Scheduled System Maintenance:
On May 6th, single article purchases and IEEE account management will be unavailable from 8:00 AM - 5:00 PM ET (12:00 - 21:00 UTC). We apologize for the inconvenience.
By Topic

Antennas and Propagation Magazine, IEEE

Issue 4 • Date Aug. 2004

Filter Results

Displaying Results 1 - 25 of 60
  • antenna-pattern correction for near-field-to-far field RCS transformation of 1D linear SAR measurements

    Publication Year: 2004 , Page(s): 177 - 183
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (789 KB) |  | HTML iconHTML  

    In a previous AMTA paper (B. E. Fischer, et al.), we presented a first-principles algorithm, called wavenumber migration (WM), for estimating a target's far-field RCS and/or far-field images from extreme near-field linear (one-dimensional) or planar (two-dimensional) SAR measurements, such as those collected for flight-line diagnostics of aircraft signatures. However, the algorithm assumes the radar antenna has a uniform, isotropic pattern for both transmitting and receiving. In this paper, we describe a modification to the (one-dimensional) linear SAR wavenumber migration algorithm that compensates for nonuniform antenna-pattern effects. We also introduce two variants to the algorithm that eliminate certain computational steps and lead to more efficient implementations. The effectiveness of the pattern compensation is demonstrated for all three versions of the algorithm in both the RCS and the image domains using simulated data from arrays of simple point scatterers. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Intellectual property and patent abstracts

    Publication Year: 2004 , Page(s): 149 - 156
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (755 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • In Memoriam: George Hubert Hagn

    Publication Year: 2004 , Page(s): 77 - 80
    Save to Project icon | Request Permissions | PDF file iconPDF (668 KB) |  | HTML iconHTML  
    Freely Available from IEEE
  • Predicting directivity of standard-gain pyramidal-horn antennas

    Publication Year: 2004 , Page(s): 93 - 98
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (699 KB) |  | HTML iconHTML  

    Improvements proposed over the years in the edge-diffraction model for a pyramidal-horn antenna have been extended to include the three-dimensional nature of the pyramidal horn in evaluating the edge-diffraction fields. The theoretical model was compared with measured results, measured over a number of years at an international standards laboratory for frequencies ranging from 2.45 GHz to 18 GHz, with measurement uncertainties between ±0.04 dB and ±0.1 dB. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the eigenvalue distribution of smart-antenna arrays in wireless communication systems

    Publication Year: 2004 , Page(s): 158 - 167
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1621 KB) |  | HTML iconHTML  

    The recent development of communication theory and smart-antenna techniques such as space-time coding (STC), which exchange efficiency for complexity, has intensified the interest in a general theory of multiple-antenna communication. These techniques use parallel channels to increase the capacity of wireless systems. The parallel channels are formed either in a natural way, due to radiowave propagation (receiving diversity, RD, RAKE), or in an artificial way, due to appropriate pre-processing and coding (transmitting diversity, TD, STC), or in both ways (multiple-input multiple-output, MIMO, systems, STC, BLAST). The demand for ubiquitous, heterogeneous, and sophisticated wireless systems has led to the need for a better understanding of fundamental issues in space-time communication theory, and their implications for the design of reliable, high-bandwidth and high-speed wireless communications. The authors discuss the issue of eigenvalue distribution for antenna arrays. The present article provides an approach that should be useful in simulations, analysis, and design of smart-antenna wireless systems. The results show that this parameter of the spatial channel has an important rcHe to play in analyzing the performance of antenna arrays in wireless systems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • President's Message

    Publication Year: 2004 , Page(s): 7 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Hear Ye 4! Hear Ye 4!

    Publication Year: 2004 , Page(s): 185
    Save to Project icon | Request Permissions | PDF file iconPDF (420 KB)  
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Education Column

    Publication Year: 2004 , Page(s): 136 - 139
    Save to Project icon | Request Permissions | PDF file iconPDF (626 KB) |  | HTML iconHTML  
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Light at the end of a nanohole

    Publication Year: 2004 , Page(s): 115 - 116
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (526 KB) |  | HTML iconHTML  

    Over the last few years the extraordinary transmission of EM waves through sub-wavelength apertures in an opaque sheet has been demonstrated experimentally and explained theoretically. To add another twist to the field, investigators are now marrying the unusual properties of negative-index materials with enhanced transmission through small apertures. In A. Alu et al. (2004) presented at the Monterey conference, it discussed how (at least theoretically) layers of metamaterials sandwiching a sheet with a small hole might also enhance transmission without any periodic structure, e.g., grooves, on the sheet. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Compact antenna test range without reflector edge treatment and RF anechoic chamber

    Publication Year: 2004 , Page(s): 27 - 37
    Cited by:  Papers (3)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1079 KB) |  | HTML iconHTML  

    There are several types of CATRs (compact antenna test ranges) used in antenna-pattern measurements. An offset reflector is generally used to generate the quiet zone of a CATR. Serrated edges, rolled edges, or R-cards are generally chosen along the reflector's edge to reduce the edge-diffraction field inside the quiet zone of the CATR. In order to reduce stray signals from the environment, a high-quality RF anechoic chamber is required for a CATR. In this paper, a new type of CATR, without either a reflector edge treatment or an RF anechoic chamber, is developed. A commercially available DBS (direct-broadcast satellite) reflector antenna, without edge treatment, is used as the reflector antenna of the CATR to generate the quiet zone of the antenna test range. In order to improve the quiet zone's performance, the fields due to feed spillover, edge diffractions, and other stray signals are gated out by the ITDAMS (impulse time-domain antenna measurement system). The RF interference in the environment can also be reduced by time synchronization and pulse integration of the impulse time-domain antenna measurement system. In order to verify the capabilities of the proposed CATR, three kinds of antennas (a low-directivity horn antenna, a high-directivity 60 cm direct-broadcast satellite reflector antenna, and a 25 cm Ka-band Cassegrain LMDS - local microwave distribution system - antenna) were measured by the proposed CATR. The antenna-pattern results agreed quite well with those of a near-field range and a far-field range. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Review of narrowband impedance-matching limitations

    Publication Year: 2004 , Page(s): 88 - 90
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB) |  | HTML iconHTML  

    Many antennas can be characterized by their radiation Q (the ratio of reactance to radiation resistance). A classic problem is determining the maximum possible bandwidth, constrained by the maximum permissible reflection magnitude, and the number of tuned circuits in the impedance-matching circuit. This paper presents a review on theoretical limitations of narrowband impedance matching. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • SEMCAD DASY 4 iSAR Phantoms Dipoles

    Publication Year: 2004 , Page(s): 81
    Save to Project icon | Request Permissions | PDF file iconPDF (518 KB)  
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Self esteem and placebos

    Publication Year: 2004 , Page(s): 148
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (453 KB) |  | HTML iconHTML  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A report on Japanese development of antennas: from the Yagi-Uda antenna to self-complementary antennas

    Publication Year: 2004 , Page(s): 47 - 60
    Cited by:  Papers (19)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1131 KB) |  | HTML iconHTML  

    The self-complementary antenna structure was originated and its constant-impedance property was discovered by the author in 1948. He pursued investigations of this type of antenna for many years, and he attained many extensions of the principle of self-complementarity, from the simplest planar structure to various other cases. In parallel with these studies, extensive developmental investigations of extremely broadband antennas have been carried out in Japan, based on this principle. This article succinctly describes a long history of these studies on self-complementary antennas, including the background of its origination. In connection with the extremely broadband property of this type of antenna, the non-constant-impedance property of incorrectly arranged log-periodic antennas is clearly shown, based on the results of experiments. This experimental fact indicates that the log-periodic shape in an antenna's structure does not guarantee a broadband property for the antenna. Most of experimental details and all of the theoretical treatments are omitted from this article. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Meetings and Symposia

    Publication Year: 2004 , Page(s): 119 - 121
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (593 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High performance EM simulation and optimization and electronic design automation

    Publication Year: 2004 , Page(s): 2
    Save to Project icon | Request Permissions | PDF file iconPDF (515 KB)  
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Poet's Corner

    Publication Year: 2004 , Page(s): 122
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (430 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Target-aspect-dependent RCS: the effect on assumed beam angle

    Publication Year: 2004 , Page(s): 75 - 78
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (485 KB)  

    Traffic speed enforcement is becoming more reliant on automated speed-detection devices, particularly the use of photographically linked slant radar devices. We have conducted an analysis of whether target-aspect-dependent radar cross section (RCS) could have an effect on the accuracy of speed measurements. It was found that there is the potential for a 2.5% error (for a radar aligned at 22° to the road, with a -3 dB beamwidth of 5°) in the speed measured by the radar devices. This is because of the interference between the RCS and the radar beam pattern, if only the main lobe is considered. There are cases, however, when the interference between the RCS and the radar beam patterns are such that the strongest return occurs in the first sidelobe. In these cases, the potential speed error is about 7%. This would be unlikely to occur in practice, however, because of the inverse fourth-power relationship with range. We have not included the details of RCS sidelobe returns in the analysis. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • AMTA Corner

    Publication Year: 2004 , Page(s): 176 - 177
    Save to Project icon | Request Permissions | PDF file iconPDF (527 KB) |  | HTML iconHTML  
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Academic and professional resources for student-led technology ventures

    Publication Year: 2004 , Page(s): 125 - 131
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (855 KB) |  | HTML iconHTML  

    Student researchers face daunting challenges when attempting to take a developed technology and use it as the foundation for an emerging enterprise. Engineering students typically lack an overall understanding of the commercialization process associated with academic research. Moreover, the resources required by the student span several disciplines including law, business, and engineering. Only recently have engineering programs included entrepreneurial courses covering the basic concepts that are essential for technology-business development. At the University of Michigan, such courses include an MBA business-plan development sequence that an increasing number of engineering graduate students elect, an undergraduate engineering course in business-plan development, and a patent-law class specifically for engineering students. Academic resources such as these significantly increase the likelihood of stimulating student entrepreneurial activity as well as successful commercialization of university research. However, these resources alone are typically insufficient. Professional resources, such as those offered by the Technology Management Office and the Zell-Lurie Entrepreneurial Institute at Michigan, provide business development support, ranging from one-on-one business development counseling to grant programs for emerging business from university research. In this paper, we discuss the complete process of commercializing academic research. We address critical academic and professional resources in the process of business development and how they have fostered entrepreneurial activity, which has contributed to successful commercialization of engineering research at the University of Michigan. Several of the challenges faced by the student entrepreneur have been addressed by these resources at Michigan, while others still require further development that is well underway. Here we report on these activities, while aspiring to foster inspiration for the development of entrepreneurial resources at engineering institutions across the country. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reviews and Abstracts

    Publication Year: 2004 , Page(s): 101 - 103
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (571 KB) |  | HTML iconHTML  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An active surface for large reflector antennas

    Publication Year: 2004 , Page(s): 11 - 19
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1239 KB) |  | HTML iconHTML  

    We present a solution adopted for the Noto antenna (Sicily) in order to overcome the degradation of antenna efficiency due to the gravitational deformation of the structure of large antennas. This new setup allows a substantial increase in the operating frequency, and eliminates the dependence of the antenna efficiency on elevation. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The SUMMA graduate fellowships in advanced electromagnetics

    Publication Year: 2004 , Page(s): 113
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Chapter News

    Publication Year: 2004 , Page(s): 68 - 72
    Save to Project icon | Request Permissions | PDF file iconPDF (782 KB) |  | HTML iconHTML  
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The analysis of wideband spiral antennas using modal decomposition

    Publication Year: 2004 , Page(s): 20 - 26
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (783 KB) |  | HTML iconHTML  

    This paper discusses modal decomposition and its application to wideband antenna measurements. Applying network analysis, a simple finite Fourier series decomposes measured far-field patterns into characteristic modes to determine the power in each mode. The technique is useful for identifying measurement inaccuracies and errors due to antenna design or manufacturing problems. The analysis can be applied to a general class of antennas that radiate a set of characteristic modes; however, this paper demonstrates the concept with wideband, multi-mode spiral antenna measurements. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

The IEEE Antennas and Propagation Magazine covers all areas relating to antenna theory, design, and practice.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Mahta Moghaddam