By Topic

Antennas and Propagation, IEEE Transactions on

Issue 3 • Date March 1999

Filter Results

Displaying Results 1 - 22 of 22
  • Guest editorial: Special issue on phased arrays

    Page(s): 413 - 415
    Save to Project icon | Request Permissions | PDF file iconPDF (40 KB)  
    Freely Available from IEEE
  • Analysis of finite arrays-a new approach

    Page(s): 555 - 565
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (276 KB)  

    A novel method for the analysis of finite arrays is presented. The method is based on a global array concept where the array problem (for single-mode elements) is reduced to a solution of a single Fredholm integral equation of the second kind. This formulation offers several types of solutions (not all explored yet) with illuminating results. The approximate solution of this integral equation, for example, yields finite array characteristics in terms of equivalent infinite array scattering parameters and mutual admittances. The method is general, i.e., applicable to any element-type and periodic array geometry. Presently, the method applies to single-mode elements (one unknown per element), however, it can be extended to a multimode analysis View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Anomalous edge effects in finite arrays

    Page(s): 549 - 554
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (92 KB)  

    The regular oscillations in scan impedance (normalized by the infinite array values) that occur across a finite array are uniquely altered in two special cases based on computer simulations of finite-by-infinite arrays. First, dipoles with groundplane at broadside in the E-plane, exhibit a slow modulation of the usual oscillations; the period of the modulation varies with dipole radius. For all other cases, the results are insensitive to radius. Second, for a dipole array and lattice spacing and H-plane scan angle that allow a grating lobe to appear at -90° the oscillations disappear, except at the rear edge. These phenomena give some indications of the behavior of the pseudotraveling waves in scan impedance View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Voltage-controlled ferroelectric lens phased arrays

    Page(s): 458 - 468
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (388 KB)  

    A new concept for phased arrays is proposed using a voltage-controlled ferroelectric lens. The ferroelectric lens concept uniquely incorporates bulk phase shifting-the array does not contain individual phase shifters-using ferroelectric material. This will reduce the number of phase shifters from (n×m) to (n+m), where n is the number of columns and m is the number of rows in a phased array. The number of phase shifter drivers and phase shifter controls is also significantly reduced by using row-column beam steering. Thus, the ferroelectric lens concept can potentially lead to low-cost phased arrays. This paper presents the ferroelectric lens concept, theoretical analysis and design, and experimental results. The results indicate that the ferroelectric lens concept is viable and sound. Various phased-array configurations using ferroelectric lens are included. A discussion on ferroelectric materials is included along with information on a US Department of Defense program to improve ferroelectric materials View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multifunction wide-band array design

    Page(s): 425 - 431
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    High-performance active arrays operating over C, X, and Ku-band have been demonstrated using newly developed designs of wide-band radiating elements and wide-band monolithic microwave integrated circuits (MMICs). The advanced shared aperture program (ASAP) explored the development of wide-band multifunction arrays capable of simultaneous and time interleaved radar, electronic warfare, and communications functions. Two iterations of radiating element and transmit/receive (T/R) module design were completed during this program. The radiating aperture design approach, overall array concepts, and current design technology and performance are summarized View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Near-field alignment of phased-array antennas

    Page(s): 584 - 591
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    This paper describes the algorithms and equipment used to apply near-field scanning techniques to the phase alignment of phased-array antennas. This procedure achieves a level of precision not previously available. The electronic scanning property of the antenna is used to bring different sections of the antenna spectrum within range of the near-field scanning process. These partial spectra are then merged to define the entire spectrum of the antenna. This process provides the resolution needed to determine the excitation at individual elements by the inverse Fourier transformation operation. The process described here has been used in the production of a very large number of phased-array antennas currently in service View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Genetic algorithms in the design and optimization of antenna array patterns

    Page(s): 506 - 510
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    This paper demonstrates the application of genetic algorithms (GAs) in array pattern synthesis. GAs have the ability to escape from local minima and maxima and are ideally suited for problems where the number of variables is very high. We present three examples: two for linear arrays and one involving linear and planar arrays View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Perturbation formulas for microstrip patch arrays and elements

    Page(s): 536 - 541
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    One-term perturbation formulas are derived to characterize periodic microstrip arrays with nonuniform planar distributions of dielectric and magnetic materials. Analogous results are also obtained for single-patch elements. The formulas are generally applicable to other types of antennas View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Beamformer architectures for active phased-array radar antennas

    Page(s): 432 - 442
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    In active phased-array antennas, the transmit and receive functions are distributed at the antenna aperture using transmit and receive (T/R) modules. The use of T/R modules provides a significant improvement in antenna performance and flexibility in the choice of array architectures. We present a review of various beamformer architectures for active phased-array antennas. This review is limited to corporate-fed active phased-array antennas for radar applications. Beamformer architectures for narrow and wide bandwidth arrays, including the choice of applying an amplitude taper in the T/R module or beamformer network are discussed. Beamformer architectures that increase antenna reliability are also presented View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Novel low-cost beam-steering techniques using microstrip patch antenna arrays fed by dielectric image lines

    Page(s): 453 - 457
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    This paper presents novel low-cost beam-steering techniques using microstrip patch antenna arrays fed by dielectric image lines (DILs). Two approaches are designed and used. The first, DILs without reflector plate, are used for feeding microstrip patch antenna arrays. Antenna array radiation beams are scanned when the operating frequency sweeps. The second, a dielectric image line with a movable reflector plate (DILWRP), is developed. The beam direction of the antenna array is controlled and steered by changing the perturbation distance between DIL and movable reflector plate at a given operating frequency. Both types of patch antenna array structures are simple, low cost, easily fabricated, stable, and reliable. Eight-element patch antenna arrays fed by DIL and DILWRP have been designed, fabricated, and tested. Experiments show good performance and results. Measurement results of scanning angles agree well with theoretical predictions View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A phase-control approach for a large-element coherent microwave power uplink system

    Page(s): 487 - 495
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (476 KB)  

    Signal combining efficiencies of 98% have been achieved on low-Earth orbiting (LEO) debris with phase-locking of time-overlapped radar pulses from a two-element phased-array consisting of two 34-m beam waveguide steerable paraboloid antennas separated by 204 m. The uplink arraying at 7.19 GHz has been achieved for tracks from about 10° elevation at signal rise to 4° elevation at signal set under varying weather conditions (e.g., hail failing on one antenna). The typical root mean square (RMS) phase error for two coherent 100-μs 50-Hz 5-kW peak pulses reflected from LEO debris with signal-to-noise ratio (SNR) >23 dB is less than 4°. The phase-control system design, methods of calibration, and details of the design control table of phasing error contributors are presented and discussed. Based upon the measured performance, we predict that transmitting antennas for the Deep Space Network (DSN) could be coherently arrayed for up to hours at a time given static phase error calibrations on exo-atmospheric debris. Applications for this technique include low-cost implementation of high-power microwave transmitters for deep-space communication and radars for exploration of other planets and as part of a defense against comets and asteroids View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Design of unequally spaced arrays for performance improvement

    Page(s): 511 - 523
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    Classical antenna array synthesis techniques such as Fourier, Dolph-Chebyshev and Taylor synthesis efficiently obtain array current distributions for equally spaced arrays that generate a desired far-field radiation pattern function or keep important parameters like beamwidth and sidelobe level within prescribed performance bounds. However, the concept of optimization of the field pattern (e.g., by decreasing sidelobes or beamwidth) of an given equally spaced array realization by altering its element spacings still represents a challenging problem having considerable practical advantages. These include reduction in size, weight, and number of elements of the array. This paper describes a new approach to synthesis of unequally spaced arrays utilizing a simple inversion algorithm to obtain the element spacings from prescribed far-zone electric field and current distribution, or current distributions from prescribed far-zone electric field and element spacings View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An edge-slotted waveguide array with dual-plane monopulse

    Page(s): 474 - 481
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (420 KB)  

    Edge-slotted row waveguides have often been stacked to form light-weight planar arrays. With phase-shifter scanning in elevation and 360° mechanical rotation in azimuth, a large surveillance volume may be covered at relatively low cost. For applications that require accurate target location, elevation monopulse is readily available by means of an appropriate beamformer. However, past attempts to obtain monopulse in the plane of the slotted waveguides have not met with much success. While the alternative has been to employ run length estimation (beam-splitting based on a sequence of target returns), accuracy limitations and the required elevation dwell time render this solution inadequate for certain applications. Now, however, a new waveguide array configuration has been developed that provides dual-plane monopulse and still retains one-dimensional phase scanning along with the advantages of low cost and light weight. A full-scale Ku-band array employing this new architecture has been built and tested to demonstrate practical utility View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Near-field to near/far-field transformation for arbitrary near-field geometry utilizing an equivalent electric current and MoM

    Page(s): 566 - 573
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    Presented here is a method for computing near- and far-field patterns of an antenna from its near-field measurements taken over an arbitrarily shaped geometry. This method utilizes near-field data to determine an equivalent electric current source over a fictitious surface which encompasses the antenna. This electric current, once determined, can be used to ascertain the near and the far field. This method demonstrates the concept of analytic continuity, i.e., once the value of the electric field is known for one region in space, from a theoretical perspective, its value for any other region can be extrapolated. It is shown that the equivalent electric current produces the correct fields in the regions in front of the antenna regardless of the geometry over which the near-field measurements are made. In this approach, the measured data need not satisfy the Nyquist sampling criteria. An electric field integral equation is developed to relate the near field to the equivalent electric current. A moment method procedure is employed to solve the integral equation by transforming it into a matrix equation. A least-squares solution via singular value decomposition is used to solve the matrix equation. Computations with both synthetic and experimental data, where the near field of several antenna configurations are measured over various geometrical surfaces, illustrate the accuracy of this method View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Practical failure compensation in active phased arrays

    Page(s): 524 - 535
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB)  

    A practical failure compensation technique for active phased arrays is presented. It is suitable for real-time applications and is applicable to any distribution of the failures across the array. It is independent of the external signal environment and is capable of achieving substantial performance improvement across broad selectable angular sectors at the expense of some additional performance degradation in other less important sectors View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The IRIDIUM main mission antenna concept

    Page(s): 416 - 424
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    The design of a novel phase array panel that provides the L-band satellite to ground links for the IRIDIUM global communications system is presented. Key components and aspects of this phase array antenna are discussed including the beamforming architecture, radiated intermodulation products, the patch radiators, and the T/R module. The strategy for minimizing DC power consumption over a large range of multicarrier RF output power is described. Finally, test results showing compliant array operation are summarized View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • CAD of waveguide array antennas based on "Filter" concepts

    Page(s): 542 - 548
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (200 KB)  

    In this paper, an alternative approach for the design of open-ended waveguide array antennas is presented. The approach is based on microwave filter concepts. The exploitation of this alternative viewpoint has been made possible by the availability of a very efficient computer-aided design (CAD) tool which is based on a full-wave modal analysis technique. In this paper, we first outline the technique for the efficient analysis of open-ended waveguide array antennas. Using the software developed and following the alternative design approach, two different application examples are then shown, indicating how the alternative viewpoint introduced gives indeed significant additional degrees of freedom. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Receiver array calibration using disparate sources

    Page(s): 496 - 505
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (884 KB)  

    We present a new array calibration procedure for over-the-horizon (OTH) radar, using disparate sources. Unlike previous array calibration methods, which require a specific type or class of sources for calibrating the array, the method we propose can use combinations of single-mode, multimode, and near-field sources; each source with either known or unknown DOAs (directions-of-arrival). Multidimensional MUSIC is exploited for time-invariant DOA sources, while single-snapshot techniques are used for sources that have time-varying DOAs. A nonlinear separable least-squares solution to the array calibration problem is used to estimate the array coupling matrix and sensor positions. Simulation results indicate that good estimates are obtained for the unknown parameters and further the array sidelobe levels and bearing errors are significantly reduced when these estimated parameters are used in array processing. The algorithm performance was also compared with the Cramer-Rao lower bound and found to be statistically efficient View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Scanning and impedance properties of TEM horn arrays for transient radiation

    Page(s): 469 - 473
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    A general concept for ultrawide-band array design using interconnected transverse electromagnetic (TEM) horns is described. At high frequencies (wavelength small compared to unit cell dimensions), the mutual coupling between elements is small and, consequently, the input impedance depends only on the lattice dimensions and not on either scan angle or frequency. At low frequencies (wavelength large compared to unit cell dimensions), the mutual coupling is purposefully made large, by interconnecting the elements to maximize the low-frequency performance. This paper presents the results of analyses using a periodic hybrid finite-element approach to calculate input impedance and scanning performance of generic TEM horn arrays. The limiting case, the planar bicone, is shown to have the frequency-independent property of a self-complementary antenna, making it a useful case for establishing the effects of feed region geometry. Although it radiates bidirectionally, it has the interesting property that its broadside-scan frequency response in the array environment is absolutely flat up to the grating lobe onset limit. A TEM horn array is more unidirectional, but as a consequence suffers both oscillatory variations in the input impedance with frequency and increased limits on minimum achievable rise time View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Phaseless bi-polar planar near-field measurements and diagnostics of array antennas

    Page(s): 574 - 583
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (760 KB)  

    Antenna near-field measurements typically require very accurate measurement of the near-field phase. There are applications where an accurate phase measurement may not be practically achievable. Phaseless measurements are beginning to emerge as an alternative microwave antenna measurements technique when phase cannot be directly measured. There are many important aspects for successful implementation of a phaseless measurement algorithm. This paper presents appropriate phaseless measurement requirements and a phase retrieval algorithm tailored for the bi-polar planar near-field antenna measurement technique. Two amplitude measurements and a squared amplitude optimal sampling interpolation method are integrated with an iterative Fourier procedure to first retrieve the phase information and then construct both the far-field pattern and diagnostic characteristics of the antenna under test. In order to critically examine the methodologies developed in this paper, phaseless measurement results for two different array antennas are presented and compared to results obtained when the near-field amplitude and phase are directly measured View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Beam-shape correction in deployable phased arrays

    Page(s): 482 - 486
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    Deployable phased-array antennas-antennas that are receiving great attention-have a major problem in that they possess the possibility of an incomplete deployment and antenna shape distortion. These effects cause a displacement of the element antenna positions that results in deviation of the phase distribution on the antenna aperture, eventually causing antenna beam deflection. We have investigated how to correct this beam deflection by observing the phased-array antenna from certain directions. There are cases when more than one observation point is necessary to carry out the proposed method depending on the extent of the antenna shape distortion and the number of the points is consulted. This correction method makes it possible to correct the deflection of the main beam and also to determine the displacement of relative element positions View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimum design of feed structures for high G/T passive and active antenna arrays

    Page(s): 443 - 452
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (228 KB)  

    In this work, noise analysis of parallel feed structures is presented. Signal and noise behavior of the feed structures are signified by the newly introduced concepts of “coherent” and “incoherent” impedance match of power-combining structures. It is also shown that a feed structure can be redesigned for low-noise operation without affecting the radiation characteristics. Optimum design of parallel feed structures for low-noise operation is explained. Also an optimum use of active elements in such structures is investigated to have a low overall noise temperature of the antenna array with minimum number of active elements. In the analysis, a new method is introduced where a “noise-equivalent line length” (NELL) is defined. This definition, which unifies the contribution of noise from different array elements, is used in the design of a parallel feed structure and as an active circuit replacement criteria in passive arrays View full abstract»

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

Aims & Scope

IEEE Transactions on Antennas and Propagation includes theoretical and experimental advances in antennas.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief                                                 Kwok W. Leung