Outi Kivekäs

Mobile Terminal Antenna Performance With the User's Hand: Effect of Antenna Dimensioning and Location

This letter reports a systematic simulation study of the performance of mobile terminal antennas in the vicinity of the users hand. The effects of antenna dimensioning and antenna location on the ground plane of the device are demonstrated. The studied performance parameters are quality factor, radiation efficiency, and frequency detuning. Based on the results, beneficial approaches and general guidelines for antenna designs with a reduced effect of the users hand can be given. For instance, it is shown that the radiation efficiency with the users hand stays nearly constant (variation <;0.2 dB) despite the changes in the antenna element height (2-6.6 mm at 900 and 2000 MHz).

Broadband Equivalent Circuit Model for Capacitive Coupling Element–Based Mobile Terminal Antenna

In this letter, it is shown how the behavior of a capacitive coupling element (CCE)-based mobile terminal antenna can be modeled at the UHF band as a combination of the separate wavemodes of the structure. The proposed equivalent circuit model improves the general understanding of the operation of the antenna structure. It can be used for analyzing the combined performance of the capacitive coupling element and terminal chassis, but it also helps in analyzing how different parts of the antenna structure contribute to the impedance and radiation.

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

This paper presents a comprehensive simulation study on the performance of coupling element-based dual-antenna structures on a mobile terminal at the 2,000xa0MHz 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 in uniformly distributed isotropic environment, there exists a gain imbalance between antenna elements due to hand effects and it is shown that a gain imbalance of 3.7xa0dB lead to a reduction of 1.9xa0dB in diversity gain at 99% reliability level using maximal ratio combining (MRC) technique. For a dual-antenna configuration, the impact of gain 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 dual-antenna structure with elements vertically oriented along the edges of a small 100xa0mmxa0×xa040xa0mm mobile terminal chassis achieves better performance in port-to-port isolation, gain imbalance and diversity gain compared to other studied dual-antenna configurations when the user’s hand is present.

Equivalent circuit model-based approach on the user body effect of a mobile terminal antenna

The user body effect on the operation of mobile terminal antennas is investigated based on equivalent circuit modelling. The purpose is to increase the understanding of the phenomenon, which is important, for example, when designing mobile terminal antennas with minimised user effect.

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.