Balanced antennas for mobile handset applications. Simulation and Measurement of Balanced Antennas for Mobile Handsets, investigating Specific Absorption Rate when operated near the human body, and a Coplanar Waveguide alternative to the Balanced Feed.

The main objectives of this research are to investigate and design low profile antennas for mobile handsets applications using the balanced concept. These antennas are considered to cover a wide range of wireless standards such as: DCS (1710¿1880 MHz), PCS (1850¿1990 MHz), UMTS (1920¿2170 MHz), WLAN (2400¿2500 MHz and 5000 ¿ 5800 MHz) and UWB frequency bands. Various antennas are implemented based on built-in planar dipole with a folded arm structure. The performance of several designed antennas in terms of input return loss, radiation patterns, radiation efficiency and power gain are presented and several remarkable results are obtained. The measurements confirm the theoretical design concept and show reasonable agreement with computations. The stability performance of the proposed antenna is also evaluated by analysing the current distribution on the mobile phone ground plane. The specific absorption rate (SAR) performance of the antenna is also studied experimentally by measuring antenna near field exposure. The measurement results are correlated with the calculated ones. A new dual-band balanced antenna using coplanar waveguide structure is also proposed, discussed and tested; this is intended to eliminate the balanced feed network. The predicted and measured results show good agreement, confirming good impedance bandwidth characteristics and excellent dual-band performance. In addition, a hybrid method to model the human body interaction with a dual band balanced antenna structure covering the 2.4 GHz and 5.2 GHz bands is presented. Results for several test cases of antenna locations on the body are presented and discussed. The near and far fields were incorporated to provide a full understanding of the impact on human tissue. The cumulative distribution function of the radiation efficiency and absorbed power are also evaluated.UK Engineering and Physical Sciences Research Council (EPSRC

Interaction Between Electromagnetic Field and Human Body for Dual Band Balanced Antenna Using Hybrid Computational Method

yesThis paper describes a hybrid computational method which efficiently models the interaction between a small antenna placed in proximity with the human body. Results for several test cases of placed in different locations on the body are presented and discussed. The near and far fields were incorporated into the study to provide a full understanding of the impact on human tissue. The cumulative distribution function of the radiation efficiency and absorbed power is also provided. The antennas are assumed to be operating over the 2.4 GHz and 5.2 GHz WLAN frequencies

Frequency Tuned Planar Inverted F Antenna with L Shaped Slit Design for Wide Frequency Range.

yesA frequency tuned antenna has been designed to meet the coverage requirements of the DCS, PCS, UMTS and WLAN bands. The antenna consists of a main patch, and a planar inverted L (PIL) slot. The radiator patch is fed, and shorted, using simple feed lines with broadband characteristics. The handset represents the finite ground plane, and a varactor diode is mounted across the middle of the slot for tuning purposes. Initial tuning was obtained by placing lumped capacitors, instead of the varactor, over the radiator. Good agreement is obtained between the predicted and measured input return loss, gain and radiation pattern over the tuned frequency range.MSCR

Compact wideband balanced antenna for mobile handsets

A novel miniature balanced mobile handset antenna is presented in this study, which covers digital communication system (DCS) (1710-1880 MHz), personal communication system (PCS) (1850-1990 MHz), universal mobile telecommunications system (UMTS) (1920-2170 MHz) and wireless local area network (WLAN) (2400-2484 MHz) frequency bands. The antenna is a built-in planar dipole with folded structure and with the addition of a dual arm on each half of the dipole. The performance of the antenna is analysed and optimised under certain design constraints. The stability performance of the proposed antenna against proximity effects is evaluated. The effects of the phone user's hand on the return loss and radiation patterns have been characterised by simulation with a simple hand model. A prototype of the proposed antenna is fabricated and tested. A wide bandwidth planar balun is used to feed the wideband balanced antenna from an unbalanced source. The calculated and measured results show good agreement and confirm good wideband characteristics with multiband operation. The specific absorption rate (SAR) performance of the antenna is also studied experimentally by measuring near field exposure. The measured results have shown low induced current in the ground plane and thus confirm minimisation of performance variations and SAR

Compact Dual-band Balanced Handset Antenna for WLAN Application

In this paper, a balanced antenna for mobile handset applications with dual-frequency performance, covering the 2.4 GHz and the entire 5 GHz WLAN frequency bands, is investigated and discussed. The antenna is a thin-strip planar dipole with folded structure and a dual-arm on each monopole. For validation, the antenna prototype was fabricated and tested. The performance of this balanced antenna was verified and characterised in terms of the antenna return loss, radiation pattern, power gain and surface current distribution of the proposed antenna. The predicted and measured results show good agreement

Low profile dual-band-balanced handset antenna with dual-arm structure for WLAN application

In this study, a low profile and dual-band-balanced antenna for mobile handset applications, covering the 2.4 and 5 GHz WLAN frequency bands, is investigated and discussed. The antenna is a thin-strip planar dipole, with folded structure, and a dual-arm on each half of the dipole. The performance of the proposed antenna has been analysed and optimised for the two targeted frequency bands. For validation purposes, an antenna prototype was fabricated and tested. The prototype performance is characterised in terms of the antenna reflection coefficient, radiation pattern, power gain and surface current distribution. The predicted and measured results show relatively good agreement, and confirm good impedance bandwidth characteristics and excellent dual-band performance. In addition, the antenna radiation performance is investigated when the antenna is placed in several locations on the human body, using a hybrid computational electromagnetics technique

Multi-band weakly ground-coupled balanced antenna design for portable devices

A balanced antenna for wireless portable devices applications with multiple band operational performance is investigated and discussed. The designed antenna is weakly ground-couple, although can be considered as an energy-efficient radiator. The antenna structure is a thin-strip planar dipole with a dual-folded structure on each arm. The performance of the proposed antenna is analysed and optimised for WLAN and WiMAX applications over the relevant frequency bands, including the 2.4 and 5.2 GHz WLAN bands and the 2.5 and 3.5 WiMAX bands. For validation, the antenna prototype was fabricated and tested. The performance of this balanced antenna was verified and characterised in terms of the return loss, radiation pattern and power gain. The predicted and measured results show acceptable agreement and the results also confirm good impedance bandwidth characteristics with excellent dual-band operation