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Constantine A. Balanis

Bio: Constantine A. Balanis is an academic researcher from Arizona State University. The author has contributed to research in topics: Antenna (radio) & Radiation pattern. The author has an hindex of 44, co-authored 402 publications receiving 30247 citations. Previous affiliations of Constantine A. Balanis include Arizona's Public Universities & Langley Research Center.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a simple general form for the Green's function is obtained by solving the boundary value problem separately for the TE and TM modes, and numerical results for pulse distortion on this type of microstrip are also included.
Abstract: The distortion of pulses due to dispersion and coupling on generalized planar microstrip is investigated. A simple, general form for the Green's function is obtained by solving the boundary value problem separately for the TE and TM modes. The mechanism of even/odd-mode distortion is discussed and numerical results are presented illustrating its effect. The design of structures with low even/odd-mode distortion is considered. Results for pulse distortion on this type of microstrip are also included. >

89 citations

Journal ArticleDOI
TL;DR: A technique to synthesize a new category of radar cross-section (RCS)-reduction metasurfaces is presented and by representing the generalized Snell–Descartes’ law of reflection in the form of array factor, it unifies the two most widely studied and well-established modern RCS-reduction methods.
Abstract: A technique to synthesize a new category of radar cross-section (RCS)-reduction metasurfaces is presented. The appealing feature of the proposed technique is that by representing the generalized Snell–Descartes’ law of reflection in the form of array factor, it unifies the two most widely studied and well-established modern RCS-reduction methods: checkerboard metasurfaces and gradient index metasurfaces. More importantly, it refines the concepts of both of these metasurfaces and overcomes numerous limitations associated with them. It can synthesize the RCS-reduction metasurfaces which can be placed along with almost any existing metasurface, without replacing the original metasurface that may be designed to serve a specific purpose, to reduce its RCS. The proposed technique is fundamentally based on scattering cancellation, and it is validated using artificial magnetic conductor technology for several configurations. Moreover, a phasor representation is developed and implemented for complex configurations to make the synthesis simpler and more insightful. Finally, to display the versatility of the proposed technique, an example of RCS-reduction metasurface has been synthesized and introduced to an existing high-gain metasurface ground plane available in the literature. This paper is confined to the conventional specular direction.

83 citations

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TL;DR: The vertical folded loop antenna, modeled as wire and printed radiating element mounted on a conducting box, simulating a cellular telephone with and without dielectric coating, is analyzed and meets the design requirements for existing and future mobile communication systems.
Abstract: The vertical folded loop antenna, modeled as wire and printed radiating element mounted on a conducting box, simulating a cellular telephone with and without dielectric coating, is analyzed. The finite-difference time-domain (FDTD) method is used to calculate radiation patterns and input impedance. The results are compared with measurements and with NEC data. Very good agreement is obtained in all cases. Parasitic loading is used to enhance the bandwidth of the printed element. The antenna meets the design requirements for existing and future mobile communication systems.

81 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used a mutual coupling matrix model to compensate mutual coupling in the beamforming of a uniform circular array, and compared the predictions with measurements, and verified with results from full-wave simulations.
Abstract: In a beamforming system, mutual coupling among the elements can significantly degrade the system performance. However, the mutual coupling effects can be compensated if an accurate model of mutual coupling is available. This paper utilizes a mutual coupling matrix model to compensate mutual coupling in the beamforming of a uniform circular array. In addition, a circular array of dipoles was built and measurements were performed. The predictions are compared with measurements, and verified with results from full-wave simulations

79 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed dual-frequency band checkerboard surfaces with 10-dB RCS reduction bandwidths of 61% and 24% by utilizing two dual-band EBG structures, while the surfaces maintain scattering in four quadrants.
Abstract: Radar cross section (RCS) of ground planes can be reduced along the principal planes by utilizing electromagnetic bandgap (EBG) structures. Checkerboard surfaces, combining two different EBG structures each on a quadrant of the same ground plane, can realize a wide frequency bandwidth for the 10-dB RCS reduction, because the scattered fields from checkerboard surfaces are redirected toward four quadrants. This communication proposes dual-frequency band checkerboard surfaces with 10-dB RCS reduction bandwidths of 61% and 24% by utilizing two dual-band EBG structures, while the surfaces maintain scattering in four quadrants. Bistatic and monostatic RCS of dualband checkerboard surfaces are simulated and the results are compared to the RCS of the corresponding perfect electric conductor (PEC) surface. Comparison of the monostatic RCS between the measurements and simulations, as a function of frequency, is considered for both TE z and TM z polarizations. A very good agreement is obtained between measurements and simulations.

78 citations


Cited by
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Journal ArticleDOI
TL;DR: The gains in multiuser systems are even more impressive, because such systems offer the possibility to transmit simultaneously to several users and the flexibility to select what users to schedule for reception at any given point in time.
Abstract: Multiple-input multiple-output (MIMO) technology is maturing and is being incorporated into emerging wireless broadband standards like long-term evolution (LTE) [1]. For example, the LTE standard allows for up to eight antenna ports at the base station. Basically, the more antennas the transmitter/receiver is equipped with, and the more degrees of freedom that the propagation channel can provide, the better the performance in terms of data rate or link reliability. More precisely, on a quasi static channel where a code word spans across only one time and frequency coherence interval, the reliability of a point-to-point MIMO link scales according to Prob(link outage) ` SNR-ntnr where nt and nr are the numbers of transmit and receive antennas, respectively, and signal-to-noise ratio is denoted by SNR. On a channel that varies rapidly as a function of time and frequency, and where circumstances permit coding across many channel coherence intervals, the achievable rate scales as min(nt, nr) log(1 + SNR). The gains in multiuser systems are even more impressive, because such systems offer the possibility to transmit simultaneously to several users and the flexibility to select what users to schedule for reception at any given point in time [2].

5,158 citations

Journal ArticleDOI
TL;DR: In this paper, a new type of metallic structure has been developed that is characterized by having high surface impedance, which is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements and distributed in a two-dimensional lattice.
Abstract: A new type of metallic electromagnetic structure has been developed that is characterized by having high surface impedance. Although it is made of continuous metal, and conducts dc currents, it does not conduct ac currents within a forbidden frequency band. Unlike normal conductors, this new surface does not support propagating surface waves, and its image currents are not phase reversed. The geometry is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements, and distributed in a two-dimensional lattice. The surface can be described using solid-state band theory concepts, even though the periodicity is much less than the free-space wavelength. This unique material is applicable to a variety of electromagnetic problems, including new kinds of low-profile antennas.

4,264 citations

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TL;DR: This paper presents a detailed study on recent advances and open research issues in WMNs, followed by discussing the critical factors influencing protocol design and exploring the state-of-the-art protocols for WMNs.

4,205 citations

Journal ArticleDOI
TL;DR: Very large MIMO as mentioned in this paper is a new research field both in communication theory, propagation, and electronics and represents a paradigm shift in the way of thinking both with regards to theory, systems and implementation.
Abstract: This paper surveys recent advances in the area of very large MIMO systems. With very large MIMO, we think of systems that use antenna arrays with an order of magnitude more elements than in systems being built today, say a hundred antennas or more. Very large MIMO entails an unprecedented number of antennas simultaneously serving a much smaller number of terminals. The disparity in number emerges as a desirable operating condition and a practical one as well. The number of terminals that can be simultaneously served is limited, not by the number of antennas, but rather by our inability to acquire channel-state information for an unlimited number of terminals. Larger numbers of terminals can always be accommodated by combining very large MIMO technology with conventional time- and frequency-division multiplexing via OFDM. Very large MIMO arrays is a new research field both in communication theory, propagation, and electronics and represents a paradigm shift in the way of thinking both with regards to theory, systems and implementation. The ultimate vision of very large MIMO systems is that the antenna array would consist of small active antenna units, plugged into an (optical) fieldbus.

2,717 citations

Journal ArticleDOI
Zhouyue Pi1, Farooq Khan1
TL;DR: This article introduces a millimeter-wave mobile broadband (MMB) system as a candidate next generation mobile communication system and demonstrates the feasibility for MMB to achieve gigabit-per-second data rates at a distance up to 1 km in an urban mobile environment.
Abstract: Almost all mobile communication systems today use spectrum in the range of 300 MHz-3 GHz. In this article, we reason why the wireless community should start looking at the 3-300 GHz spectrum for mobile broadband applications. We discuss propagation and device technology challenges associated with this band as well as its unique advantages for mobile communication. We introduce a millimeter-wave mobile broadband (MMB) system as a candidate next generation mobile communication system. We demonstrate the feasibility for MMB to achieve gigabit-per-second data rates at a distance up to 1 km in an urban mobile environment. A few key concepts in MMB network architecture such as the MMB base station grid, MMB interBS backhaul link, and a hybrid MMB + 4G system are described. We also discuss beamforming techniques and the frame structure of the MMB air interface.

2,487 citations