Phone Antenna Research Articles

Large Ad Hoc Shielded Room with Removable Mode Stirrer for Mobile Phone Antenna Tests

Reverberation chambers (RC) are widely used for measuring antenna performance and parameters for MIMO systems. RCs for mobile phone antenna tests are often specially designed for this purpose. The lowest frequency of operation of an RC is decided by its size. With a trend of lower frequency bands being allocated for mobile phones, the minimum size of RCs for mobile phone antenna tests increases, and is approaching the size of a normal room. At the same time, many large shielded rooms are already in use for various electrical measurements. In this paper, a standard shielded room designed for EMC testing is used as an RC for mobile phone antenna tests. To complete the RC, a large mode stirrer is built. The fact that the room is also used for other tests requires a detachable, foldable, and lightweight stirrer design. Therefore, metal meshes are evaluated for the design of the mode stirrer. The performance of the used room is verified by standard tests for RCs, and it is verified that it is possible to measure antennas from about 400 MHz up to 4 GHz with good accuracy. The size of the room also enables measurements including humans carrying mobile phones or body area networks.

NMR imaging of cell phone radiation absorption in brain tissue

A method is described for measuring absorbed electromagnetic energy radiated from cell phone antennae into ex vivo brain tissue. NMR images the 3D thermal dynamics inside ex vivo bovine brain tissue and equivalent gel under exposure to power and irradiation time-varying radio frequency (RF) fields. The absorbed RF energy in brain tissue converts into Joule heat and affects the nuclear magnetic shielding and the Larmor precession. The resultant temperature increase is measured by the resonance frequency shift of hydrogen protons in brain tissue. This proposed application of NMR thermometry offers sufficient spatial and temporal resolution to characterize the hot spots from absorbed cell phone radiation in aqueous media and biological tissues. Specific absorption rate measurements averaged over 1 mg and 10 s in the brain tissue cover the total absorption volume. Reference measurements with fiber optic temperature sensors confirm the accuracy of the NMR thermometry.

Antennas in Cellular Phones for Mobile Communications

The mobile industry has experienced a dramatic growth; it evolves from analog to digital 2G (GSM), then to high date rate cellular wireless communication such as 3G (WCDMA), and further to packet optimized 3.5G (HSPA) and 4G (LTE and LTE advanced) systems. Today, the main design challenges of mobile phone antenna are the requirements of small size, built-in structure, and multisystems in multibands, including all cellular 2G, 3G, 4G, and other noncellular radio-frequency (RF) bands, and moreover the need for a nice appearance and meeting all standards and requirements such as specific absorption rates (SARs), hearing aid compatibility (HAC), and over the air (OTA). This paper gives an overview of some important antenna designs and progress in mobile phones in the last 15 years, and presents the recent development on new antenna technology for LTE and compact multiple-input-multiple-output (MIMO) terminals.

Compact conventional phone antenna integrated with wideband multiple‐input‐multiple‐output antenna

AbstractA compact conventional phone antenna integrated with wideband multiple‐input‐multiple‐output (MIMO) antenna is presented.Within operation band of the MIMO antenna, the effect of mutual coupling between the conventional phone antenna and the MIMO antenna is reduced by etching three slits into the ground plane, and this slits also can relieve the impedance matching degradation caused by the mutual coupling between the conventional phone antenna and the MIMO antenna. A wideband T‐shaped neutralization line without effect on the performance of conventional phone antenna is applied to enhance the isolation for the two MIMO antenna elements. Therefore, high isolation is achieved within the operation band of the MIMO antenna. The two operation bands of the convention phone antenna with VSWR ≤ 3 are 0.89–0.96 GHz and 1.71–2.18 GHz, respectively, and the operation band of the MIMO antenna with VSWR ≤ 1.7 and isolation ≥ 20 dB is 2.4–3.7 GHz. Moreover, the conventional phone antenna has good omnidirectional radiation patterns in H‐plane, and the MIMO antenna has back‐radiation patterns for diversity gain. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1958–1962, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26930

A Compact Wideband MIMO Antenna With Two Novel Bent Slits

A compact wideband multiple-input- multiple-output (MIMO) antenna is presented. The MIMO antenna consists of two symmetric monopoles with edge-to-edge separation of nearly 0.083 λ0 at 2.5 GHz. Two novel bent slits are etched into the ground plane. At the lower frequencies, the bent slits can reduce the mutual coupling and have slight effect on the reflection coefficient. At the higher frequencies, the slits can be considered as slit antennas to widen the impedance bandwidth because the two slits are coupled fed by two 50-Ω microstrip lines, respectively. Two triangles are cut from the ground plane. In this way, the reflection coefficient and isolation of the two slit antennas can be improved. A bandwidth of 92.7% with |S11| ≤ -10 dB and |S21 | ≤ -18 dB from 2.4 to 6.55 GHz is achieved. In order to provide quantifications for the performance of the MIMO antenna in real-world usage conditions, the effects of human hand and head on the performance of the MIMO antenna are investigated. The results show that the MIMO antenna serving as a phone antenna can provide spatial and pattern diversity to combat multipath fading.

Editor's Comments

The design of modern, practical antennas for mobile phones typically involves satisfying requirements that go beyond the straightforward operating parameters of the antenna in free space. For example, such additional requirements can include the over-the-air performance of the mobile phone in the presence of the user's hand and head, meeting SAR (Specific Absorption Rate) standards, and meeting hearing-aid compatibility (HAC) requirements. In their feature article, X. L. Chen, E. Ofli, N. Chavannes, and N. Kuster describe the use of a commercial Finite-Difference Time-Domain (FDTD)-based electromagnetic simulation software package and the genetic algorithm to optimize the design of mobile-phone antennas to meet such disparate real-world requirements. The article begins with a description of the FDTD software's capabilities, and the use of a genetic algorithm in such software to optimize an antenna design across a range of parameters. The optimization was parallelized using two networked computers. How the optimization method was applied to the antenna is explained. The authors then describe the cell phone modeled in the study, as well as the models used for the three types of antennas considered: a folded-monopole antenna, a planar inverted-F antenna (PIFA), and a folded inverted conformal antenna (FICA). The way these antennas were parameterized and details of the optimization approach are then explained. The optimized results of the simulations included the free-space performance of the antennas in the cell phone, the performance of the antennas in the cell phone in the presence of hand and head phantoms, the SAR for the cell phone, and the hearing-aid compatibility results. In addition to discussing what factors affected the results obtained, the authors also provide information on the number of simulations and the computational time required to produce the results. The article provides quite realistic examples of practical optimization problems faced by designers of cell-phone antennas, while also providing interesting insight into the performance of the types of antennas studied in realistic cell-phone usage scenarios.

Two interlaboratory comparison programs on EMF measurements performed in Greece

This paper presents two interlaboratory comparison schemes on electromagnetic field measurements. The first scheme involves measurements of the electric field produced by a scale transmission line and of the magnetic field produced by a medium voltage cable, whereas the second scheme involves measurements of the high frequency electromagnetic fields level and calculation of the total exposure ratio in the vicinity of mobile phone base stations and antennas transmitting in the radio and TV frequency bands. The measurements procedure and the calculation of the performance statistics z scores are analyzed for both schemes. Emphasis is given to the evaluation of the results, in order to investigate possible improvements on the overall implementation of the schemes and error factors related to the equipment and the measurement procedures of the participants.

A DECISION-MAKING MODEL FOR SELECTING THE GSM MOBILE PHONE ANTENNA IN THE DESIGN PHASE TO INCREASE OVER ALL PERFORMANCE

The wireless link between a mobile phone and its surrounding crucially depends on the quality and properties of the mobile phone antenna. The process of antenna selection is a multi-criteria decision-making problem with con∞icting and diverse objectives. In this work, a model was built to select the best GSM mobile phone antenna in the design phase to increase the overall performance in the band. The model includes building an analytic hierarchy structure with a tree of hierarchical criteria and alternatives to ease the decision-making. The antenna options considered were limited to retractable whip antenna, loop chip antenna, monopole antenna, planar inverted F-antenna (PIFA), microstrip patch antenna, and printed slot antenna. An Analytical Hierarchy Process (AHP) was used to assist in building the model and help draw decisions. As a result of the decision making process, the monopole antenna was found to be the best choice for the GSM mobile phone antenna. Expert Choice TM software was used to conduct the experimental assessments. The judgments were found to be consistent, precise and justiflable with narrow marginal inconsistency values. The paper also presents a thorough sensitivity analysis to demonstrate the confldence in the drawn conclusions.

LTE를 포함한 전 휴대폰 서비스 대역 하이브리드 안테나

In this paper, we designed and implemented a Monopole+IFA(Inverted F Antenna) hybrid antenna using the coupled feeding structure for the all band mobile phone. Studied antenna has wide band characteristics by the simultaneous operation both monopole and IFA under the coupled feeding structure. An antenna has designed PCB embedded type without antenna carrier component for the low in cost. Implemented antenna has within 2.5:1 for VSWR under LTE/CDMA/GSM900/DCS/USPCS/WCDMA/WiBro/WiFi in all band for the mobile services Measured average gains and efficiencies were -3.98~-0.09 dBi and 40.03~97.99 % for the LTE, CDMA, GSM900 band, and -3.90~-1.01 dBi and 40.70~79.31 % for the DCS, USPCS, WCDMA, WiBro, WiFi band. It`s shown that studied antenna can be applied to all band mobile phone antenna including LTE.

Internal mobile phone antenna array for LTE/WWAN and LTE MIMO operations

AbstractAn antenna array comprising a main antenna for eight‐band LTE/WWAN operation and an auxiliary antenna to combine with the main antenna for LTE MIMO operation in the mobile phone is presented. Both the main and auxiliary antennas are disposed at the bottom edge of the system circuit board of the mobile phone and separated by a protruded ground. The main and auxiliary antennas can respectively fit in two small no‐ground regions of 15 × 30 mm2 and 15 × 20 mm2 on the system circuit board, while the protruded ground in‐between the two antennas has a width of 10 mm for mounting a USB data port. The main antenna covers the 704–960/1710–2690 MHz bands for eight‐band LTE/WWAN operation, and the auxiliary antenna covers the 704–787/2300–2690 MHz bands such that the main and auxiliary antennas together can perform LTE MIMO operation in the LTE700/2300/2500 bands. The proposed antenna array is fabricated and tested. Results are presented and discussed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26038

Brain Glucose Metabolism Raised Near Cell Phone's Antenna

Brain Glucose Metabolism Raised Near Cell Phone's Antenna

Planar strip monopole with a chip‐capacitor‐loaded loop radiating feed for LTE/WWAN slim mobile phone application

AbstractA small‐size wideband internal mobile phone antenna formed by a planar strip monopole with a chip‐capacitor‐loaded loop radiating feed for achieving eight‐band long term evolution/wireless wide area network operation in the 698–960 and 1710–2690 MHz bands is presented. The antenna is suitable to be disposed on a small no‐ground board space (15 × 45 mm2) of the system circuit board and enclosed by an L‐shaped system ground plane of the mobile phone. On the protruded ground of the L‐shaped system ground plane, a universal series bus connector for the data port of the mobile phone can be accommodated without affecting the antenna performances. The antenna also shows a low profile of 3 mm above the circuit board, which makes it very promising for slim mobile phone applications. The proposed antenna was fabricated and tested. Measured and simulated results are presented. The specific absorption rate results of the antenna are also analyzed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:952–958, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25845

Using a choice experiment to estimate the benefits of a reduction of externalities in urban areas with special focus on electrosmog

Traffic noise, air pollution and electromagnetic pollution (i.e. nonionizing radiation, also called electrosmog) are typical negative local externalities in urban areas. They are side effects of human and economic activities (e.g. road transport, telecommunication) and they affect individuals’ well being negatively without compensation. In recent years, the increased number of mobile phone antennas in residential areas, and thus the increased intensity of radiated power, has aroused public concern, discussions and protests. The view of an antenna is annoying an increasing number of inhabitants. In this article, the stated Choice Experiment (CE) is used to estimate the Willingness To Pay (WTP) residents in the cities of Zurich and Lugano place on the reduction of these three environmental loads. Estimation results reveal that there is a positive and significant WTP for a reduction of air pollution and traffic noise levels to those limit values fixed by the government. Respondents also show WTP for reducing electrosmog and removing mobile phone antennas from their view, however to a lesser extent. In addition, this is the first study that estimates the benefit of a reduction of electrosmog using a CE.

A Compact Dual-Band Mimo Antenna of Mobile Phone

A compact dual-band multiple-input-multiple-output (MIMO) antenna is presented. The MIMO antenna consists of two orthogonal elements with edge-to-edge separation of nearly 0.047λ0 at 2.0 GHz, and the element is two-strip structure which can help to improve the impedance matching and isolation. Result shows a dual-band of 76% from 1.62 to 3.6 GHz and 28.5% from 4.44 to 5.92 GHz. The MIMO antenna has strong robust property to the nearby conducting elements, and that is an advantage over the conventional MIMO antennas. The mean effective gain (MEG), radiation efficiency, correlation coefficient, and effective diversity gain (EDG) are calculated to evaluate the diversity performance of the MIMO antenna. To provide quantifications for the performance of the MIMO antenna in real-world usage condition, effects of human hand and head on radiation efficiency and total radiated power (TRP) are investigated. The results indicate the antenna serving as a phone antenna can provide spatial and pattern diversity to combat multipath fading.

Analysis of Mobile Phone Antenna Performance within the Head and Hand Phantoms

This paper proposes the effect of the hand-hold position on the electromagnetic (EM) wave interaction of a candy bar type and clamshell type cellular handset and a human head and hand is investigated. The human hand influences the performance of terminal antennas, and it is the main cause for absorption and detuning. In spite of its importance in mobile-phone design and validation processes, it is still complicated to take it into account because a lack of knowledge in the area. In this paper, a rigorous investigation methodology is described for the study of candy bar, and clam shell mobile phone CAD model is used to numerically investigate the effect of hand phantom of mobile phone antenna radiation performance. The simulation results show that mobile phone grip styles of the hand phantom material properties, wrist and length, and hand phantom sizes and different positions is the important parameter to antenna performance. The grip style has direct implications in the definition of phantom head. The preference of the handset with respect to the side of the user’s head depends on the mobile phone form factor and size. The results established high reliability and suitability for providing decision rationale for the design of complex high-end multi-band mobile phones.

Radiation efficiency improvement for dual-mode mobile phone using a slot on a ground plane

A dual-band mobile phone antenna with dual feeders is proposed to improve antenna radiation efficiency in the CDMA band of 824–894 MHz and the GSM band of 880–960 MHz. The proposed antenna consists of two planar inverted-F antennas and a common ground plane with a slot. The electric fields are more confined on each radiating element region at each band in this configuration. Measured results show that radiation efficiencies of the proposed antenna are improved by up to 20% compared to those of the antenna without a slot.

MEASUREMENT METHOD FOR SENSITIVITY ANALYSIS OF PROXIMITY SENSOR AND SENSOR ANTENNA INTEGRATION IN A HANDHELD DEVICE

A method for measuring the sensitivity of a capacitive proximity sensor and an application using the sensor as a proximity detector in mobile phone antennas is presented. 2D sensor data plots were physically more exact for tuning sensor placement. 3D sensor data plots were suitable for sensor intensity comparison, highlighting sensor difierences in multiple sensor applications and efiects in sensor's output due to shadowing mechanical objects. The antenna proximity sensor was measured and optimised with sensitivity measurements. In a PIFA application the antenna load could be detected from both sides and from above the antenna on a scale of 4:03 ¢ 10 i14 F to 4:33 ¢ 10 i14 F. The cases present all possible positions of holding a phone used in either the \calling or \browsing mode. The method and the application emphasise the physical sensitivity and electrical flelds of the sensor. The characteristics can be further improved by using other sensor types, sensor data fusion and advanced imitation of multisensory spatial interaction by humans and animals.

MEMS Packaging with 3D-MID Technology

3D-MID (three dimensional molded interconnect devices) technology (which is already broadly used for 3D-MID mobile phone antennas) is also used for MEMS packaging and sensors applications. 3D-MID allows miniaturization by the integration of mechanical and electronic functions in one part. The 3D electronic circuit is integrated into a 3D plastic casing or carrier, making it possible to achieve much more compact construction and much greater function density. More and more applications involving electrical and electro-optical circuits are made using 3D-MID technology. Typical 3D-MID applications are: Sensor packaging, LED packaging, security casings, RFIDs and Antennas. The main areas of application are in the automotive, medical, industrial technology and telecommunications sectors.

Improvement of radiation performance of mobile phone antenna using parasitic element

In this paper, we propose a method of using a parasitic element to improve the radio frequency performance of PIFA (Planar Inverted F Antenna) which is built in mobile phone for EGSM, DCS, PCS, and WCDMA bands. The proposed methodology based on external parasitic element in the handset case is validated for extremely thin mobile phone model, which has limited space for any additional parasitic element inside antenna design space. The proposed parasitic element exhibits TRP (Total Radiated Power) and TIS (Total Isotropic Sensitivity) improvement of 0.4 dB to1.1 dB and 0.2 dB to 0.6 dB, respectively, under the free space measurement condition, while 0.6 dB to 0.7 dB and 0.4 dB to 1.1 dB for the hand phantom environment.

Small-size 11-band LTE/WWAN/WLAN internal mobile phone antenna

This work presents an internal mobile phone antenna occupying a small board space of 600 mm2 on the system circuit board and providing three wide operating bands of at least 698–960, 1710–2690, and 5150–5825 MHz for the 11-band long term evolution (LTE)/ wireless wide area network (WWAN)/wideband local area network (WLAN) operation.This includes three LTE bands of LTE700/2300/2500, five WWAN bands of GSM850/900/1800/1900/UMTS, and three WLAN 2.4/5.2/5.8 GHz bands. The antenna is a coupled-fed shorted monopole, with a wide feeding strip in the coupling feed, a long shorting strip closely coupled to the shorted monopole, and a tuning stub connected to the shorting strip. The antenna's three wide operating bands are achieved and controlled by tuning the width of the feeding strip, the gap between the shorting strip and the shorted monopole, and the dimensions of the tuning stub. Operating principle of the proposed antenna is described in detail in this article. Results of the fabricated antenna are presented and discussed. The specific absorption rate results of the antenna with the presence of the user's head and hand are also studied. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2603–2608, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25526