Abdullah Al-Hadi Azremi

Multiband Fractal Planar Inverted F Antenna (F-PIFA) for Mobile Phone Application

The design of a novel Fractal planar inverted F antenna (F-PIFA) based on the self affinity property is presented in this paper. The procedure for designing a Fractal Planar Inverted F Antenna is explained and three different iterations are designed for use in cellular phones. The F-PIFA has a total dimension of 27 mm × 27 mm and has been optimized to be operational at GSM (Global System for Mobile Communication), UMTS (Universal Mobile Telecommunication System) and HiperLAN (High Performance Radio LAN) with the frequencies range from 1900 MHz to 2100 MHz, 1885 to 2200 MHz and 4800 MHz to 5800 MHz respectively. The antenna achieved −6 dB return loss at the required GSM, UMTS and HiperLan frequencies with and has almost omnidirectional radiation pattern. This antenna has been tested using realistic mobile phone model and has met the performance criteria for a mobile phone application. Simple semi-empirical formulas of the operational frequency, numerical calculation and computational SAR of the antenna also has been presented and discussed.

Five-element inverted-F antenna array for MIMO communications and radio direction finding on mobile terminal

A five-element inverted-F antenna array on mobile terminal for both multiple input multiple output (MIMO) communications and radio direction finding (RDF) applications is presented. The multi-element antenna (MEA) system has been designed to be used in the frequency band of the future Long Term Evolution (LTE) system at 3400–3600 MHz and integrated along the edges of the upper ground plane of a clamshell type mobile terminal. Without using any specific multi-antenna isolation techniques, the antennas have been optimized to have acceptable mutual coupling and small envelope correlation in order to provide enhanced capacity with multiple input multiple output (MIMO) techniques. The ambiguities of the proposed design in RDF applications have also been investigated. A prototype has been fabricated and tested. Good agreement between numerical simulations and experimental results has validated the antenna concept.

Reflection loss performance of hexagonal base pyramid microwave absorber using different agricultural waste material

Hexagonal base pyramid microwave absorber is the new design of microwave absorber. In this work, two sub-shapes are considered to compare it reflection loss performance. The shapes are hexagonal and truncated hexagonal base pyramid. Three sample of agricultural waste are used that is rice husk, rice straw and banana leaves. Before that, free space measurement technique is applied to define the dielectric constant and tangent loss of the material used. These microwave absorbers have been designed to operate effectively between the frequencies of 1 GHz and 20 GHz.

Performance analysis of broadband coupling - element - based multiantenna structure for mobile terminal with hand effects

This paper presents a comprehensive simulation study on the performance of broadband coupling-element-based multiantenna structures on a mobile terminal at the 2000 MHz Universal Mobile Telecommunications System (UMTS) frequency band with varying two significant hand effects; vertical position of hand along terminal chassis, and distance between hand palm and terminal chassis. The results reveal that there exists an MEG imbalance between antenna elements due to hand effects and it is shown that an MEG imbalance of 3.7 dB lead to a reduction of 1.9 dB in diversity gain at 99% reliability level using maximal ratio combining (MRC) technique. For a two-element antenna configuration, the impact of MEG imbalance on diversity gain is more significant when only one antenna element is in close proximity to the hand, compared to when both antenna elements are in the presence of the hand. It is also shown that a broadband multiantenna structure with elements vertically oriented along the edges of a small 100 mm x 40 mm mobile terminal chassis achieves better performance in port-to-port isolation, MEG imbalance and diversity gain compared to other studied multiantenna configurations when the users hand is present.

DESIGN AND MEASUREMENT-BASED EVALUATION OF MULTI-ANTENNA MOBILE TERMINALS FOR LTE 3500 MHz BAND

Design of multi-element antennas for small mobile terminals operating at higher frequencies remains challenging despite smaller antenna dimension and possibility of achieving electrically large separation between them. In this paper, the importance of the type of radiating elements operating at 3400-3600 MHz and their locations on the terminal chassis are highlighted. An isotropic radiation pattern that receives incoming signals from arbitrary directions is obtained by combining the radiation patterns of multiple antennas with localized chassis current distribution. Four multiport antennas configurations with two- and eight-element antennas are designed and evaluated experimentally in indoor propagation environments. Our proposed designs of multi-element antennas provide the highest MIMO channel capacity compared to their counterparts using antennas with less localized chassis current distribution, even in the presence of users hand.

Measurement-Based Evaluation of Link Budget Gain from 3GPP LTE Uplink Transmit Antenna Selection

This paper presents a measurement-based evaluation of link budget gain from uplink transmit antenna selection in 3GPP LTE. In contrast to earlier studies, the results are based on channel measurements and realistic non-omnidirectional mobile terminal antennas. Further, in addition to the impact of fast selection based on small-scale fading power, also the gain from slow selection based on average signal power is evaluated. In the evaluated measurement cases, fast and slow fading based transmit antenna selection result in up to

Isolation improvement method for mobile terminal antennas at lower UHF band

3.7

On diversity performance of two-element coupling element based antenna structure for mobile terminal

and

Coupling Element-Based Dual-Antenna Structures for Mobile Terminal with Hand Effects

3.2

Study on the minimum required size of the low-band cellular antenna in variable-sized mobile terminals

dB average power gain, respectively, with respect to the fixed uplink transmit antenna case. This implies that with practical non-omnidirectional terminal antennas a major portion of the gain can be realized based on slow selection, hence justifying a simple open-loop transmit antenna selection scheme which is also applicable to FDD systems.