiGe BiCMOS Technology

Abstract: The design of a radiation-efficient D-band end-fire on-chip antenna utilizing a localized back-side etching (LBE) technique, as well as an antenna-in-package (AiP) on a low-cost organic substrate, is presented. Quasi-Yagi-Uda antennas are chosen for end-fire radiation because of their compact size. The on-chip antenna is realized in the back-end of the line (BEOL) process of a 130-nm SiGe BiCMOS technology, whereas the in-package antenna is realized in liquid crystal polymer (LCP) technology for comparison. The on-chip antenna design is optimized to meet both process reliability specifications and radiation performance, and corresponding design guidelines are provided. The fabricated on-chip antennas show the state-of-the-art performance with a peak gain of 4.7 dBi, simulated radiation efficiency of 82%, and measured radiation efficiency of 72%–76% using the gain/directivity (G/D) and wheeler-cap methods at 143 GHz. The antenna demonstrates a 3-dB gain bandwidth of more than 30 GHz and 10-dB impedance bandwidth greater than 20 GHz (14% impedance bandwidth). The measurements of the on-package end-fire antenna showed very comparable results with a peak measured gain of 6 dBi and a simulated and measured radiation efficiency of 92% and 86% at 143 GHz. These results demonstrate that highly efficient on-chip end-fire antenna implementation is possible in standard commercially available BiCMOS process.

Compact Zigzag-Shaped-Slit Microstrip Antenna With Circular Defected Ground Structure for Wireless Applications

Abstract: In this letter, a compact zigzag-shaped-slit rectangular microstrip patch antenna with circular defected ground structure (DGS) is designed for wireless applications. The probe-fed antenna consisting of a zigzag-shaped slit, dual T-shaped slits on either sides of a rectangular patch, and circular dumbbell-shaped defected ground plane is optimized. The antenna was able to generate three separate resonances to cover both the 2.45/5.28-GHz WLAN bands and the 3.5-GHz WiMAX bands while maintaining a small overall size of $40 \times 28 \times 3.175~\hbox{mm}^3$ . The return-loss impedance bandwidth values are enhanced significantly for three resonant frequencies. The designed antenna is characterized with better radiation patterns and potentially stable gain around 4–6 dBi over the working bands. Good agreement was obtained between measurements and simulations.

A Novel Microstrip Quasi Yagi Array Antenna With Annular Sector Directors

Abstract: A novel directional microstrip quasi Yagi array antenna is proposed to achieve a wide bandwidth with a low profile and a compact structure The array is composed of a driven circular sector and annular sector directors Arrays with both a single director and a dual director have been studied Measured results show that the proposed antenna provides a stable high gain in a wide bandwidth with a low profile of 15 mm ( $003\lambda_{0}$ at 58 GHz) For an array using a single annular sector director, an impedance bandwidth of 136% (510–585 GHz) is achieved with a peak gain of 82 dBi With two annular sector directors, the bandwidth is improved to 176% (505–602 GHz), and the peak gain is 10 dBi

Compact Multiband Antenna for Handsets With a Conducting Edge

Abstract: This communication proposes a compact multiband antenna fed by microstrip coupling for handsets with conducting edge applications. The antenna is composed of a U-shaped loop, an inserted open-end T-shaped slot, and a feed line with a compact antenna area. Three types of resonant modes are excited, namely loop mode, slot mode, and monopole mode. Parametric studies have been performed. After the related parameters are controlled, the bandwidth of this antenna has the potential to cover the mobile bands of GSM (824–960 MHz), DCS (1710–1880 MHz), PCS (1850–1990 MHz), UMTS (1920–2170 MHz), LTE bands (FDD–LTE bands 1–10, 15, 16, 18–20, 22, 23, 25–27, and 30 and TDD–LTE bands 33–43). Good radiation characteristics, such as gain and radiation efficiency, are obtained with these operating bands. In addition, the structure of the inserted slot antenna reduced the user’s hand effects on the radiation efficiency.

MIMO Antennas for Mobile Handsets

Abstract: This letter presents a pair of printed MIMO antennas for mobile handsets. With each antenna being a coupled fed monopole in a meandered shape, it is capable of covering GSM 1800/1900, UMTS, WLAN, and LTE frequency bands. The antennas are oriented diagonally at the nongrounded portion of the circuit board. The substrate used for the circuit board is FR4 with relative permittivity of 4.4 and loss tangent of 0.02. The overall volume of the circuit board is $110\times 65\times 0.8~\hbox{mm}^3$ , with each antenna occupying an area of $24\times14.5~\hbox{mm}^2$ . To improve the isolation between antennas, dual decoupling structures consisting of ground slots and inverted L ground branches that extend into the nongrounded portion are etched diagonally on the bottom layer of the substrate. The isolation achieved is better than 15 dB over all the frequency bands covered by each antenna leading to an envelope correlation coefficient of less than 0.02. The simulation and measured results are in good agreement.

Design of fractal based microstrip rectangular patch antenna for multiband applications

Abstract: In this paper a multiband fractal based rectangular microstrip patch antenna is designed. FR4 substrate having thickness of 1.58 mm is used as substrate material for the design of proposed antenna and microstrip feed line provides the excitation to the antenna. The antenna operating frequency range is from 1 to 10 GHz. The proposed antenna resonate at twelve different frequencies as 1.86, 2.33, 3.67, 4.57, 5.08, 6.06, 7.03, 7.75, 8.08, 8.84, 9.56 and 10 GHz and the return losses are −15.39, −16.48, −10.02, −17.29, −13.15, −23.41, −10.22, −11.28, −17.02, −10.94, −15.15 and −15.48 dB respectively. The proposed antenna is designed and simulated by using the Ansoft HFSS V13 (high frequency structure simulator) software.

Bandwidth enhancement of a CPW-fed monopole antenna with small fractal elements

Abstract: In this paper, a technique of adding small fractal elements to the polygon shape radiator of a CPW-fed monopole antenna for bandwidth enhancement is proposed and experimentally studied. Based on the multi-resonance effect of the fractal elements, three closely spaced resonant frequencies are produced over the antenna bandwidth which leads to coverage of the standard UWB bandwidth (3.1–10.6 GHz). Effects of increasing the number of the polygon sides on S 11 and radiation patterns are also investigated. Finally, three prototypes of the proposed antenna are fabricated and measured in order to verify the simulation results.

Miniaturised printed elliptical nested fractal multiband antenna for energy harvesting applications

Abstract: This study presents the design, optimisation, simulation and fabrication of a novel printed elliptical nested fractal (planar) antenna for multiband operation. The proposed antenna is intended to function as the receptor element in radio-frequency energy harvesting applications. The simple microstrip structure and the compact size of the antenna ease its fabrication and allow it to be integrated with other electronic circuitry. It consists of nested elliptical structures fed by 50 Ω microstrip line with complementary elliptical ground along with rectangular ground plane. The added Hilbert structures at both sides of the antenna feeding line on the top layer enhance its performance to operate in multi-frequency bands. This antenna exhibits good radiation and reflection characteristics at 910 MHz (global system of mobile (GSM 900)), 2.4 GHz (Bluetooth/wireless local area network), 3.2 GHz (Radiolocation, third generation (3G)), 3.8 GHz (for long-term evolution, 4G) and additional 5 GHz band (wireless fidelity signals). The overall dimension of antenna is 41 mm (width) × 44 mm (length) × 1.778 mm (thickness). To the best knowledge of the authors, this is the widest bandwidth antenna to be developed at these small dimensions covering major standards from 900 MHz up to 6 GHz for electromagnetic energy harvesting applications.

On Small Terminal MIMO Antennas, Harmonizing Characteristic Modes With Ground Plane Geometry

Abstract: multiple input–multiple output (MIMO) antenna systems are defined by fundamental figure of merits (FoM), such as branch imbalance, total efficiency, mean effective gain (MEG), and the correlation coefficient. Those FoM requirements are challenging, specially when applied to electrically small mobile devices, i.e., smart-phones, due to the form factor-reduced dimensions and multiplicity of adjacent frequency bands of operation. Uncorrelated antennas are especially important for MIMO antenna systems; other than few exceptional cases, the reduction of magnitude of complex correlation coefficient will increase the system capacity and data throughput. This work proposes an MIMO antenna system for mobile terminals, based on a realistic form factor and packaging implementation, with a very low magnitude of the complex correlation coefficient and an impressive isolation. An isolation better than 20 dB has been achieved using a folded monopole and a commonly adopted planar inverted F antenna (PIFA) on a platform with a very small form factor ( ${\bf{100}}\times {\bf{50}}\times {\bf{10}}\;\bf{mm}$ ). The proposed implementation is based on the synergy of two known techniques that consists in the: 1) reference ground plane geometry manipulation and 2) in the application of the characteristic mode theory to obtain orthogonal radiation modes. Since MIMO antenna systems at frequencies higher than 1.7 GHz are naturally proper isolated and decorreleated, this work demonstrates the proposed antenna topology enabling higher isolation and uncorrelated antenna system at 750 MHz, which is more difficult to achieve in form factors smaller than ${\bf{1}}\boldsymbol{\lambda}$ , while maintaining high total efficiency and adequate gain imbalance. In this paper, a simulation model and prototype ( ${\bf{1/4}}\boldsymbol{\lambda}$ long) measurement results are presented, demonstrating the implementation feasibility of such antenna system in realistic mobile device embodiment.

Electrically Small Resonant Planar Antennas: Optimizing the quality factor and bandwidth.

Abstract: The fundamental limitation (lower bound) on the quality factor (Q) of an electrically small antenna that fully occupies a spherical volume is defined by the well-known Chu limit. More recently, the subject of lower bounds for small antennas of arbitrarily shaped volumes has been given considerable attention in the literature. Gustafsson et al. were the first to present lower bounds for the Q of antennas of arbitrary volume. More significantly, they presented details on the optimum aspect ratios for minimizing the Q of electrically small antennas that fully occupy cylindrical volumes and planar areas. In previous works, we have described several electrically small-wire antenna designs that fully occupy spherical and cylindrical volumes and that are impedance matched and efficient and exhibit Qs that most closely approach the Chu limit and the Gustafsson limit, respectively.

Conformal VHF Log-Periodic Balloon Antenna

Abstract: A conformal log-periodic balloon antenna operating at a very high-frequency (VHF) band is presented in this communication. The antenna consists of eight conformal bowtie-dipole elements cross-fed by a parallel-strip transmission line and is then attached to the surface of a cylindrical balloon. After a detailed comparative analysis of the radiation performance of conformal strip dipole and bowtie dipole, a conformal log-periodic bowtie-dipole balloon antenna is designed. Simulated results show that its operating bandwidth ranges from 60 to 233 MHz with the voltage standing wave ratio (VSWR) less than 2 and a good end-fire radiation pattern of 5-dBi average gain. Measured results of a full-scale prototype fabricated with aluminum foils and a polyvinyl chloride balloon are in good agreement with simulated ones, which demonstrates the balloon antenna’s potential applications in VHF communication systems.

Dual-Band Elliptical Planar Conductive Polymer Antenna Printed on a Flexible Substrate

Abstract: In this communication, a fully organic dual-band antenna is presented. It consists of a coplanar waveguide coupled to an elliptical monopole antenna designed on a kapton substrate. This antenna is fabricated from a process, based on the use of a conductive polymer (Polyaniline) doped with multiwall carbon nanotubes, that has been optimized for this application. The flexibility of both kapton substrate and doped conductive polymer gives the antenna the ability to be freely crumpled paving the way to body-worn high data rate communications at microwave frequencies. Applications in wireless networks can also be addressed by using this kind of antennas. In this study, a comparison between the performance of an antenna under bending conditions (using a three-dimensional support) and its uncrumpled version is presented. We evaluate the crumpling effect on the resonant frequency, the bandwidth and the radiation patterns. A good agreement is observed between measurements and simulations data, even when the antenna is crumpled.

Design Guidelines Using Characteristic Mode Theory for Improving the Bandwidth of PIFAs

Abstract: It is well known that the bandwidth for a planar inverted-F antenna (PIFA) changes as the ground plane size changes. To gain insight into what causes bandwidth fluctuations, a process for applying characteristic mode theory to the finite ground plane and feed structure was developed. Four different PIFA designs are then evaluated to show how the modal significance of certain modes on the finite ground plane relate to the bandwidth minima and maxima for each PIFA. Next, finite ground planes are altered using the gained insight to enlarge the bandwidth for an antenna with a fixed maximum ground plane size. The goal of this work is to use the developed bandwidth analysis technique to inform the synthesis of PIFAs that require broader bandwidths.

A Compact Dual-Band Dual-Polarized Loop-Slot Planar Antenna

Abstract: This letter presents a compact dual-band dual-polarized loop-slot planar antenna. The antenna consists of a rectangular loop, a coplanar waveguide (CPW), and a microstrip line. The dual-band characteristic is realized using two different type resonant modes of the loop-slot antenna, namely, a loop basic mode in the lower band and a slot basic mode in the higher band. A CPW is used to excite vertical polarization modes and a microstrip line is used to excite horizontal polarization modes to achieve dual-polarized performance. The overall dimension of the prototype is only $55 \times 57~\hbox{mm}^{2}$ . The proposed antenna is built and tested. It has two common $-10~\hbox{dB}$ impedance bandwidths of 420 MHz (2.34-2.76 GHz) and 660 MHz (3.22-3.88 GHz) to cover 2.4 GHz WLAN band and 2.5/3.5 GHz WiMAX bands, respectively, and the isolation between the two ports is better than 21 dB in the dual-band. The antenna has stable radiation patterns and gains in both bands. The antenna also has the merits of compact dimension, low cross-polarization, and low cost.

Body-Insensitive Multimode MIMO Terminal Antenna of Double-Ring Structure

Abstract: In this paper, we propose a novel multimode multi-input multi-output (MIMO) antenna system composed of a dual-element MIMO cellular antenna and dual-element MIMO Wi-Fi antenna for mobile terminal applications. The antenna system has a double-ring structure and can be integrated with the metal frame of mobile terminals. With the multimode excitation, the MIMO cellular antenna can operate at 830–900 MHz, 1700–2200 MHz, and 2400–2700 MHz, for 2G, 3G, and LTE bands, respectively. The MIMO Wi-Fi antenna can cover two Wi-Fi bands from 2.4 to 2.5 GHz and from 5.2 to 5.8 GHz. The effect of a user’s body on the MIMO cellular antenna is investigated on CTIA standard phantoms and a real user. Since our antenna mainly operates in the loop mode, it has a much lower efficiency loss than conventional mobile antennas in both talking and data modes. Our theoretical analysis and experiments have shown that our design has low body loss and an attractive industrial design.

A Novel Low-Profile Hepta-Band Handset Antenna Using Modes Controlling Method

Abstract: It is a challenging and tough task to achieve and tune multiple frequencies for handset antennas in a small area. In this communication, we have proposed a novel modes controlling method to build and tune the handset antenna. By combining different modes of an open slot and different monopole branches, a hepta-band, covering GSM850, GSM900, DCS, PCS, UMTS, LTE2300, and LTE2500, handset antenna is achieved in a small area of 8 $\,\times\,$ 60 mm $^{2}$ . The most essential merit of the proposed antenna is that the related modes can be added step by step, according to the operating bands. The modes for the lower and upper bands can be easily tuned and optimized. We have also built a prototype of the proposed antenna to validate the design strategy. The tested results include reflection coefficient, radiation patterns, efficiency, and gain.

A Broadband Patch Antenna Array With Planar Differential L-Shaped Feeding Structures

Abstract: This study involved developing a differential patch antenna array featuring a wide bandwidth and improved radiation patterns The proposed patch array was fed by a planar, aperture-coupled, L-shaped feeding structure to achieve wideband operation The differential feeding structure improved the current distribution of resonant modes, substantially improving the symmetry of radiation patterns The array without differential excitation revealed an apparent deflected peak located at an observation angle of 10 $^{\circ} $ at 137 GHz However, using the proposed differential-fed structure, the location of this peak returned to 0 $^\circ $ The measured results indicated a wide impedance bandwidth of 215% and a stable gain varying from 103 to 1152 dBi over the frequency range of 116–15 GHz