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An approach of using the concept of CM (common mode) and DM (differential mode) to design two wideband antennas in a pair has been proposed. The two antennas in the antenna pair have wide bandwidth and high isolation, though they share the same radiator and total electric length of the antenna pair is just a half wavelength. A rigorous analysis has been presented to explain and illustrate the operating principle of the wideband antenna pair. An antenna design example operating in 5G New Radio (NR) N1, N2, N3, N7, N38 and N41 bands with frequency ranging from 1.71-2.69 GHz has been examined to demonstrate the effectiveness of the proposed approach. The simulated results, including S-parameters, antenna total efficiency and ECC (envelope correlation coefficient), are in good agreement with measured ones.

This article describes a compact dual-polarized endfire antenna array for fifth-generation (5G) millimeter-Wave (mm-Wave) mobile application. The dual-polarized endfire antenna element is constructed by a compact open-ended cavity with cavity mode for vertical polarization (VP) radiation and open-slot mode for horizontal polarization (HP) radiation. With the integrated design of VP and HP elements, the proposed antenna shows a much more compact size compared to existing schemes. To enhance the bandwidth of low-profile VP radiation, a slot is etched on the cavity to create a new mode for dual-resonance response, realizing a wide bandwidth of 24.5–29.5 GHz for both polarizations. In addition, radiation pattern modification techniques are employed to achieve good endfire beams with a high front-to-back ratio for both polarizations, thus enabling a high peak gain of 10.3 and 11.3 dBi for VP and HP, respectively. A wide beam scanning range of ±50° with realized gain above 7 dBi is realized at 27 GHz for both polarizations. In virtue of compact size, wide bandwidth, high gain, and good spatial coverage, the proposed design strategy is promising for future 5G mm-Wave mobile phones. [ABSTRACT FROM AUTHOR]

The human body's absorption of electromagnetic fields from communication enabled devices has consistently been a research topic for both researchers from universities and companies in the mobile communication industry. The absorption of electromagnetic fields could mainly result in two consequences: (a) antenna radiation efficiency of the device could deteriorate dramatically; and (b) a large amount of the radiated power could be dissipated into the human body, such as the hand, ear, scalp and brain, which is defined and described by Specific Absorption Rate (SAR). A comprehensive analysis of electromagnetic field absorption by the human body has been carried out to explain and answer some of the key questions in this area.

In this paper, an endfire dual-polarized phased array is introduced for 5G mobile applications, which operates from 26 GHz to 30 GHz with low profile of only 1.1 mm (${\bf 0.1\lambda _0}$ at 26 GHz) and small clearance of 3.5 mm. The array consists of interleaved substrate integrated waveguide (SIW) based vertical-polarized elements and notch type horizontal-polarized elements. The bandwidth of each SIW element is greatly improved by introducing a wide-band impedance transition, which is composed by parallel plate resonators and a metallic via in between. The notch elements have very compact size, which helps to keep the half-wavelength inter-element distance. The array has a planar structure and is easy to fabricate. The measured and simulated results align well with each other. [ABSTRACT FROM AUTHOR]

In this article, a new principle to overcome the blockage of metallic frames in mobile terminals to endfire millimeter-wave (mm-wave) arrays is proposed. The obstruction is solved by etching several slots in the top part of the frame. It is shown that the slots in the handset frame can further enhance the beam-steering gain of a mm-wave bow-tie array. A very small array-frame distance can also be realized without degrading much the array performance. Several considerations in the slot design are assessed first. A prototype of the PCB and frame has been built and the results show that the array is matched in the desired frequency bands of 24.25–27.5 and 27.5–28.35 GHz. The mm-wave array can scan 80° in the endfire direction, and the realized gain obtained is higher than 7 dBi in the operating frequency bands. At the same time, the frame performs as a sub-3 GHz dual-loop antenna. The covered bands are 760–980 and 1240–2870 MHz. [ABSTRACT FROM AUTHOR]

In this paper, a novel technique of collocating a millimeter-wave end-fire 5G beam steerable array antenna with a low-frequency planar inverted-F antenna (PIFA) is presented. In this technique, the low-frequency antenna can be transparent by using some grating strips between the low- and high-frequency antennas. A quad-element mm-wave array with end-fire radiation patterns operating in 22–31 GHz is integrated with a dual-band low-frequency PIFA in a mobile terminal. The novelty of this paper is the collocation of a high-frequency end-fire 5G antenna array with an old-generation low-frequency antenna, such as 4G in small space in the mobile terminal, without interfering with the radiation pattern and impedance matching of both low- and high-frequency antennas. The proposed 5G antenna covers 22–31 GHz and can scan ±50° with the scan loss of better than 3 dB. The coverage efficiency of the proposed mm-wave 5G antenna is better than 50% and 80% for a minimum gain of 4 and 0 dBi in 22–31 GHz, respectively. The gain of the high-frequency antenna array is better than 9.5 dBi at 28 GHz. The low-frequency antenna covers some practical 4G LTE bands from 740–960 MHz and 1.7–2.2 GHz bands. The measured results in both low and high frequencies agree well with the simulations. [ABSTRACT FROM AUTHOR]

Abstract: A novel technique to design a mobile phone antenna by using an ultrawideband (UWB) antenna configuration is proposed. The technique is validated with a novel printed slot antenna configuration. The slot is composed of a circle connected to a trapezoid and fed by means of a 50 Ω microstrip line connected to a patch with similar shape to the slot. An UWB antenna with size of 19 mm × 24 mm and measured −10 dB bandwidth of 2.97‐11.32 GHz is developed based on the configuration. When the configuration is applied in a system circuit board of 60 mm × 115 mm to design a mobile phone antenna, the simulated −6 dB bandwidths are 1.0‐1.2 GHz and 2.25‐15 GHz. To enhance antenna bandwidth, another slot with rectangular shape is etched in the ground plane, and the microstrip line is moved to the center of the circuit board and folded to distribute along the rectangular slot. The measured −6 dB bandwidths of the mobile phone antenna are 0.69‐1.09, 1.68‐2.75, 3.45‐3.52, and 3.62‐15 GHz. [ABSTRACT FROM AUTHOR]

In this letter, a planar loop-monopole reconfigurable antenna is proposed for mobile handsets with a relative compact dimension of 60 × 10 × 0.8 mm3. A novel coverage strategy is proposed to utilize the loop mode for the low and the high bands (LTE700, GSM850, GSM900; LTE2300, WLAN, LTE2500) and the strip monopole mode for the medium band (DCS, PCS, UMTS). As a result, a nona-band coverage for 2G/3G/4G bands is achieved within limited space. Only one p–i–n diode is used with a simple bias circuit to avoid high insertion loss. With the proposed compact structure, the antenna is suitable for wideband smartphone applications. A prototype of the proposed antenna is fabricated and measured to verify the design strategy. The measured results match well with simulation with acceptable radiation efficiency in the covered bands. Especially, the efficiency in the low band is higher than 70%. [ABSTRACT FROM AUTHOR]

The current demand in the handset antenna field requires multiband antennas due to the existence of multiple communication standards and the emergence of new ones. At the same time, antennas with reduced dimensions are strongly required in order to be easily integrated. In this sense, the paper proposes a compact radiating system that uses two non-resonant elements to properly excite the ground plane to solve the abovementioned shortcomings by minimizing the required Printed Circuit Board (PCB) area while ensuring a multiband performance. These non-resonant elements are called here ground plane boosters since they excite an efficient mode of the ground plane. The proposed radiating system comprises two ground plane boosters of small dimensions of 5 mm x 5 mm x 5 mm. One is in charge of the low frequency region (0.824-0.960 GHz) and the other is in charge of the high frequency region (1.710-2.170 GHz). With the aim of achieving a compact configuration, the two boosters are placed close to each other in a corner of the ground plane of a handset device (concentrated architecture). Several experiments related to the coupling between boosters have been carried out in two different platforms (barphone and smartphone), and the best position and the required matching network are presented. The novel proposal achieves multiband performance at GSM850/900/1800/1900 and UMTS.

A novel slot antenna configuration is proposed for applications on mobile terminals. The slot has both ends opened and can be placed on circuit board edges or incorporated with a handset's metal body. The antenna is loaded with one capacitor at the slot's opening and an inductor right next to the feed. Functions of loadings include size reduction, band broadening, and matching improvement. A compact design of 15 mm × 5 mm is devised for dual-band WLAN uses. Simulated and measured results validate that good matching and radiation efficiency are achieved with moderately directive patterns in both bands. A two-antenna scheme is also provided for MIMO uses. A mobile device can take advantage of the proposed antenna's compact volume and directive pattern to achieve good isolation and diversity performances. [ABSTRACT FROM AUTHOR]

The metal body handset initiates various antenna design challenges. An assembly of two slots is proposed for long-term evolution (LTE) uses on metal body handsets. Several novel techniques are devised to address LTE operation needs. The slot openings are placed on the metal rim to minimize visual intrusion. The two-end open LTE high band (1700~2700 MHz) slot excites multiple adjacent resonances to stitch a broad operation band. The other one-end open slot adopts a coupled feed to provide a broad LTE low band (690~960 MHz). An unconventional two-branch feed network is proposed. Its frequency selective characteristic allows excitations of the two slots using a common feed. Parametric studies and tests that emulate the actual handset environment were conducted. Results demonstrate that the proposed antenna is resilient toward operation scenario changes and yields stable performances. [ABSTRACT FROM PUBLISHER]

In this paper, a novel six-mode loop antenna covering 660–1100, 1710–3020, 3370–3900, and 5150–5850 MHz has been proposed for the application of long-term evolution (LTE) including the coming LTE in unlicensed spectrum and LTE-Licensed Assisted Access. Loop antennas offer better user experience than conventional planar inverted-F antennas (PIFAs), inverted-F antennas (IFAs), and monopole antennas because of their unique balanced modes ( $1\lambda $ , $2\lambda , \ldots $ ). However, the bandwidth of loop antennas is usually narrower than that of PIFA/IFA and monopole antennas due to these balanced modes. To overcome this problem, a novel monopole/dipole parasitic element, which operates at an unbalanced monopole-like $0.25\lambda $ mode and a balanced dipole-like $0.5\lambda $ mode, is first proposed for loop antennas to cover more frequency bands. Benefiting from the balanced mode, the proposed parasitic element is promising to provide better user experience than conventional parasitic elements. To the best of the authors’ knowledge, the balanced mode for a parasitic element is reported for the first time. The proposed antenna is able to provide excellent user experience while solving the problem of limited bandwidth in loop antennas. To validate the concept, one prototype antenna with a size of $75 \times 10\times 5$ mm3 is designed, fabricated, and measured. Both simulations and experimental results are presented and discussed. Good performance is achieved. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM PUBLISHER]

ABSTRACT Multi-input multi-output (MIMO) technology will enable high-data rates in wireless devices to allow speech and video calls to streaming media and web browsing all over a common platform. MIMO technology needs M antennas both in transmission and reception. As the space in a wireless device is limited, including M antennas is a challenge. To face such challenge, a MIMO antenna system is proposed which comprises two small nonresonant elements operating in the frequency region 824-960 MHz and two identical elements operating at 1710-2170 MHz. The size of each of the nonresonant elements is only 5 × 5 × 5 mm3. The proposed MIMO system is analyzed in terms of bandwidth, efficiency, correlation, and multiplexing efficiency. MIMO capacity is measured in a reverberation chamber considering a free-space Rayleigh scenario and also including the effect of a phantom head and hand. The results reveal that the proposed MIMO system provides capacity close to the ideal bound while having a small size and able to operate at several 2G, 3G, and 4G long term evolution standards. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:183-190, 2015 [ABSTRACT FROM AUTHOR]

The current demand in the handset antenna field requires multiband antennas due to the existence of multiple communication standards and the emergence of new ones. At the same time, antennas with reduced dimensions are strongly required in order to be easily integrated. In this sense, the paper proposes a compact radiating system that uses two non-resonant elements to properly excite the ground plane to solve the abovementioned shortcomings by minimizing the required Printed Circuit Board (PCB) area while ensuring a multiband performance. These non-resonant elements are called here ground plane boosters since they excite an efficient mode of the ground plane. The proposed radiating system comprises two ground plane boosters of small dimensions of 5 mm x 5 mm x 5 mm. One is in charge of the low frequency region (from 0.824 GHz to 0.960 GHz) and the other is in charge of the high frequency region (1.710 GHz-2.170 GHz). With the aim of achieving a compact configuration, the two boosters are placed close to each other in a corner of the ground plane of a handset device (concentrated architecture). Several experiments related to the coupling between boosters have been carried out in two different platforms (barphone and smartphone), and the best position and the required matching network are presented. The novel proposal achieves multiband performance at GSM850/900/1800/1900 and UMTS. [ABSTRACT FROM AUTHOR]

New ways of achieving small, multiband, multifunctional, and standard solutions for mobile handset antennas are demanded in the current wireless market. A non-resonant element of 5 mm × 5 mm × 5 mm, a matching network, and a 100 mm × 40 mm slotted ground plane are proposed to satisfy mobile market demands that require multiband operation and small antenna solutions. The main advantage of the proposed design is that with only one non-resonant element of considerably small size (0.015λ, 900 MHz), the handset is capable of providing operation at mobile bands. [ABSTRACT FROM AUTHOR]

A compact internal antenna design applicable to handheld digital TV receivers is proposed. Its operation bandwidth extends from 470 MHz to 860 MHz, which covers most terrestrial digital TV broadcasting bands. The antenna sizes protruding from the ground plane are 80\ mm\times 15\ mm\times 10\ mm only and can fit in most palm-sized terminals. Major geometric features include a 3D folding structure that reduces the antenna footprint, a parasitic element that induces additional modes, and a folded microstrip line near the feed that improves the matching condition. The proposed design employs various methods to create multiple resonances in a confined antenna volume. Yet, a consistent radiation pattern is achieved over the operation band with decent efficiency performance. This is done by exciting several resonant modes within and adjacent to the desired band. Though the resonances take places at different antenna parts, most radiation comes from the current near the feed. The resulting antenna acts as a short electric dipole at all frequencies. Also, an abrupt efficiency roll-off is setup at the upper band limit to reduce interference from the nearby mobile service band. Rigorous studies were conducted to associate its superior performance features with implemented techniques. [ABSTRACT FROM PUBLISHER]

Reconfigurable multiple-input multiple-output (MIMO) antennas have the potential to improve the performance of a MIMO antenna system operating in a dynamic environment. This paper presents a reconfigurable MIMO antenna that utilizes two tunable parasitic elements that manipulate the characteristic modes of the structure to provide pattern diversity. Simulation studies and calculation of envelope correlation coefficients from this two-port antenna confirm that the radiation patterns are orthogonal to each other in each of the two states of the antenna, as well as between the two states. Measured two-port S-parameters of a prototype employing switched PIN diode loading correspond well with simulations. Radiation pattern measurements in the two principal planes indicate overall correlation with simulations. [ABSTRACT FROM PUBLISHER]

Multi-input and multi-output (MIMO) technology will enable high-data rates in wireless devices to allow speech and video calls to streaming media and web browsing all over a common platform. MIMO technology needs M antennas both in transmission and reception. Because the space in a wireless device is limited, including M antennas is a challenge. To face such challenge, a MIMO antenna system is proposed, which comprises a multiband monopole antenna (35 × 15 mm2) and two small nonresonant elements, each one operating in a particular frequency region: 824-960 and 1710-2170 MHz. The size of each of the nonresonant elements is only 5 × 5 × 5 mm3. The proposed MIMO system is analyzed in terms of bandwidth, efficiency, correlation, and multiplexing efficiency. MIMO capacity is measured in a reverberation chamber considering a free-space Rayleigh scenario and also including the effect of a phantom-head and hand. The results reveal that the proposed MIMO system provides capacity close to the ideal bound, whereas having a small size and able to operate at several 2G, 3G, and 4G (long-term evolution) standards. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1076-1084, 2014 [ABSTRACT FROM AUTHOR]

An antenna system comprising two closely spaced chip antennas is proposed for dual-band wireless LAN uses. The distance between two chips is 12 mm and the spacing between antenna feeds is 1 mm only. Yet, superior isolation performance is achieved in both operation bands. A novel isolation enhancing measure is implemented for the higher 5 GHz band, which is done by adding a pair of open-ended stubs next to antenna feeds. The stub pair functions as an all-stop filter and elevates the port isolation. Rigorous simulation works were conducted to associate antenna geometry with performance features. Results such as impedance matching, isolation, and radiation patterns were examined jointly to identify mechanisms of its decoupling and diversity features. Antenna diversity assessment measures including the envelope correlation coefficient and the effective diversity gain were derived. Results demonstrate that the proposed compact two-antenna configuration suits well to the diversity antenna need on portable devices. [ABSTRACT FROM AUTHOR]

ABSTRACT In this article, a simple printed monopole slot antenna with two parasitic shorted strips (a longer parasitic shorted strip and a shorter parasitic shorted strip) for penta-band wireless wide area network operation in the slim mobile phone is presented. The monopole slot has a length of 40 mm only and is disposed near the bottom edge of the system ground plane of the mobile phone with a small distance of 6.5 mm. By adding longer parasitic shorted strip connected to the bottom corner edge of the system ground plane, good excitation of the monopole slot antenna at its fundamental (quarter-wavelength) mode and chassis dipole-type mode of the system ground plane can be obtained. The shorter parasitic shorted strip contributes additional resonant mode to the antenna. The excited resonant modes form two wide operating bands to cover the GSM850/900 operation (824-960 MHz) and GSM1800/1900/WCDMA Band I operation (1710-2170 MHz), respectively. Details of the proposed antenna are presented. The specific absorption rate results for the antenna with the presence of the head and hand phantoms are also studied. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2835-2841, 2013 [ABSTRACT FROM AUTHOR]

ABSTRACT An onboard printed WWAN/LTE antenna of simple structure disposed in a small clearance of 8 × 36 mm2 in the ground plane of shaped circuit board in a slim handset is presented. The shaped circuit board has a large rectangular notch such that the battery of the handset can be embedded therein to decrease the thickness of the handset. It is shown that, compared to the traditional simple circuit board, the shaped circuit board can lead to much enhanced bandwidth of the antenna disposed thereon. This is mainly because stronger surface currents on the ground plane of the shaped circuit board can be excited, which greatly helps improve the operating bandwidth of the antenna disposed thereon. By properly short-circuiting the metal enclosing of the battery and the metal midplate that can be used to provide the handset with structural support, stronger excited surface currents on the ground plane of shaped circuit board can still be obtained. The proposed design makes a simple, small-size printed inverted-F antenna capable of providing two wide operating bands to cover the GSM850/900 bands (824-960 MHz) and GSM1800/1900/UMTS/LTE2300/2500 bands (1710-2690 MHz). Further, the proposed design can provide good antenna efficiency and meet the specific absorption rate regulations of less than 1.6 W/kg for 1-g head tissue as well. Detailed results of the proposed design are presented and discussed. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2254-2261, 2013 [ABSTRACT FROM AUTHOR]

ABSTRACT Miniature and multiband internal antenna systems are strongly required in emergent multifunction wireless devices. Recent techniques are focused on properly exciting ground plane radiation modes through nonresonant elements. These solutions remove the need of including quarter-wavelength resonant antennas featured by a considerable size. Nevertheless, in this new scenario, the complexity moves toward not only the reduction of the size of the elements used to excite the ground plane mode but also to the simplification of the radiofrequency system used to attain impedance matching. This article proposes the use of distributed systems based on nonresonant elements for solving the bandwidth and efficiency limitations of previous solutions while adding robustness to hand loading effects. Two different feeding schemes, an in-phase and an out-of-phase feeding scheme are simulated, measured, and compared in free-space as well as regarding the presence of a phantom hand. The proposal provides octo-band operation and attains a radiating system robust to hand loading effects capable of properly operating in nine communication standards, LTE700, GSM850, GSM900, DCS, PCS, UMTS, LTE2100, LTE2300, and LTE2500. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2307-2317, 2013 [ABSTRACT FROM AUTHOR]

An LTE MIMO antenna array, which is adaptive to the effects of the user's body, is presented for mobile terminals. The bands of 750–960 MHz and 1700–2700 MHz are covered with a good efficiency in free space. Three kinds of user effects are studied, namely, “SAM head and PDA hand,” “PDA hand,” and “dual hands.” The array is formed by selecting the best two elements out of four, with the two ports and grounding points of the other two elements open. The user effects on MIMO channel capacity are reduced through the adaptive selection of two optimal antenna elements. The total efficiency, envelope correlation coefficient, and multiplexing efficiency are presented for the three kinds of user effects. In the lower band, the decreased correlation due to the optimal selection improves the multiplexing efficiency. The underlying physical mechanisms and some general rules are discussed. The specific absorption rate (SAR) in the “SAM head and PDA hand” case is studied. Experiments for the three kinds of user effects are also carried out. [ABSTRACT FROM PUBLISHER]

Multiband and small antennas are strongly demanded in current wireless handheld or portable devices that require multiband operation. Nowadays, trends are focused on exciting ground plane radiation modes in order to reduce as much as possible the volume devoted to the antenna element. This paper studies different geometries for determining which one better excites a ground plane radiation mode at different frequency regions. The results demonstrate that a non-resonant pad element attains the best tradeoff between performance and geometry complexity. A multiband antenna system featuring small coplanar pad elements is proposed for providing operation at the communication standards LTE700 (698–787 MHz), GSM850 (824–894 MHz), GSM900 (880–960 MHz), GSM1800 (1710–1880 MHz), GSM1900 (1850–1990 MHz), UMTS (1920–2170 MHz), LTE2100 (1920–2170 MHz), LTE2300 (2300–2400 MHz), LTE2500 (2500–2690 MHz) as well as at the satellite positioning systems GPS (1575 MHz), Galileo L1 (1559–1591 MHz), Glonass (1592–1609 MHz). A radiofrequency system comprising broadband matching networks is included to provide the required impedance bandwidth. Numerical results give physical insight into the behavior of the proposed planar element. A prototype is built to demonstrate the feasibility of the proposal. The proposed radiating system is appealing for the new wireless handheld devices due to its small size (153 mm^2), planar profile, and multiband performance. [ABSTRACT FROM PUBLISHER]

An integrated antenna array comprising two decoupled multiband WWAN/LTE antennas having an isolation ring strip embedded therebetween and all disposed on a same FR4 substrate of small size 10 × 70 mm2 is presented. The two decoupled antennas cover the 824-960/1710-2690 MHz bands for the GSM850/900 and GSM1800/1900/UMTS/LTE2300/2500 operations and are promising to be mounted at the bottom edge of a smartphone for dual wireless wide area network (WWAN) operation for dual-talk function or for long term evolution (LTE) multiple-input multiple-output operation. The measured transmission coefficient S21 between the two antennas is less than −15 dB over both the 824-960 and 1710-2690 MHz bands, and the envelop correlation coefficient is less than about 0.03 over both bands. Port-decoupling of the two antennas is obtained because the excited surface currents on the system ground plane of the smartphone between the two antennas are decreased owing to the isolation ring strip attracting some of the same. In addition to good isolation obtained, the antenna efficiencies are better than about 40 and 50% over the lower and upper bands, respectively. Details of the decoupled WWAN/LTE antennas are described. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1470-1476, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27654 [ABSTRACT FROM AUTHOR]

A simple printed multiband antenna with parasitic-element design for multi-standard handheld terminals in mobile communications is presented. The proposed antenna performs three resonance modes covering six bands of wireless standards, including GSM, GPS, DCS, PCS, UMTS, and LTE 2300/2500. In geometry, the antenna simply consists of two metal stubs. One is an L-shaped driven stub working as a feeder and an embedded transmission line. The other is a U-shaped parasitic stub working as a radiator. With fully printed and simple configuration, the proposed antenna design is cost effective in manufacturing and easy to optimize for different frequency bands. Parametric studies and the design rule are included. The antenna occupies an area of 18\,\times\,37 mm^2 on top of a system board. This communication covers the details of the antenna design, working principle, and the performances of simulation and measurement. [ABSTRACT FROM PUBLISHER]

Hand loading usually degrades the performance of handset antennas. With the aim of providing a solution robust to the human presence, this paper discloses a distributed antenna system fed in-phase capable of mitigating undesirable hand loading effects while providing enhanced performance. The solution consists of a passive array of two resonant coplanar monopole antennas inspired in the Hilbert geometry. Input impedances of both monopoles are combined into a single input–output port through two transmission lines featuring equal phases. This combination allows not only improving the performance of the radiating system with respect to that attained by a single monopole antenna, but also providing a symmetric solution immune to the finger location. The solution is compared with a single monopole and a distributed antenna system fed out-of-phase. Simulated and measured results demonstrate that the proposed design is capable of providing operation in the communication standards GSM850/GSM900 as well as in the UHF part of the LTE-Advanced while maintaining the same electromagnetic performance with certain independence of the finger location. [ABSTRACT FROM PUBLISHER]

The ground plane of a handset device plays an important role in the radiation process. As a consequence, through a ground plane modification, it is possible to obtain a multiband performance while keeping small antenna dimensions. Numerical simulation using Method of Moments has been used to understand the effect of the slots and a prototype has been built to validate the solution. The proposal consists in a multiband planar monopole handset antenna featuring a small area of 13 mm × 11 mm with a slotted ground plane operating in multiple communication standards (GSM850, GSM900, DCS, PCS, UMTS, LTE2300, WiMAX, Bluetooth, and Wi-Fi). Thanks to the presence of the slots, the bandwidth and efficiency results have been significantly improved. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:173-180, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27232 [ABSTRACT FROM AUTHOR]

An internal WWAN (824-960/1710-2170 MHz) handset antenna suitable to be disposed at a small notch of 35 × 6 mm2 in the system ground plane of the handset is presented.Also, the antenna has a low profile of 3 mm above the main circuit board on which the system ground plane is printed. That is, the antenna occupies a small volume of 35 × 6 × 3 mm3 or 0.63 cm3 only (much less than 1 cm3). To fit in the small notch, a quarter-wavelength gap-coupled loop antenna is applied, which not only can be configured into a compact configuration but also can be in proximity to the surrounding ground plane. With the aid of a matching network, which is comprised of a series chip inductor and a band-stop matching circuit, two wide operating bands to, respectively, cover the GSM850/900 and GSM1800/1900/UMTS operation are obtained. Details of the proposed antenna are described. The applied techniques in achieving wideband operation with a small antenna size are discussed. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2498-2503, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27125 [ABSTRACT FROM AUTHOR]

The performance of handset antennas is strongly affected by the user interaction. In particular, the close proximity of the user's hand when holding the phone usually degrades the behavior of the antenna by introducing detuning effects and efficiency decrements. With the aim of mitigating such negative effects, the present paper proposes a distributed antenna system comprising three monopoles strategically arranged along the ground plane of a wireless handheld device. This configuration not only improves the performance of the radiating system with respect to that attained with a single monopole antenna or a distributed antenna system of two monopoles, but also increases its robustness to the hand loading effect. In order to assess the benefits of the proposed technique, simulated and measured results in free-space as well as regarding the presence of a hand phantom are compared with previous techniques based on a single monopole and a distributed antenna system of two monopoles. The experimental results demonstrate that the proposed distributed antenna system of three monopoles improves the bandwidth (34% for \ SWR \leq 3 (693–978 MHz)), the efficiency in free-space, and becomes more robust to the hand loading effects than a single monopole solution and a distributed system of two monopoles. [ABSTRACT FROM PUBLISHER]

In this paper, details are given on a novel measurement device for radio propagation-channel measurements. To avoid measurement errors due to the conductive cables on small terminal antennas, as well as to improve the handling of the prototypes under investigation, an optical measurement device has been developed. It utilizes thin, light, and flexible glass fibers as opposed to heavy, stiff, and conductive coaxial cables. This paper looks at the various system parameters such as overall gain, noise figure, and dynamic range and compares the solution to other methods. An estimate of the device accuracy is also given. Selected parts of the circuitry are given in more detail. Typical measurement results are also shown. [ABSTRACT FROM AUTHOR]

A novel internal handset antenna formed by a monopole slot and a monopole strip for the wireless wide area network (WWAN) operation in the 824-960 and 1710-2170 MHz bands is presented. The monopole strip is disposed in the monopole slot, and both are embedded in the system ground plane of the handset with a small board space of 9 × 40 mm2 at about the bottom edge of the circuit board. The monopole strip serves as a feed for the monopole slot and also functions as an efficient radiator. In the proposed design, the monopole slot generates a quarter-wavelength slot mode in the antenna's lower band, while the monopole strip contributes its quarter-wavelength mode in the antenna's upper band. By including a vertical strip that can be enclosed inside the handset casing or be a part of the bezel surrounding, the periphery of the handset casing and connected to the bottom edge of the system ground plane, the impedance matching of the excited slot mode can be greatly improved. In this case, the proposed antenna can provide two wide operating bands with good impedance matching to cover the pentaband WWAN operation. Detailed operating principle of the integrated monopole slot and monopole strip for the internal WWAN handset antenna is described. The proposed antenna is also fabricated and obtained results are presented and discussed. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1718-1723, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26870 [ABSTRACT FROM AUTHOR]

An electrically small, two-element, parasitic array (Yagi) antenna is proposed for an active 433.92-MHz RFID handheld reader. The antenna is composed of a square-shaped driver and director. The circular polarization is achieved by pulling the driver and pushing the director at one side. The sense of the antenna can be changed easily by pushing the driver and pulling the director at the same side. The total volume of the antenna is 115 mm\,\times \,115 mm\,\times \,13.8 mm (0.166 \lambda \times 0.166 \lambda \times 0.02 \lambda), and the electrical size is a kr of 0.75. The maximum measured realized gain is 3.5 dBic. [ABSTRACT FROM PUBLISHER]

Analysis of the antenna correlation at the design stage is made, and then compared to real life performance in a typical propagation environment and in typical use cases. A traditional design flow is followed and conclusions are made on the performance of several handsets. These conclusions are then contrasted to measurements and an explanation is sought for the variations. It is concluded that correlation estimation and optimization at the design stage, using conventional methods, brings little benefit in real life situations. Impact on channel capacity has been the figure of merit. [ABSTRACT FROM PUBLISHER]

A folded loop-inverted F reconfigurable antenna for mobile phone applications is designed and the obtained results are discussed in this communication. It is shown that loop antenna mode and an inverted F antenna (IFA) mode are controlled by only one p-i-n diodes with simple bias circuit. The impedance can be matched by adopting a matching bridge for both the loop and IFA modes. In a compact volume of 60\,\times\,5\,\times\,5 mm^3, the proposed antenna operates in hepta-band, including GSM850, GSM900, GPS, DCS, PCS, UMTS and WLAN, with the return loss lower than 6 dB. A prototype of the proposed antenna is fabricated, measured, and obtained results including return loss, efficiency and gain, are presented. [ABSTRACT FROM PUBLISHER]

A coupled-fed dual-loop antenna capable of providing eight-band WWAN/LTE operation and suitable to integrate with a USB connector in the mobile handset is presented. The antenna integrates with a protruded ground, which is extended from the main ground plane of the mobile handset to accommodate a USB connector functioning as a data port of the handset. To consider the presence of the integrated protruded ground, the antenna uses two separate shorted strips and a T-shape monopole encircled therein as a coupling feed and a radiator as well. The shorted strips are short-circuited through a common shorting strip to the protruded ground and coupled-fed by the T-shape monopole to generate two separate quarter-wavelength loop resonant modes to form a wide lower band to cover the LTE700/GSM850/900 operation (704–960 MHz). An additional higher-order loop resonant mode is also generated to combine with two wideband resonant modes contributed by the T-shape monopole to form a very wide upper band of larger than 1 GHz to cover the GSM1800/1900/UMTS/LTE2300/2500 operation (1710–2690 MHz). Details of the proposed antenna are presented. For the SAR (specific absorption rate) requirement in practical mobile handsets to meet the limit of 1.6 W/kg for 1-g human tissue, the SAR values of the antenna are also analyzed. [ABSTRACT FROM AUTHOR]

In this letter, an internal folded reconfigurable loop antenna for mobile handset applications is designed, built, and tested. Two operating states with different frequencies are obtained by switching the shorting pins of the loop. The bandwidth of the proposed antenna has been increased by adopting a matching bridge. In a compact volume of 60\times 5\times 5~\mm^3, the proposed antenna operates in heptaband, including GSM850, GSM900, GPS, DCS, PCS, UMTS, and WLAN, with the return loss lower than 6 dB. The efficiency and gain with the p-i-n diodes with their bias circuit are also measured and analyzed. [ABSTRACT FROM PUBLISHER]

The increasing demand for multifunctional wireless devices has fostered the need to reduce the space devoted to the antenna in order to favor the integration of multiple and new functionalities. This fact becomes a challenge for the handset antenna designers who have to develop antennas capable of providing multi-band operation constrained by physical limitations. This proposal consists in a radiating system capable of providing multi-band operation without the need of an antenna element, by properly exciting the efficient radiation modes associated to the ground plane structure. In this sense, the typical volume devoted to a handset antenna is reduced by a factor of 20. The electrical model approximation of the radiating structure leads to the radiofrequency system design able to provide multi-band operation. The feasibility of the proposal has been tested by electromagnetic simulations as well as by experimental measurements regarding the main antenna parameters: reflection coefficient, efficiency, and radiation patterns. Furthermore, the human head interaction concerning biological compatibility in terms of SAR (Specific absorption rate) has been measured and a solution for its reduction is presented. As a result, a promising standard solution for a radiating system capable to operate in the main communication standards GSM850, GSM900, DCS, PCS and UMTS is provided with a volume reduction factor around 20. [ABSTRACT FROM AUTHOR]

A small-size coupled-fed loop antenna suitable to be printed on the system circuit board of the mobile phone for penta-band WWAN operation (824–960/1710–2170 MHz) is presented. The loop antenna requires only a small footprint of 15\,\times 25~mm^2 on the circuit board, and it can also be in close proximity to the surrounding ground plane printed on the circuit board. That is, very small or no isolation distance is required between the antenna's radiating portion and the nearby ground plane. This can lead to compact integration of the internal on-board printed antenna on the circuit board of the mobile phone, especially the slim mobile phone. The loop antenna also shows a simple structure; it is formed by a loop strip of about 87 mm with its end terminal short-circuited to the ground plane and its front section capacitively coupled to a feeding strip which is also an efficient radiator to contribute a resonant mode for the antenna's upper band to cover the GSM1800/1900/UMTS bands (1710–2170 MHz). Through the coupling excitation, the antenna can also generate a 0.25-wavelength loop resonant mode to form the antenna's lower band to cover the GSM850/900 bands (824–960 MHz). Details of the proposed antenna are presented. The SAR results for the antenna with the presence of the head and hand phantoms are also studied. [ABSTRACT FROM AUTHOR]