| 1. |
- Alfonso Alos, Esperanza, 1979, et al.
(author)
-
Gap waveguide components for millimeter-wave systems. Couplers, filters, antennas, MMIC packaging
- 2012
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9784885522703 ; , s. 243-246
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Conference paper (peer-reviewed)abstract
- Design of passive components (couplers, filters and antennas) and MMIC packaging validation intended for RF front ends for microwave links at 38 GHz using gap waveguide technology have been shown. The use of this technology allows all-in-one integration of receiver, transmitter, and diplexer including the antenna into one mechanical unit. These initial designs and studies have been made at the microwave band for validation and measurement purposes, and for comparison with existing technology. They represent the first step towards the application of gap waveguides to millimeter-wave systems, where gap waveguides could have a large potential.
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| 2. |
- Carlsson, Jan, 1962, et al.
(author)
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Antenna Research at CHASE – Chalmers Antenna Systems Excellence Centre
- 2012
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9784885522703 ; , s. 215-218
-
Conference paper (peer-reviewed)abstract
- Chase is one of a total of eighteen 'VTNN Excellence Centres' that are funded by VINNOVA, the Swedish Governmental Agency for Innovation Systems. The aim of these centres is to provide a forum for collaboration between the private and public sectors, universities and colleges, research institutes and other organisations that conduct research. The Chase centre was started in 2007 and has a budget of at least 23 million Euro over ten years with cash and in kind contributions. The research activities in Chase cover antennas and antenna system aspects, and the industrial interests are mainly in Wireless Communications, Remote Sensing and Medical Applications of Microwaves. The projects are chosen based on industrial needs, usefulness for society and global sustainability.
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| 3. |
- Algaba Brazalez, Astrid, 1983, et al.
(author)
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Evaluation of losses of the ridge gap waveguide at 100 GHz
- 2013
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467353175 ; , s. 1456-1457
-
Conference paper (peer-reviewed)abstract
- An evaluation of losses of the Ridge Gap Waveguide (r-GAP) at 100 GHz has been developed in terms of Quality Factor. For this aim, an r-GAP resonator has been designed, simulated and measured. The feeding to the circuit is provided via a transition from Micostrip-to-Ridge Gap Waveguide based in electromagnetic coupling in order to ensure compatibility with the available probe stations.
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| 4. |
- Algaba Brazalez, Astrid, 1983, et al.
(author)
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Investigation of a Microstrip-to-Ridge Gap Waveguide transition by electromagnetic coupling
- 2012
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467304627 ; , s. 1-2
-
Conference paper (peer-reviewed)abstract
- A transition from Microstrip to Ridge Gap Waveguide (RGW) has been studied and numerically analyzed in terms of S parameters. The RGW technology shows potential to be used up to THz frequencies. Therefore, good transitions are needed in order to make possible the measurements of RGW components at frequencies above 100 GHz.
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| 5. |
- Cismasu, Marius, et al.
(author)
-
Optimal Charges and Currents on Small Wire Antennas
- 2012
-
In: IEEE Antennas and Propagation Society International Symposium (APSURSI), 2012. - 1522-3965 .- 1947-1491. - 9781467304610 ; , s. 1-2
-
Conference paper (peer-reviewed)abstract
- The optimum surface charge on a thin wire antenna is computed using a variational formulation in the low-frequency limit. This charge and its corresponding current are compared with simulation results for self resonant structures. The comparison shows that the currents and charges on self resonant structures resemble those in the static limit to a great extent.
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| 6. |
- Engvall, Erik K, 1984, et al.
(author)
-
A study of uncertainty models in a reverberation chamber at NIST
- 2012
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467304627
-
Conference paper (peer-reviewed)abstract
- The reverberation chamber has become a good alternative for over-the-air (OTA) testing of small antennas. Here the uncertainty of total radiated power measurements is evaluated for a reverberation chamber at National Institute of Standards and Technology (NIST), Boulder, Colorado. A procedure for measuring the uncertainty based on the standard deviation of nine different antenna orientations in the RC has been used.
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| 7. |
- Fayazi, Seyedeh Shaghayegh, et al.
(author)
-
Microwave imaging of near-field object using ultra-wideband synthetic aperture radar algorithm
- 2012
-
In: 2012 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI). - 1522-3965. - 9781467304627
-
Conference paper (peer-reviewed)abstract
- A simple procedure that suppresses artefact from ultra-wideband (UWB) synthetic aperture radar (SAR) images is proposed and verified using experimental data. The proposed imaging solution is useful for imaging small objects located in the near-field region with less ambiguity.
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| 8. |
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| 9. |
- Hammar, Arvid, 1986, et al.
(author)
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A 340 GHz High Gaussicity Smooth Spline Horn Antenna for the STEAMR Instrument
- 2014
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781479935383 ; , s. 649-650
-
Conference paper (peer-reviewed)abstract
- We present the design, fabrication and measure-ments of a smooth walled spline feed horn antenna for the satellite borne climate research instrument STEAMR operating at 340GHz. A method has been developed which, for a certain desired beam waist, can be used to optimize the horn profile for high Gaussicity and ultra-low sidelobes. The simulated performance of the horn achieves a beam waist of 1.9 mm over the band 323-357 GHz with Gaussian coupling efficiency exceeding 98%. The peak cross-polar sidelobes are below -28 dB over the required frequency band. For cost effective manufacturing with high repeatability, the smooth wall spline profile is drilled in out from a metal block using a custom made broach. To validate the design and fabrication, planar measurements of the phase and amplitude have been performed and from measured E-field vital horn parameters have been extracted.
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| 10. |
- Harrysson, Fredrik, et al.
(author)
-
Evaluation of user hand and body impact on multiple antenna handset
- 2010
-
In: [Host publication title missing]. - 1522-3965 .- 1947-1491. - 9781424449675
-
Conference paper (peer-reviewed)abstract
- From our experimental investigation of multiple-antenna performance and user impact of a realistic mobile terminal setup, we find that apart from the important loss of efficiency due to the user hand, the impact on the individual antennna elements and the directional impact of the user body shadowing have quite small influence on the diversity and capacity performance. It is found that the top and bottom placement of antennas within the handset case are the most efficient to be used with up to two antenna elements. There are, however, significant diversity and capacity gain that can be explored by using four distributed antennas even if only two radio chains are available through hybrid selection and combining schemes. It was also found that the practical method of choosing antennas based on signal power for 2 branch MIMO with 4 available handset antennas, performs well compared to the optimal solution.
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| 11. |
- Hussain, Ahmed, 1985, et al.
(author)
-
Modeling system throughput of single and multi-port wireless LTE devices
- 2012
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467304627
-
Conference paper (peer-reviewed)abstract
- We have recently introduced a simple theoretical model for estimating the relative throughput of LTE devices. We validated the model through measurements performed in reverberation chamber for 1×2 SIMO with 90ns channel delay spread. In the present paper, we extend our previous study to compare the frequency diversity offered by different channel delay spreads emulated in reverberation chamber for SISO and 1×2 SIMO configurations
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| 12. |
- Kildal, Per-Simon, 1951
(author)
-
Metasurfing since 1987 - A personal story involving soft and hard surfaces, EBG surfaces, cloaking, gap waveguides and mass production
- 2014
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. ; , s. 529-530
-
Conference paper (peer-reviewed)abstract
- This paper will describe my personal experiences with what today is referred to as metamaterials, and in particular in my case metasurfaces. My journey starts with the introduction of a concept of soft and hard surfaces in 1988, being a generalization of the corrugated surface, and today most conveniently represented by canonical PEC/PMC strip grids. The first industrial application of the soft surface was the patent-protected hat feed in 1987. This has until now been manufactured in more than 940 000 copies mainly for Ericsson's successful MINILINK product. The anisotropic soft surface is a forerunner of the isotropic EBG surface appearing around year 2000, and the hard surface was used for cloaking 10 years before cloaking became a popular research topic in 2007. The concept of soft and hard surfaces has since 2009 developed into a novel gap waveguide technology. The gap waveguide technology is used to package microstrip and CPW circuits, but also to replace them. The gap waveguides can have similar low-loss performance as solid rectangular waveguides, but they can be realized in a much simpler way in particular at millimeter- and submillimeterwave frequencies. Good performance has been demonstrated for filters, transitions, MMIC packaging, corporate distribution networks, and slot and horn array antennas. The first commercial applications can come soon, probably at 60 GHz.
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| 13. |
- Kildal, Per-Simon, 1951, et al.
(author)
-
Performance of different theoretical small antennas in isotropic 3-D and horizontal 2-D multipath environments with application to OTA testing
- 2010
-
In: 2010 IEEE International Symposium on Antennas and Propagation, Toronto, July 11-17, 2010. - 1522-3965. - 9781424449682
-
Conference paper (peer-reviewed)abstract
- We have studied the performance of antennas in inherently polarization-balanced horizontal 2-D multipath environments with angles of arrival in the horizontal plane only. The average received power may vary up to 3 dB depending on type of small antenna and its orientation, and, the observed polarization balanced may be anything between +3 and 3 dB, depending on the antenna by which it is measured.
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| 14. |
- kishk, M. A., et al.
(author)
-
Electromagnetic scattering from circular cylinders with PEC/PMC boundaries
- 2010
-
In: 2010 IEEE International Symposium on Antennas and Propagation, Toronto, July 11-17, 2010. - 1522-3965. - 9781424449675
-
Conference paper (peer-reviewed)abstract
- The electromagnetic scattering from a circular cylinder with helical PEC/PMC boundary due to oblique plane wave incidence was analyzed using the series solution. The solution was verified using the method of moments.
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| 15. |
- Klein, Benjamin, 1981, et al.
(author)
-
System noise calculations over the decade bandwidth of the Eleven feed for radio telescope applications
- 2010
-
In: 2010 IEEE International Symposium on Antennas and Propagation, Toronto, July 11-17, 2010. - 1522-3965. - 9781424449682
-
Conference paper (peer-reviewed)abstract
- The ability to cool the entire system improves system performance by a factor of two to four times; for the cooled case. This requires ambient systems to increase reflector diameters in proportion to achieve similar sensitivity. Additionally, the requirements on matching are relaxed in cooled systems, as the not-included variation of the LNA due to the noise mismatch is much smaller in a cooled system than in a non-cooled system. The calculations presented provide a meaningful reference to quickly compare systems, for both engineers and scientists. However, further work is ongoing into more accurate noise models and computer simulations. There is also ongoing work to verify results experimentally.
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| 16. |
- Li, Hui, et al.
(author)
-
Generating multiple characteristic modes below 1 GHz in small terminals for MIMO antenna design
- 2013
-
In: IEEE International Symposium on Antennas and Propagation, 2013. - 1947-1491 .- 1522-3965. - 9781467353175 ; , s. 180-181
-
Conference paper (peer-reviewed)abstract
- Designing multiple antennas in small terminals at frequency bands below 1 GHz is challenging due to severe mutual coupling among antenna elements. The severe coupling is often the result of simultaneous excitation of the fundamental characteristic mode of the terminal chassis by more than one antenna element. In this work, we propose to solve the coupling problem by manipulating the chassis structure to allow more than one characteristic mode to resonate at frequencies below 1 GHz. To demonstrate our design concept and its practicality, we show the opportunistic use of the metallic bezel popular in smartphone design for obtaining two characteristic modes that can be efficiently excited by antenna elements at 0.81 GHz. Due to the inherent orthogonality of the modes, proper excitation of these modes by two antenna elements will result in orthogonal radiation patterns and high isolation between the antenna ports. Therefore, the proposed approach enables the effective use of the chassis to achieve MIMO antennas with good performance.
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| 17. |
- Lötbäck Patané, Christian, 1985, et al.
(author)
-
LTE MIMO throughput measurement method for characterization of multi-antenna terminal performance
- 2011
-
In: 2011 IEEE International Symposium on Antennas and Propagation, Spokane, USA, 3-8 July, 2011. - 1522-3965. - 9781424495627 ; , s. 43-46
-
Conference paper (peer-reviewed)abstract
- This paper presents experiences and results from LTE MIMO throughput measurements of a USB dongle in a reverberation test system. The measurements are performed with the dongle itself and also when it is connected to external diversity antennas with high and low correlation. Three different maximum bit rates are used, 59, 70 and 81 Mbps. The results illustrate that it is possible to separate a good antenna design from a bad from reverberation chamber measurements. Also, the effect of using a laptop test fixture, or a laptop dummy, instead of having the host computer present in the chamber, is demonstrated. It is shown that the noise induced by the host computer degrades the performance of the dongle.
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| 18. |
- McPhedran, Ross, et al.
(author)
-
Resonances and Fields near Metamaterial Inclusions
- 2012
-
In: Antennas and Propagation Society International Symposium (APSURSI), 2012 IEEE. - 1522-3965 .- 1947-1491. - 9781467304627
-
Conference paper (peer-reviewed)abstract
- We consider systems of particles in two dimensions with negative dielectric permittivity and sharp corners. The field divergences near the corners of the inclusions are non-square-integrable for negative permittivities in a range depending on the corner angle, and the leading term for small distances is provided by the static term. We have developed a highly accurate numerical method which uses adaptive techniques to resolve field behaviour near the corners. We use this to elucidate the resonant spectrum associated with the effective permittivity of arrays of such particles, and in particular its behaviour as the particles approach touching.
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| 19. |
- Miers, Zachary, et al.
(author)
-
Design of multi-antenna feeding for MIMO terminals based on characteristic modes
- 2013
-
In: IEEE International Symposium on Antennas and Propagation, 2013. - 1522-3965 .- 1947-1491. - 9781467353175 ; , s. 182-183
-
Conference paper (peer-reviewed)abstract
- Conventional antennas in single-antenna terminals that resonate at frequencies lower than 1 GHz usually rely on the chassis as the main radiator. To effectively exploit chassis excitation for MIMO terminals, each of the multiple antennas is required to excite one distinct chassis mode. However, in today's terminals, there is typically only one chassis mode that can radiate efficiently at frequencies below 1 GHz. Fortunately, it has been shown that minor modifications in the chassis structure can cause more than one mode to resonate at these frequencies. Nevertheless, proper antenna feeding methods are needed to practically tap into these modes. In this paper, we propose a general technique to feed orthogonal chassis modes of a given conducting structure using the theory of characteristic modes. By separating a radiating structure into individual modal currents, the near field radiating properties are exploited for capacitive or inductive feeding without significant coupling to other orthogonal modes of radiation. As a proof of concept, we apply the technique to feed a modified terminal chassis that has two significant characteristic modes at 0.89 GHz.
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| 20. |
- Miers, Zachary, et al.
(author)
-
Design of multimode multiband antennas for MIMO terminals using characteristic mode analysis
- 2014
-
In: IEEE International Symposium on Antennas and Propagation, 2014. - 1947-1491 .- 1522-3965. - 9781479935383 ; , s. 1429-1430
-
Conference paper (peer-reviewed)abstract
- Characteristic mode analysis provides unparalleled insights into designing high performance multiple-input multiple-output (MIMO) terminal antennas at frequencies where the antenna elements are constrained to be electrically small. Conventionally, an electrically small single-antenna utilizes the fundamental characteristic mode of the terminal chassis to obtain sufficient bandwidth while maintaining high radiation efficiency. However, modern MIMO terminals require two or more antennas per frequency band, and they tend to excite the same fundamental chassis mode, resulting in severe coupling and correlation, and poor overall system performance. Recently, characteristic mode analysis of the chassis is proposed to design highly efficient multimode multiband MIMO antennas with significant bandwidth using electrically small feed elements. Two distinct and excitable characteristic modes were created at frequencies above and below 1 GHz, for a typical smartphone’s form factor. This paper provides an overview of the method and highlights its versatility for practical implementation in standard plastic cased smartphones as well as in the popular metal-bezeled smartphones, with only minor modifications to the chassis.
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| 21. |
- Orlenius, Charlie, 1976
(author)
-
Antenna performance characterization of multi-antenna terminals used in Multiple-Input-Multiple-Output communication systems
- 2010
-
In: 2010 IEEE International Symposium on Antennas and Propagation, Toronto, July 11-17, 2010. - 1522-3965. - 9781424449675
-
Conference paper (peer-reviewed)abstract
- With new third and fourth generation mobile communication systems emerging, there has been an increased focus on the antenna performance of mobile terminals. Common for most new communication systems currently deployed and under development is the demand for multi-antenna technology, such as multiple-input-multiple-output (MIMO). In order to reach increased data rates it is essential to be able to make use of the potential spatial multiplexing gain of a multipath propagation environment. For design optimization of these multi-element antennas, a reliable and relevant measurement method for characterizing the antenna performance is important. In this paper, a method using the reverberation chamber is presented together with a discussion on how to analyze the results in order to distinguish good and bad antenna designs from each other.
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| 22. |
- Orlenius, Charlie, 1976, et al.
(author)
-
Evaluation of multi element antennas in reverberation chamber
- 2012
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467304627
-
Conference paper (peer-reviewed)abstract
- This paper focuses on the latest advances in the use of reverberation chambers for active device testing. Contained are description and comparison of different figure-of-merits that are applicable to multi element antennas, with a specific focus on LTE devices with MIMO capability. There are two new parameter concepts introduced: Modified Total Isotropic Sensitivity measurements to include MIMO signaling, and a Throughput Threshold Level for simplified quantification of data bit throughput measurement results.
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| 23. |
- Pucci, Elena, 1982, et al.
(author)
-
Design of a four-element horn antenna array fed by inverted microstrip gap waveguide
- 2013
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467353175 ; , s. 1226-1227
-
Conference paper (peer-reviewed)abstract
- The paper presents the design of a four-element slot coupled dual-mode horn array with microstrip gap waveguide as feed network. We present simulated results for return loss for the feed network both with and without the radiating horn array. We also compare results for two ways to generate the stopband of the parallel-plate modes: the ideal Perfect Magnetic Conductor used during the initial design, and the real bed of nails used in the practical realization. The study is performed at 60 GHz obtaining about 10% bandwidth.
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| 24. |
- Pucci, Elena, 1982, et al.
(author)
-
Evaluation of losses in microstrip gap waveguide for slot antennas applications
- 2012
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467304627 ; , s. 1-2
-
Conference paper (peer-reviewed)abstract
- The new microstrip gap waveguide supports a quasi-TEM mode in the air by the use of artificial magnetic conductors which force the field to travel in the air rather than in the substrate. This paper presents an evaluation of losses by measuring the Q-factor of a resonator made in this technology, made using a mushroom-type EBG surface. Losses are crucial when using printed circuits to feed slot antennas, thereby motivating this work. Comparisons with standard microstrip lines will be provided, showing promising results.
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| 25. |
- Quevedo Teruel, Oscar, et al.
(author)
-
On the Increase of the Efficiency and Bandwidth of Compact PIFAs based on SRR by Making Use of Lumped Capacitors
- 2010
-
In: 2010 IEEE International Symposium on Antennas and Propagation, Toronto, July 11-17, 2010. - 1522-3965. - 9781424449675
-
Conference paper (peer-reviewed)abstract
- In this communication, a new compact microstrip patch antenna based on shortcircuited SRRs is presented. This design, in its basic version, provides a dual band response. This initial configuration will be modified by making use of lumped elements (capacitors), in order to achieve a single band with large bandwidth or higher radiation efficiency.
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| 26. |
- Soh, P. J., et al.
(author)
-
Wearable textile antennas’ efficiency characterization using a reverberation chamber
- 2011
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. ; , s. 810-813
-
Conference paper (peer-reviewed)abstract
- Characterization of efficiency is an important consideration to ensure the proper operation of an all-textile wearable antenna. In this work, a small, novel textile antenna is designed based on a planar inverted-F structure (PIFA). The structure incorporates an edge-feeding plate, symmetrical design, and well-placed slot, in order to ease fabrication. A thin conductive textile, Pure Copper Polyester Taffeta Fabric (PCPTF), and fleece is used to fabricate the structure. The efficiency is then verified and measured using a commercial reverberation chamber. Observed results indicate excellent agreements between simulations and measurements.
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| 27. |
- Uz Zaman, Ashraf, 1975, et al.
(author)
-
Using lid of pins for packaging of microstrip board for descrambling the ports of Eleven antenna for radio telescope applications
- 2010
-
In: 2010 IEEE International Symposium on Antennas and Propagation, Toronto, July 11-17, 2010. - 1522-3965. - 9781424449682
-
Conference paper (peer-reviewed)abstract
- This paper presents the packaging solution for the microstrip part of the descrambling section of dual polarized Eleven antenna. The packaging solution is based on using artificial Perfect Magnetic Conductor (PMC) shielding instead of conventional metal shielding. The PMC shielding is realized with a metal pin surface, and these metal pins force the parallel plate cavity modes to vanish within the frequency range of interest, from 5 GHz to 13.5 GHz.
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| 28. |
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| 29. |
- Vasilev, Ivaylo, et al.
(author)
-
On user effect compensation of MIMO terminals with adaptive impedance matching
- 2013
-
In: IEEE International Symposium on Antennas and Propagation, 2013. - 1947-1491 .- 1522-3965. ; , s. 174-175
-
Conference paper (peer-reviewed)abstract
- Proximity of user has been established as a major cause of performance degradation in multiple-input multiple-output (MIMO) terminals. Here, we investigate the potential of adaptive impedance matching (AIM) to improve the performance of two MIMO terminals in a free space (FS) and a two-hand (TH) user scenario, assuming uniform 3D angular power spectrum for the incoming signal. The results show that lossless uncoupled AIM circuits can enhance the MIMO capacity of the terminals by up to 43% relative to standard 50 ohm terminations. In particular, the largest capacity gain is obtained in the terminal with good matching but narrower antenna bandwidth and worse isolation performance, for the TH scenario. On the other hand, the terminal with poorer matching but higher isolation and significantly larger bandwidth has lower average capacity in FS. However, it is more robust to user proximity, and hence it achieves only 8% capacity gain with AIM in the TH scenario. Therefore, antenna design parameters can significantly influence potential benefits of AIM in practice.
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| 30. |
- Warnick, K. F., et al.
(author)
-
Noise-based antenna terms for active receiving arrays
- 2012
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467304627
-
Conference paper (peer-reviewed)abstract
- For active receiving arrays with complex receiver chains, nonreciprocal components in the beamforming network, or digitally sampled and processed output signals, existing transmit-based antenna terms such as gain and radiation efficiency cannot be directly applied. Using the reciprocity principle to obtain an equivalence between the total power radiated by a transmitting antenna and the noise power at the output of a receiving antenna, a new set of more general, receiver-specific antenna terms have been obtained. For passive, reciprocal antennas, the new definitions are rigorously equivalent to existing definitions. The terms have received the IEEE Antenna Definitions Working Group's support for inclusion pending final approval by the Antenna Standards Committee in the next update of the IEEE standard for antenna terms.
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| 31. |
- Xiaoming, Chen, 1983, et al.
(author)
-
Simple calculation of ergodic capacity of lossless two-port antenna system using only S-parameters – Comparison with common Z-parameter approach
- 2011
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781424495634 ; , s. 1885-1888
-
Conference paper (peer-reviewed)abstract
- In this paper, we show how to correctly include overall antenna effects in a numerically generated Rayleigh channel matrix when calculating ergodic MIMO capacity of lossless multi-port antenna system located in rich isotropic multipath. The overall antenna effects can be included correctly using either impedance parameters (Z-parameter method) or scattering parameters (S-parameter method). These two methods are compared and validated by measurements in anechoic and reverberation chambers. A narrowband handset antenna with negligible ohmic loss is used for the measurements. There are very good agreements between the capacities obtained using both methods from anechoic chamber measurement and that from direct channel measurement in reverberation chamber.
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| 32. |
- Yang, Jian, 1960, et al.
(author)
-
Compact dual-polarized 1.2 - 10 GHz eleven feed by folding outer elements for large decade-bandwidth radio telescopes
- 2011
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781424495634 ; , s. 843-846
-
Conference paper (peer-reviewed)abstract
- The Eleven antenna is a log-periodic folded-dipole-pair array which has two unique radiation characteristics: constant beamwidth and fixed phase center location over decade bandwidth. Therefore, the Eleven antenna is very suitable as a feed for reflector antennas. This paper presents a new compact design of 1.2 - 10 GHz Eleven antenna by folding down the outermost elements of the array. By doing so, it is possible to put the Eleven feed inside a compact cryostat, which is critical for applications in radio telescopes. The new compacted Eleven antenna has only 40% volume of the original standard Eleven antenna with similar performance. Simulations and measurements have verified the design and are presented in the paper.
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| 33. |
- Yang, Jian, 1960, et al.
(author)
-
The Self-Grounded Bow-Tie Antenna
- 2011
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781424495634 ; , s. 1452-1455
-
Conference paper (peer-reviewed)abstract
- The self-grounded Bow-Tie is a new type ultra-wide band (UWB) small antenna. It is compact, simple and has low profile and directional UWB radiation characteristics. Simulations and measurements have shown its ultra-wideband performance, such as about 10 dB reflection coefficient and stable radiation patterns over a frequency range of 2 - 15 GHz, and good time-domain impulse response. Penetration ability of the antenna through a concrete wall has been also tested. Compared to a Vivaldi antenna, the test shows the superiority of the self-grounded Bow-Tie to the Vivaldi.
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| 34. |
- Yin, J., et al.
(author)
-
A 2-5 GHz circular Eleven antenna with improved BOR1 efficiency
- 2011
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781424495634 ; , s. 1247-1250
-
Conference paper (peer-reviewed)abstract
- This paper presents an improved Eleven antenna - the circular Eleven antenna, which has 0.3 dB higher BOR1 efficiency than previous models. In this way the aperture efficiency becomes higher when it is used as a feed for reflector antennas. The new feed is constructed by using circularly curved folded dipoles which are printed on four flat circuit boards, referred to as then petals as in previous models. The demonstration of the improvement is shown over the limited frequency range 2 - 5 GHz to reduce computation time.
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| 35. |
- Zamanifekri, A, et al.
(author)
-
Two octaves bandwidth passive balun for the Eleven feed for reflector antennas
- 2010
-
In: 2010 IEEE International Symposium on Antennas and Propagation, Toronto, July 11-17, 2010. - 1522-3965. - 9781424449682
-
Conference paper (peer-reviewed)abstract
- A new two octaves bandwidth balun is presented in the paper, which has a bandwidth of 3-13 GHz with a very compact size, -10 dB input reflection coefficient, low ohmic loss and large common mode suppression. A new descrambler circuit for the 2-13 GHz Eleven feed has been designed by using the new baluns, reducing from 4 twin-wire ports to 2 single-ended ports, one per polarization. The reflection coefficient of the whole Eleven antenna with the new descrambling circuit is below -8 dB over the frequency range of 3-13 GHz. Further improvement of the bandwidth of the new balun will be emphasized in the future work.
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| 36. |
- Zhang, Shuai, et al.
(author)
-
Compact UWB MIMO antenna for USB dongles with angle and polarization diversity
- 2012
-
In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 9784885522703 - 9781467310017 ; , s. 778-781
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Conference paper (peer-reviewed)abstract
- A compact dual-element antenna suitable for ultrawideband (UWB) MIMO operation is proposed in this work. The size of the antenna is 25 mm by 40 mm and it covers the lower UWB band of 3.15-5.15 GHz. Apart from the inherent wideband isolation obtained through the different angle and polarization characteristics in the radiation patterns of the individual elements, the gap between the two antenna elements is also utilized to enhance both the isolation and impedance bandwidths. Simulation and experimental results reveal that, within the band of interest, the achieved isolation is over 20 dB and the envelope correlation of the radiation patterns is below 0.1.
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