Browsing by Author "Haneda, Katsuyuki"

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  • 3-D Modeling of Human Hands for Characterizing Antenna Radiation from a 5G Mobile Phone
    (2022) Vaha-Savo, Lauri; Koivumaki, Pasi; Haneda, Katsuyuki; Icheln, Clemens; Chen, Jingjing
     A4 Artikkeli konferenssijulkaisussa
    A method to obtain the three-dimensional (3D) model of a hand for an antenna-hand interaction analysis of a mobile phone is presented. The radiation and reception performance of millimeter-wave signals is more susceptible to intervention by a user's hand than that of legacy below-6 GHz radios. Hand models representing a wide range of natural handgrips of mobile phone users are therefore essential. The 3D modeling is based on the photogrammetry using a video footage of a hand. Multiple 3D models of natural handgrips can be obtained with reasonable efforts. The radiation performance of a canonical antenna array implemented into a mobile phone sized chassis is evaluated using a developed series of 3D hand models, showing the uncertainty of repeatable antenna-hand interaction analyses.
  • 3D Printed Cascaded Cavity-Backed Millimeter-Wave Filtering Antenna
    (2024) Xue, Bing; Jiang, Fan; Haneda, Katsuyuki; Yang, Xiantao; Icheln, Clemens
     A4 Artikkeli konferenssijulkaisussa
    In this manuscript, a cascaded filtering antenna structure is proposed. To realize this concept, we leverage the cavity-backed slot antenna as a foundation and take advantage of cutoff frequencies of waveguides to achieve it in the millimeter-wave (mmW) bands. The working principle and parameter analyses are introduced. Subsequently, we present the fabrication process and measurement results, which are then compared with simulation results. The obtained results demonstrate acceptable performance in terms of reflection coefficients and radiation patterns. Furthermore, by comparing our proposed antenna with published works, we highlight its advantages in terms of out-of-band rejection and similar beam width in E-plane and H-plane.
  • 3D printed horn antennas for millimeter wave and sub-THz bands
    (2024) Vähä-Savo, Lauri; Luoma, Iida; Icheln, Clemens; Haneda, Katsuyuki
     A4 Artikkeli konferenssijulkaisussa
    Three-dimensional (3D) printing has grown in popularity in many fields including antenna manufacturing. Fast and low-cost prototyping of lightweight products is desired for many electronic applications. This paper presents Ka- and D-band vertically polarized sectoral horn antennas, which are manufactured using 3D printing technologies. Dimensions of both antennas are based on reference metallic antennas. 3D printed antennas are compared against metallic antennas in terms of reflection coefficients, maximum realized gain, and half-power beamwidth to show their efficacy. The 3D printed antennas at both bands reproduce the beam shapes of the respective metallic reference antenna while their maximum realized gain is on average 3 dB lower than the reference due to surface roughness and different feeding structures that affect matching.
  • 6G Radio Requirements to Support Integrated Communication, Localization, and Sensing
    (2022) Wymeersch, Henk; Parssinen, Aarno; Abrudan, Traian E.; Wolfgang, Andreas; Haneda, Katsuyuki; Sarajlic, Muris; Leinonen, Marko E.; Keskin, Musa Furkan; Chen, Hui; Lindberg, Simon; Kyosti, Pekka; Svensson, Tommy; Yang, Xinxin
     A4 Artikkeli konferenssijulkaisussa
    6G will be characterized by extreme use cases, not only for communication, but also for localization, and sensing. The use cases can be directly mapped to requirements in terms of standard key performance indicators (KPIs), such as data rate, latency, or localization accuracy. The goal of this paper is to go one step further and map these standard KPIs to requirements on signals, on hardware architectures, and on deployments. Based on this, system solutions can be identified that can support several use cases simultaneously. Since there are several ways to meet the KPIs, there is no unique solution and preferable configurations will be discussed.
  • Above-100 GHz wave propagation studies in the european project hexa-X for 6G channel modelling
    (2021-06-08) Kyosti, Pekka; Haneda, Katsuyuki; Conrat, Jean Marc; Parssinen, Aarno
     A4 Artikkeli konferenssijulkaisussa
    We describe capabilities and plans to characterize above 100 GHz radio channel and propagation effects as part of a 6G research project Hexa-X. The starting point is the existing knowledge of radio propagation gathered by prior measurement and theoretical studies. Then we define measurement equipment, planned or performed campaigns, and discuss some challenges related to measurements at upper mm-wave frequencies. For several reasons the channel measurements are more time consuming on higher frequencies and it is not easy to collect enough data for statistical analysis. Hence we briefly introduce a stored channel model that will be developed based on the gathered channel measurement data. This initial channel model can be used as it is for physical layer studies through simulations and also as a basis for future channel models.
  • Analyses of Beamspace MIMO Channels at 142GHz
    (2024-01-01) De Guzman, Mar Francis; Tervo, Nuutti; Kyosti, Pekka; Haneda, Katsuyuki
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    This letter presents the analyses of a single-user beamspace multiple-input-multiple-output (MIMO) on measured indoor and outdoor channels at 142 GHz. The rank is evaluated under different antenna sizes, number of beams, and thresholds. We assume a total power constraint at the transmitter that results in a decrease in a signal-to-noise ratio as the link distance increases. When using spatial multiplexing, the indoor and outdoor sites demonstrate an average capacity gain of 2× and 1.5× at link distances below 60 m. Also, the rank for our measured 142 GHz channels is comparable to that at 60 GHz channels but significantly lower than the rank at 5 GHz channels reported in the literature. We also found that at 142 GHz, the indoor and outdoor sites have median ranks of 3.0 and 1.7 for the small-antenna case, and 4.9 and 2.4 for the large-antenna case assuming a rank threshold of 20 dB. The indoor site has a rank higher by 1.8 than the outdoor site, regardless of the antenna size. The rank decreases by only 20% and 15% for indoor and outdoor scenarios when the beam density is halved, allowing a significant reduction in implementation complexity of the beamspace MIMO without remarkably reducing the rank.
  • Analysis of Uplink and Downlink Spatial Channel Reciprocity When Using Asymmetric Transceiver
    (2024) Zhang, Peize; Kyosti, Pekka; Guzman, Mar Francis De; Haneda, Katsuyuki; Parssinen, Aarno
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    A novel millimeter-wave massive MIMO system using asymmetric transceiver, i.e., unequal number of transmitting (Tx) and receiving (Rx) radio frequency chains, is expected to maintain the advantages of conventional fully digital beamforming architectures, but partly reduce the implementation cost and power consumption. However, uplink and downlink radio channels may become non-reciprocal due to the different dimensions of Tx-Rx antenna arrays. In this paper, we analyze the reciprocity of radio channels observed by practical antenna patterns with different beamwidths. Two metrics are leveraged to measure spatial channel reciprocity based on 142 GHz outdoor channel measurement data and 28 GHz indoor ray-tracing simulation data. The power angular spectrum reciprocity of uplink and downlink radio channels does not hold when the beam pattern of base station Tx array becomes much narrower than that of Rx array. Meanwhile, it becomes increasingly likely that in the extreme case (e.g., significant beamwidth difference between Tx and Rx beam patterns), pronounced angle reciprocity can still be observed in the sparse channels with less multipath components.
  • Analysis of Wave-interacting Objects in Indoor and Outdoor Environments at 142 GHz
    (2023-12-01) Guzman, Mar Francis De; Haneda, Katsuyuki
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    In this article, an analysis of wave-object interactions is presented for an entrance hall and on a street of a residential area at 142 GHz. Single-directional channel sounding and the resulting spatiotemporal propagation path estimates are fused with the detailed geometry of the environment through a ray-launcher. The improved ray-launcher accounts for higher order reflections and realizes high correspondence of the measured paths on the geometry, allowing us to analyze wave-object interaction. In channels without line-of-sight, first- and second-order reflections contribute about 60% of the total power. Large interior and exterior walls of buildings are found most influential to the multipath channel. About half of the total received power in some links can be attributed to the reflections on small objects such as pillars and staircases in indoor and lampposts in outdoor cases. While large objects produce most of the clusters to the channel, there are links where small objects generate up to four clusters. The obtained knowledge of wave-object interaction at 142 GHz serves as guidelines to set up site-specific and geometry-based channel modeling at the frequency.
  • Antenna system design for improved wireless capsule endoscope links at 433 MHz
    (2019-04-01) Suzan Miah, Md; Khan, Ahsan Noor; Icheln, Clemens; Haneda, Katsuyuki; Takizawa, Ken Ichi
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Wireless capsule endoscopy (WCE) systems are used to capture images of the human digestive tract for medical applications. The antenna is one of the most important components in a WCE system. In this paper, we present novel small antenna solutions for a WCE system operating at the 433 MHz ISM band along with a link budget analysis. The in-body capsule transmitter uses an ultrawideband outer wall conformal loop antenna, whereas the on-body receiver uses a printed monopole antenna with a partial ground plane. A colon-equivalent tissue phantom and CST Gustav voxel human body model were used for the numerical studies of the capsule antenna. The simulation results in the colon-tissue phantom were validated through in vitro measurements using a liquid phantom. According to the phantom simulations, the capsule antenna has -10 dB impedance matching from 309 to 1104 MHz. The ultrawideband characteristic enables the capsule antenna to tolerate the detuning effects due to electronic modules in the capsule and due to the proximity of various different tissues in gastrointestinal tracts. The same design methodology was applied to on-body antennas followed by in vitro and ex vivo measurements for validation. The on-body antenna exceeds -10 dB impedance matching from 385 to 502 MHz both in simulations and measurements. The path loss for the radio link between an in-body capsule transmitter and an on-body receiver using our antenna solutions, in simulations and measurements, is less than 50 dB for any capsule orientation and location, ensuring sufficient signal level at the receiver, hereby enabling an improved capsule endoscope.
  • Assessment of mmWave Handset Arrays in the Presence of the User Body
    (2021-09) Ballesterossanchez, Christian; Vaha-Savo, Lauri; Haneda, Katsuyuki; Icheln, Clemens; Romeu, Jordi; Jofre, Lluis
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The emergence of mobile terminals operating at millimeter-wave frequencies necessitates the ability to evaluate the effect the environment, and in particular, users have on their radiation properties. Some studies evaluated the shadowing effects of a hand or an entire body for simple antenna configurations. This letter proposes a method for reliably predicting the performance of different array geometries in the presence of the users when they operate the mobile with one or with two hands. In practice, the way a mobile is operated is varying strongly between users, and hence, it is of great interest to draw a methodology to both numerically and experimentally evaluate any handset design in a large number of use cases in a repeatable manner. The use of numerical models and realistic phantoms allow high repeatability when evaluating the terminal radiation under real use conditions. Both the simulated body and the human phantom are used to study the field scattering from the handset arrays subject to the user interaction, yielding consistent results between them. Results suggest that shadowing by the user's torso usually decreases gain between 20-30 dB close to the region of the user. The user posture largely affects the spherical coverage, particularly for those antennas close to the corners in a two-hand mode.
  • Attainable capacity of spatial radio channels: A multiple-frequency analysis
    (2016-12-08) Haneda, Katsuyuki; Nguyen, Sinh Le Hong; Khatun, Afroza
     A4 Artikkeli konferenssijulkaisussa
    This paper reports an attainable channel capacity and spatial degrees-of-freedom of multiple-antenna radio channels at 15, 28 and 61 GHz. The analysis is based on channel sounding in a same street canyon. The attainable capacity is evaluated so that it depends only on the antenna aperture size but is independent of implementation of antenna elements on the aperture. The analysis shows that multipath richness decreases as the frequency increases, as indicated by the smaller spatial degrees-of-freedom at higher frequencies for the same electrical aperture size of the receive antenna. The analysis furthermore reveals that channels at the three radio frequencies can attain almost the same level of capacity for a given transmit power and physical size of the receive antenna. The result is explained by a greater electrical size of the antenna aperture at the higher frequencies that can leverage higher gains and finer angular resolution and hence normalize the availability of fewer multipaths.
  • Base station radome design for 5G and beyond
    (2024) Vähä-Savo, Lauri; Shoghibadr, Nasrin; Icheln, Clemens; Haneda, Katsuyuki
     A4 Artikkeli konferenssijulkaisussa
    Increasing data use forces mobile communication to move higher carrier frequencies. The 71-76 GHz band has been newly assigned for communication use. The base station needs radome for protection against the environment. At millimeter waves, the thickness of the radome may become significant compared to the wavelength, making the radome design more challenging. In this manuscript, we design and manufacture two planar radomes, i.e., a single-layer radome and an A-sandwich radome with dielectric lenses. These two radomes are evaluated using maximum realized gain and a new metric gain envelope variation. The A-sandwich lens radome achieves higher realized gains with smaller gain envelope variation than traditional single-layer radome.
  • Characterization of vehicle penetration loss at wireless communication frequencies
    (2012) Virk, Usman Tahir
     School of Electrical Engineering | Master's thesis
    Automotive window films are widely used for heat rejection, protection from ultraviolet radiations and glare control purposes. For an increased performance, these films are usually metallized since metals effectively reflect the impinging electromagnetic radiations. The expend of metallization in these films may affect the communication of radio signals into vehicles. In this perspective, the provision of reliable in-vehicle coverage is a major goal of both wireless network providers and automotive industry. In order to quantify the effects of automotive window films on communication signals inside a vehicle, this research study was undertaken with industrial cooperation. The thesis presents the characterization of Vehicle Penetration Loss (VPL) at major wireless communication frequencies based on empirical and numerical evaluation and by exploiting different window coatings including a commercially available automotive window film and Aluminium metal foil. The research involves ultra-wideband (UWB) car measurement campaign for the frequency range of 0.6-6.0 GHz in an indoor industrial environment at an isolated storage facility in Helsinki utilizing a regular sized hatchback car. Several realistic measurement scenarios were considered to obtain large measurement sets. The measurement data was post-processed using fine algorithms to exploit various channel characteristics to gain sufficient understanding of associated propagation phenomenon. Window films were also exclusively measured in a specialized environment to accurately assess the associated penetration loss. Apart from measurements, numerical analysis based on Finite-difference time-domain (FDTD) method for the assessment of VPL was carried out at discrete frequencies, 900 MHz and 1.2 GHz. The numerical approach can serve as a future alternate to measurements provided that adequate computational resources are available. The results infer that the use of metallized automotive films can severely affect the communication of radio signals into vehicles.
  • Compact massive MIMO antenna array for small 5G base stations
    (2016-08-24) Ali, Muhammad
     Sähkötekniikan korkeakoulu | Master's thesis
  • Comparing radio propagation channels between 28 and 140 GHz bands in a shopping mall
    (2018) Nguyen, Sinh; Järveläinen, Jan; Karttunen, Aki; Haneda, Katsuyuki; Putkonen, Jyri
     A4 Artikkeli konferenssijulkaisussa
    In this paper, we compare the radio propagation channels characteristics between 28 and 140 GHz bands based on the wideband (several GHz) and directional channel sounding in a shopping mall environment. The measurements and data processing are conducted in such a way to meet requirements for a fair comparison of large- and small- scale channel parameters between the two bands. Our results reveal that there is high spatial-temporal correlation between 28 and 140 GHz channels, similar numbers of strong multipath components, and only small variations in the large-scale parameters between the two bands. Furthermore, when including the weak paths there are higher total numbers of clusters and paths in 28 GHz as compared to those in 140 GHz bands. With these similarities, it would be very interesting to investigate the potentials of using 140 GHz band in the future mobile radio communications.
  • Comparison of Indoor Propagation Channels at 28 GHz and 140 GHz Bands
    (2024) De Guzman, Mar Francis; Haneda, Katsuyuki
     A4 Artikkeli konferenssijulkaisussa
    In this paper, a comparison between the measured 28 GHz and 140 GHz channels in an entrance hall is presented. The path loss, angular spread, delay spread, and composite power angular spectrum (PAS) are evaluated and compared with reference indoor channels in an office, existing model, and shopping mall. The existing model and office path loss curves align with the path loss of line-of-sight (LOS) and non-LOS (NLOS) links, respectively. When using the full dynamic range, the angular spread does not change with frequency, while the delay spread decreases with frequency in the entrance hall. The differences in angular spread and delay spread vary between the entrance hall and other indoor environments due to differences in layout. The composite PAS at both bands are similar for both LOS and NLOS links. The channels have larger angular and delay spread at 140 GHz than 28 GHz when the same dynamic range is used.
  • Comparison of Measured and Simulated Radiation from 5G Cellphone Antennas with Hand Phantoms
    (2023) Xue, Bing; Haneda, Katsuyuki; Icheln, Clemens; Vähä-Savo, Lauri
     A4 Artikkeli konferenssijulkaisussa
    In this manuscript, hand effects on cellphone antennas at 5G millimeter-wave frequencies are evaluated through measurements using hand phantoms and are compared with results from electromagnetic simulations. First, two configurations of a dual-polarized 4-element linear antenna array operating at 28 GHz are introduced. One-hand and two-hand physical phantoms and their numerical models for electromagnetic simulations are illustrated. Then, the array evaluation metric, i.e., spherical coverage, is introduced to assess statistics of realized gain across the solid angle. Next, antenna measurement setups are implemented for the two antenna arrays combined with the two physical hand phantoms. Finally, the spherical coverage and the corresponding cumulative distribution function are calculated. Differences in the realized gains derived from simulated and measured antenna arrays are about 1 dB at the median levels of the cumulative distribution. The differences are comparable to those observed when real hands are used in measurements instead of phantom hands [1].
  • Complex Permittivity Characterization of Low-Loss Dielectric Slabs at Sub-THz
    (2024-10-14) Xue, Bing; Haneda, Katsuyuki; Icheln, Clemens; Ala-Laurinaho, Juha; Tuomela, Juha
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    This paper presents a novel low-complexity method to characterize the permittivities of low-loss dielectric slabs at millimeter-wave and sub-terahertz bands. The method assumes plane-wave illumination of the material under test and utilizes reflected fields on two air-material interfaces, resolved through a sufficiently wide-band measurement. Unlike conventional methods, it does not need a reference measurement using a metal plate and a back metal plate. The applicability of the method is discussed. The misalignment of a reference plane and the effects of the gap between the back metal and the material under test are analyzed for published reflected-field based methods to show the advantages of the method. Finally, the proposed method is applied to estimate the permittivities of both plexiglass with 30 mm thickness and nylon with 21 mm thickness across 140-210 GHz and compared against the free-space transmission method, showing good agreement. The proposed method is suitable for permittivity characterization of low-loss materials when a wide-band plane-wave measurement is possible.
  • Design of a Reference Dipole-Loop Antenna Array at 28 GHz
    (2019-03-01) Miah, Md Suzan; Heino, Mikko; Icheln, Clemens; Haneda, Katsuyuki
     A4 Artikkeli konferenssijulkaisussa
    This paper proposes an array antenna at 28 GHz that can be used to measure polarimetric omni-directional pathloss. The array consists of a printed microstrip dipole and loop with an integrated tapered balun structure. The design and experimental results of low profile microstrip dipole and loop antenna show wideband matching and radiation performance. Over 6 GHz of -10 dB impedance matching bandwidth has been achieved for the dipole, whereas the loop shows 0.2 GHz ranging from 27.9 to 28.1 GHz. A fairly good agreement between the simulated and measured radiation pattern validates our simulation method. The omni-directional behaviors of both dipole and loop make it suitable as a reference antenna for over-the-air antenna testing at 28 GHz.
  • Design of cost-effective channel emulator at 28 GHz for over-the-air testing of antennas in portable devices
    (2021-08-23) Kansara, Maharshi
     Sähkötekniikan korkeakoulu | Master's thesis