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Pertti Vainikainen - One of the best experts on this subject based on the ideXlab platform.

  • inherently non resonant multi band mobile Terminal Antenna
    Electronics Letters, 2013
    Co-Authors: Risto Valkonen, Janne Ilvonen, Clemens Icheln, Pertti Vainikainen
    Abstract:

    An inherently non-resonant capacitive coupling element Antenna for mobile handsets is presented. The compact Antenna includes a simple coupling element with a novel multi-band matching circuit for simultaneous 698-960 and 1710-2690 MHz operation. Experimental results show that the Antenna performs strongly in comparison to the current state-of-the-art in mobile Terminal Antennas, and that the non-resonant Antenna is a competitive choice for mobile Terminals.

  • Reducing the interaction between user and mobile Terminal Antenna based on Antenna shielding
    2012 6th European Conference on Antennas and Propagation (EUCAP), 2012
    Co-Authors: Janne Ilvonen, Jari Holopainen, Olli Kivekäs, Risto Valkonen, Pertti Vainikainen
    Abstract:

    Reducing the effect of the hand and the head of a user on the operation of mobile Terminal Antennas is investigated with simulations and measurements. The study is made at 900 and 2000 MHz. The shielded Antenna structure consists of two Antenna elements. Non-self-resonant Antenna elements are required to obtain an improved Antenna performance. Depending on the use position, the better-performing Antenna element is selected and the other is acting as a shield. It is shown that the proposed structure can improve the total efficiency with hand and head by 5.0 dB and decrease the maximum specific absorption rate (SAR) in the head by 81% at 900 MHz compared to the traditional single element structure. At 2000 MHz, the benefits are 2.1 dB and 43%, respectively. The shielding structure can be used also to significantly decrease the SAR in the hand.

  • Avoiding the interaction between hand and capacitive coupling element based mobile Terminal Antenna
    Proceedings of the 5th European Conference on Antennas and Propagation (EUCAP), 2011
    Co-Authors: Risto Valkonen, Jari Holopainen, Janne Ilvonen, Clemens Icheln, Kimmo Rasilainen, Pertti Vainikainen
    Abstract:

    Interaction between a mobile Terminal Antenna and a hand of a user is investigated with an experimental study using capacitive coupling element Antennas and homogeneous anthropomorphically shaped hand phantoms. The frequency bands used in the study are 880-960 MHz and 1710-1880 MHz. The significance of the shape, size and position of the Antenna element on the Antenna input impedance and efficiency in the presence of a hand phantom is demonstrated. The results indicate that a part of the hand-originated losses can be avoided by taking the hand effects into consideration in Antenna design.

  • Antenna shielding method reducing interaction between user and mobile Terminal Antenna
    Electronics Letters, 2011
    Co-Authors: Janne Ilvonen, Olli Kivekäs, Risto Valkonen, P. Li, Pertti Vainikainen
    Abstract:

    A new method to decrease the effect of the hand and head on the operation of mobile Terminal Antennas at the 900 MHz frequency band is introduced. The proposed structure consists of two Antenna elements. Depending on the use position, the better-performing Antenna element is selected and the other is acting as a shield. It is shown by simulations that the proposed structure can improve the total efficiency with the hand by up to 4.8 dB and decrease the maximum specific absorption rate in the head by 30-44% compared to the traditional single element structure.

  • broadband equivalent circuit model for capacitive coupling element based mobile Terminal Antenna
    IEEE Antennas and Wireless Propagation Letters, 2010
    Co-Authors: Jari Holopainen, Olli Kivekäs, Risto Valkonen, Janne Ilvonen, Pertti Vainikainen
    Abstract:

    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.

Junwei Lu - One of the best experts on this subject based on the ideXlab platform.

  • Smart Mobile Terminal Antennas for Wireless Communications and Computing
    2017
    Co-Authors: Junwei Lu, David Ireland
    Abstract:

    The paper presents an electronically beam switched smart mobile Terminal Antenna (SMTA) array with three different configurations. The SMTA array can be used in wireless communications and computing systems. The radiation beam pattern toward desired direction can be controlled by switched beam control algorithm. Four different structures of SMTA arrays and their design considerations are discussed in this paper.

  • Optimised wireless network using smart mobile Terminal Antenna (SMTA) system
    2010 Asia-Pacific International Symposium on Electromagnetic Compatibility, 2010
    Co-Authors: Junwei Lu, Ian Scriven, Wayne Water
    Abstract:

    This paper presents a complete novel smart mobile Terminal Antenna system (SMTA) for optimising wireless network and security performance. This SMTA system uses a switched radiation beam approach in an attempt to achieve optimal wireless network performance while increasing network security for indoor and outdoor applications, and signal tracking for marine application. Test results are presented that demonstrate the ability of the SMTA system to maintain consistently high wireless signal levels in a dynamic and noisy environment.

  • multi objective optimization in high frequency electromagnetics an effective technique for smart mobile Terminal Antenna smta design
    IEEE Conference on Electromagnetic Field Computation, 2009
    Co-Authors: Junwei Lu, David Ireland, Andrew Lewis
    Abstract:

    This paper describes several major optimization techniques, such as FDTD-simulated annealing (SA), FEM-Genetic algorithms (GA), and FD-TD-particle swarm optimization (PSO) and frequency domain FEM-PSO used for high-frequency electromagnetics and their applications in smart mobile Terminal Antenna (SMTA) design. Two SMTAs, a dielectric embedded electronically switched multi-beam (DE-ESMB) Antenna and a dielectric embedded electronically steerable passive array radiator (DE-ESPAR) Antenna, were successfully developed by using these multi-objective optimization techniques. The design considerations and rules based on computational electromagnetics and optimization techniques are explored for the practical application of dielectric embedded SMTAs.

  • Multi-Objective Optimization in High Frequency Electromagnetics—An Effective Technique for Smart Mobile Terminal Antenna (SMTA) Design
    IEEE Transactions on Magnetics, 2009
    Co-Authors: Junwei Lu, David Ireland, Andrew Lewis
    Abstract:

    This paper describes several major optimization techniques, such as FDTD-simulated annealing (SA), FEM-Genetic algorithms (GA), and FD-TD-particle swarm optimization (PSO) and frequency domain FEM-PSO used for high-frequency electromagnetics and their applications in smart mobile Terminal Antenna (SMTA) design. Two SMTAs, a dielectric embedded electronically switched multi-beam (DE-ESMB) Antenna and a dielectric embedded electronically steerable passive array radiator (DE-ESPAR) Antenna, were successfully developed by using these multi-objective optimization techniques. The design considerations and rules based on computational electromagnetics and optimization techniques are explored for the practical application of dielectric embedded SMTAs.

  • Using Smart Mobile Terminal Antennas to Achieve Optimal Wireless Network Performance and Security
    2007 International Symposium on Electromagnetic Compatibility, 2007
    Co-Authors: Ian Scriven, Junwei Lu, David John Ireland
    Abstract:

    In this paper, a complete smart mobile Terminal Antenna system (SMTA) is presented. This system uses a radiation beam switching approach in an attempt to achieve optimal wireless network performance while increasing network security. Test results are presented that demonstrate the ability of the SMTA system to maintain consistently high wireless signal levels in a dynamic, noisy environment.

Shuji Kubota - One of the best experts on this subject based on the ideXlab platform.

  • Compact and low-profile MIMO Terminal Antenna employing bidirectional Yagi-Uda array
    2nd European Conference on Antennas and Propagation (EuCAP 2007), 2020
    Co-Authors: Naoki Honma, Kentaro Nishimori, Yasushi Takatori, Atsushi Ohta, Shuji Kubota
    Abstract:

    This paper proposes a compact and low-profile multi-input multi-output (MIMO) Terminal Antenna employing the bidirectional Yagi-Uda array. The parasitic Antennas that function as a director are designed to maximize the MIMO channel capacity. A parasitic Antenna optimization method, in which a 'parasitic channel' is defined, is also proposed. This method is effective in finding the optimum design with a very low computational load. Based on numerical analysis of an indoor environment, the proposed and optimally designed Antenna enhances the channel capacity by more than 10% compared to an Antenna without parasitic elements even when the space for the Antennas is limited such as in a PC card Terminal. (6 pages)

  • Proposal of compact MIMO Terminal Antenna employing Yagi-Uda array with common director elements
    2007 IEEE Antennas and Propagation Society International Symposium, 2007
    Co-Authors: Naoki Honma, Kentaro Nishimori, Yasushi Takatori, Atsushi Ohta, Shuji Kubota
    Abstract:

    In this paper, a compact MIMO Terminal Antenna employing Yagi-Uda arrays with common director elements is proposed. The Yagi-Uda array provides a high gain in the horizontal direction even when the array is arranged horizontally. The size of the proposed Antenna is fairly small because the director elements are shared between two Yagi-Uda arrays that face each other and the length of the array is approximately half of two individual Yagi-Uda arrays.

  • Compact and Low-Profile MIMO Terminal Antenna Employing Bidirectional Yagi-Uda Array
    Antennas and Propagation, 2007. EuCAP 2007. The Second European Conference on, 2007
    Co-Authors: Naoki Honma, Kentaro Nishimori, Yasushi Takatori, Atsushi Ohta, Shuji Kubota
    Abstract:

    This paper proposes a compact and low-profile multi-input multi-output (MIMO) Terminal Antenna employing the bidirectional Yagi-Uda array. The parasitic Antennas that function as a director are designed to maximize the MIMO channel capacity. A parasitic Antenna optimization method, in which a 'parasitic channel' is defined, is also proposed. This method is effective in finding the optimum design with a very low computational load. Based on numerical analysis of an indoor environment, the proposed and optimally designed Antenna enhances the channel capacity by more than 10% compared to an Antenna without parasitic elements even when the space for the Antennas is limited such as in a PC card Terminal.

Risto Valkonen - One of the best experts on this subject based on the ideXlab platform.

  • A varactor-based tunable matching network for a non-resonant mobile Terminal Antenna
    The 8th European Conference on Antennas and Propagation (EuCAP 2014), 2014
    Co-Authors: Yi Chen, Risto Valkonen, Robert Martens, Dirk Manteuffel
    Abstract:

    In this paper, we present a varactor-based tunable matching network for a mobile Terminal Antenna based on a non-resonant capacitive coupling element. The system is able to enhance the power transfer to the Antenna in the commonly used mobile communication bands within the frequency range 0.69 ≤ f [GHz] ≤ 3.6. The impedance of a mobile Terminal Antenna is dependent on the operating frequency and on the effects of the user interaction (e.g. hand and head proximity). This mismatched impedance can be correctly tuned using the proposed tunable matching network. In almost all of the typical usage scenarios, the transducer gain with the threshold value GT = -1.25 dB can be achieved. The average value of the total efficiency of the fabricated mock-up-system in free space within the conventional bands is η = 68%. The good radiation performance with user interaction is also shown in this paper using the proposed matching network.

  • effect of ground plane bending on mobile Terminal Antenna performance
    European Conference on Antennas and Propagation, 2013
    Co-Authors: Kimmo Rasilainen, Jari Holopainen, Risto Valkonen, Janne Ilvonen, Antti V Raisanen
    Abstract:

    The performance of mobile Terminal Antennas in the case of a non-planar ground plane is studied. The effects of bending are analysed using computer simulations and a resonator-based equivalent circuit model for improving the understanding of the phenomenon. Results show that bending the ground plane can have a considerable effect on the operation and performance of the Antenna. Resistive and reactive changes caused by the bending are accurately modelled with the equivalent circuit, and they can also be used to interpret changes in the quality factor.

  • inherently non resonant multi band mobile Terminal Antenna
    Electronics Letters, 2013
    Co-Authors: Risto Valkonen, Janne Ilvonen, Clemens Icheln, Pertti Vainikainen
    Abstract:

    An inherently non-resonant capacitive coupling element Antenna for mobile handsets is presented. The compact Antenna includes a simple coupling element with a novel multi-band matching circuit for simultaneous 698-960 and 1710-2690 MHz operation. Experimental results show that the Antenna performs strongly in comparison to the current state-of-the-art in mobile Terminal Antennas, and that the non-resonant Antenna is a competitive choice for mobile Terminals.

  • Reducing the interaction between user and mobile Terminal Antenna based on Antenna shielding
    2012 6th European Conference on Antennas and Propagation (EUCAP), 2012
    Co-Authors: Janne Ilvonen, Jari Holopainen, Olli Kivekäs, Risto Valkonen, Pertti Vainikainen
    Abstract:

    Reducing the effect of the hand and the head of a user on the operation of mobile Terminal Antennas is investigated with simulations and measurements. The study is made at 900 and 2000 MHz. The shielded Antenna structure consists of two Antenna elements. Non-self-resonant Antenna elements are required to obtain an improved Antenna performance. Depending on the use position, the better-performing Antenna element is selected and the other is acting as a shield. It is shown that the proposed structure can improve the total efficiency with hand and head by 5.0 dB and decrease the maximum specific absorption rate (SAR) in the head by 81% at 900 MHz compared to the traditional single element structure. At 2000 MHz, the benefits are 2.1 dB and 43%, respectively. The shielding structure can be used also to significantly decrease the SAR in the hand.

  • Avoiding the interaction between hand and capacitive coupling element based mobile Terminal Antenna
    Proceedings of the 5th European Conference on Antennas and Propagation (EUCAP), 2011
    Co-Authors: Risto Valkonen, Jari Holopainen, Janne Ilvonen, Clemens Icheln, Kimmo Rasilainen, Pertti Vainikainen
    Abstract:

    Interaction between a mobile Terminal Antenna and a hand of a user is investigated with an experimental study using capacitive coupling element Antennas and homogeneous anthropomorphically shaped hand phantoms. The frequency bands used in the study are 880-960 MHz and 1710-1880 MHz. The significance of the shape, size and position of the Antenna element on the Antenna input impedance and efficiency in the presence of a hand phantom is demonstrated. The results indicate that a part of the hand-originated losses can be avoided by taking the hand effects into consideration in Antenna design.

Gert Frølund Pedersen - One of the best experts on this subject based on the ideXlab platform.

  • Effect of Dielectric Properties of Human Hand Tissue on Mobile Terminal Antenna Performance
    2020 14th European Conference on Antennas and Propagation (EuCAP), 2020
    Co-Authors: Stanislav Stefanov Zhekov, Gert Frølund Pedersen
    Abstract:

    A good approach when designing Antennas for mobile Terminals is to optimize them for operation in the vicinity of the user body. The presence of a lossy human tissue in the Antenna's near field has an adverse effect on the radiator's performance. The focus of this paper is on studying the change in the Antenna performance due to the change in the dielectric properties of the human hand holding the mobile Terminal. The investigation is conducted by using an Antenna array consisting of two identical and symmetrical PIFA Antennas covering the frequency band from 5.8 GHz to 7.7 GHz. Several different values of the complex permittivity are assigned to a human hand phantom in the numerical simulations and it is found that the variation of the complex relative permittivity within a large range of values does not change largely the S-parameters and radiation efficiency of the Antenna.

  • Pattern-reconfigurable mobile Terminal Antenna system for MIMO and link stabilization in LTE
    12th European Conference on Antennas and Propagation (EuCAP 2018), 2018
    Co-Authors: Igor Syrytsin, Henrik A. Vesterager, Soren B. Norgaard, Lasse Thomsen, Samantha Caporal Del Barrio, Gert Frølund Pedersen
    Abstract:

    In this paper, a pattern reconfigurable mobile phone Antenna system for enhanced data rates in the LTE communication scheme is proposed. The three driven Antennas are designed with a resonant frequency of 2.6 GHz (Band VII). Passive elements are utilized in the design in order to change the radiation pattern direction of the proposed Antennas. The designed Antennas are primarily made to obtain pattern reconfigurability in data mode, where the phone is held either vertically with one hand or horizontally with two hands. Seven different radiation pattern directions are achieved with the proposed Antenna setup. With the use of RF switches and tuning devices, such as a programmable array of capacitors (PACs), this architecture can be implemented in handheld Terminals. In this work, prototypes with fixed architecture and different lengths of passive elements are presented. Finally, the MIMO performance of the system is investigated by calculating the envelope correlation coefficients, which are under 0.25 in the band of interest.

  • On Small Terminal Antenna Correlation and Impact on MIMO Channel Capacity
    IEEE Transactions on Antennas and Propagation, 2012
    Co-Authors: Boyan Yanakiev, Jesper Ødum Ødum Nielsen, Morten Christensen, Gert Frølund Pedersen
    Abstract:

    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.