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IEEE Transactions on Antennas and Propagation

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Displaying Results 1 - 25 of 28
• Analysis of electromagnetic scattering from dielectrically coated conducting cylinders using a multifilament current model

Publication Year: 1988, Page(s):1602 - 1607
Cited by:  Papers (24)
| | PDF (566 KB)

A method of moments solution is presented for the problem of transverse magnetic scattering from dielectrically coated conducting cylinders. The solution uses fictitious filamentary electric sources of yet unknown currents to simulate both the field scattered by the cylinder and the field inside the dielectric coating. The simulated fields obey the boundary conditions, namely, the continuity of th... View full abstract»

• Mutual coupling and sidelobe tapers in phase-only antenna synthesis for linear and planar arrays

Publication Year: 1988, Page(s):1624 - 1629
Cited by:  Papers (2)  |  Patents (1)
| | PDF (508 KB)

A method of obtaining the lowest possible peak sidelobe levels, given a specified sidelobe envelope, by phase-only variation of the generator phases is presented. A generalization of earlier work by the authors, this technique involves the optimization of a piecewise differentiable objective function using the method of steepest descent to obtain desired generator phases, given prescribed excitati... View full abstract»

• A quick way to approximate a Sommerfeld-Weyl-type integral [antenna far-field radiation]

Publication Year: 1988, Page(s):1654 - 1657
Cited by:  Papers (25)
| | PDF (336 KB)

A method to evaluate the Sommerfeld-Weyl-type integral rapidly in the far field is reviewed. With such a method, one can perform back-of-the-envelope' derivations for the far-field expressions of Sommerfeld-Weyl-type integrals. First, the stationary-phase point of the integrand is identified. Closed-form integrals are then identified that can be used to integrate the rapidly varying part of the i... View full abstract»

• Spectral domain analysis of a coupled slot antenna

Publication Year: 1988, Page(s):1620 - 1624
Cited by:  Papers (12)
| | PDF (400 KB)

The characteristics of a coupled slot resonator suitable for novel design of an integrated planar antenna are analyzed. The analysis is based on the spectral domain immittance matrix approach, and all the wave phenomena associated with the structure are incorporated. The resonant frequencies in the even and odd resonance modes are evaluated from the numerical solution of the characteristic equatio... View full abstract»

• An experimental radome panel evaluation

Publication Year: 1988, Page(s):1566 - 1570
Cited by:  Papers (1)
| | PDF (364 KB)

Modern antenna radomes are made of materials that tend to shed water to minimize their RF attenuation when wet. The microwave performance of these materials has been studied experimentally. Radome attenuation was measured as a function of frequency, rain rate, rain incidence angle, RF incidence angle, and polarization. The tests were performed on (1) new, clean radome panels, (2) used, dirty radom... View full abstract»

• Approximate analytic continuation of the Rayleigh series [radar cross-section]

Publication Year: 1988, Page(s):1652 - 1654
Cited by:  Papers (1)
| | PDF (252 KB)

Pade approximants are used to continue approximately the Rayleigh series for the radar cross section (RCS) of the sphere beyond its radius of convergence. Numerical studies show that accurate results for the RCS can be obtained to ka ~2.2 if many series terms are available. Since this is rarely, if ever, the case, it is further demonstrated that even with only four nonzero terms available... View full abstract»

• A conjugate gradient procedure for the analysis of planar conductors with alternating patch and aperture formulations [EM scattering]

Publication Year: 1988, Page(s):1616 - 1620
Cited by:  Papers (7)
| | PDF (424 KB)

The formulation of an electromagnetic scattering problem by an operator equation can be done in different ways leading to different rates of convergence when the conjugate gradient algorithm is used. The convergence can tend to slow down at certain stages, depending on the formulation used. Thus, whenever the error tends to level off in one formulation, it is advisable to switch to another one. To... View full abstract»

• The clamshell problem'-interpolation of shaped reflectors and other smooth surfaces

Publication Year: 1988, Page(s):1560 - 1565
Cited by:  Papers (4)
| | PDF (492 KB)

An interpolation method for shaped reflector antennas and similar smooth surfaces is developed using cubic spline interpolants in a parametric representation. Ordinary one-dimensional splines are combined in tensor products to give a two-dimensional interpolant for each cartesian component of points of the surface. The two independent variables are the polar coordinates of rays traced from an aper... View full abstract»

• Scattering from dipoles loaded with diodes

Publication Year: 1988, Page(s):1649 - 1651
Cited by:  Papers (13)
| | PDF (268 KB)

The problem of scattering from dipoles arbitrarily loaded with passive and active diodes is solved by the method of moments. Results are presented for the tumble average scattering radar cross section of dipoles loaded with p-i-n diodes and negative resistance diodes such as tunnel and Gunn diodes. Single as well as multiple loadings are considered View full abstract»

• Theoretical and experimental investigation of the elliptical annular ring antenna

Publication Year: 1988, Page(s):1526 - 1530
Cited by:  Papers (11)
| | PDF (384 KB)

Analysis of a confocal elliptical annular ring microstrip antenna is carried out using the generalized transmission line model. It is found that a circularly polarized wave can be obtained over a wider frequency range than for conventional structures. It is also found that unlike the elliptical patch the resonant frequency for the odd mode is lower than that of the even mode. Therefore, for a left... View full abstract»

• Comparison between computed and measured bandwidth of quarter-wave microstrip radiators

Publication Year: 1988, Page(s):1615 - 1616
Cited by:  Papers (90)
| | PDF (132 KB)

A simple theory based on a cavity model is used to analyze a quarter-wavelength flat element, without a dielectric substrate, which is connected to the ground plane in one of its sides by a metallic wall. The bandwidth of the element is computed from this model. Very good agreement is obtained between the computed and the measured bandwidth for elements in the S-band View full abstract»

• Antenna array design for covariance-based direction-finding methods

Publication Year: 1988, Page(s):1537 - 1544
Cited by:  Papers (2)
| | PDF (740 KB)

Angle-of-arrival estimates based on the analysis of a spatial covariance matrix are particularly vulnerable to error in the presence of coherent signal interference. When this condition exists, the wave interference field is statistically nonstationary, and estimation techniques that are based upon an assumption of stationarity tend to produce poor results. A method is proposed for the design of a... View full abstract»

• An experimental adaptive array to suppress weak interfering signals

Publication Year: 1988, Page(s):1551 - 1559
Cited by:  Papers (5)
| | PDF (712 KB)

An experimental adaptive antenna system to suppress weak interfering signals is described. It is a sidelobe canceller with two auxiliary elements. Modified feedback loops are used to control the array weights. The received signals are simulated in hardware for parameter control. Digital processing is used for algorithm implementation and performance evaluation. The experimental results are present... View full abstract»

• Shaped-pattern synthesis using pure real distributions

Publication Year: 1988, Page(s):1645 - 1649
Cited by:  Papers (33)  |  Patents (1)
| | PDF (380 KB)

Shaped patterns can be produced by properly excited equispaced linear arrays. An earlier synthesis procedure, which accomplishes this with control ripple in the shaped region and controlled sidelobe levels elsewhere, results in array distributions that are generally complex. It is shown here that if the shaped pattern is symmetric and has 2M filled nulls, there are 2M complex s... View full abstract»

• Realizable feed-element patterns and optimum aperture efficiency in multibeam antenna systems

Publication Year: 1988, Page(s):1637 - 1641
Cited by:  Papers (17)  |  Patents (2)
| | PDF (464 KB)

The results of an earlier paper by Y. Rahmat-Samii et al. (ibid., vol.AP-29, pp.961-3, 1981), regarding realizable patterns from feed elements that are part of an array that feeds a reflector antenna, are extended. The earlier paper used a cosq θ model for the element radiation pattern, whereas here a parametric study is performed, using a model that assumes a central beam of cos<... View full abstract»

• V-conical antenna

Publication Year: 1988, Page(s):1519 - 1525
Cited by:  Papers (18)
| | PDF (412 KB)

A new angular antenna called the V-conical antenna was investigated. The characteristics of the antenna are frequency-independent, and the electromagnetic fields are pure spherical waves (transverse electromagnetic mode) even in the near region. The theoretical analysis makes use of conformal mapping. Closed-form solutions for the fields, currents, and characteristic parameters are obtained. The f... View full abstract»

• A new prediction method for tropospheric scintillation on Earth-space paths

Publication Year: 1988, Page(s):1608 - 1614
Cited by:  Papers (68)  |  Patents (101)
| | PDF (556 KB)

A method of predicting scintillation fading occurring on Earth-space paths is proposed that is based on the data obtained from a low-elevation 14/11 GHz wave propagation experiment at Yamaguchi, Japan. This model includes parameters representing meteorological conditions that have not been covered in existing models and can be applied to broad regions with varying climates. The prediction accuracy... View full abstract»

• Element gain pattern prediction for finite arrays of V-dipole antennas over ground plane

Publication Year: 1988, Page(s):1629 - 1633
Cited by:  Papers (4)
| | PDF (368 KB)

The element gain pattern for finite phased arrays of dual-polarized crossed V-dipole antennas over ground plane is addressed. The method of moments is used to predict the center-element gain pattern. An experimental, 19-element, passively terminated planar array is described, and center-element gain pattern measurements are presented. The theoretical results are in good agreement with measurements View full abstract»

• An anisotropic lens for transitioning plane waves between media of different permittivities

Publication Year: 1988, Page(s):1571 - 1579
| | PDF (464 KB)

A particularly simple geometry is considered in which an inhomogeneous and anisotropic lens is specified for the transitioning of plane waves between media of different permittivities. The permittivities of the regions outside of the lens can be constant, but the permittivity of the lens region depends on position. Results are presented for a plane wave in the second medium propagating normally to... View full abstract»

• A design procedure for slot arrays fed by single-ridge waveguide

Publication Year: 1988, Page(s):1531 - 1536
Cited by:  Papers (30)  |  Patents (1)
| | PDF (348 KB)

R.S. Elliott's (1983) design procedure for arrays of longitudinal slots in one broad wall of each rectangular waveguide is extended to the case in which the waveguides have ridges in the opposite broad walls. External mutual coupling has been taken into account. A two-be-eight array was constructed and tested, and the results validate the theory. Ridging is significant because it permits E View full abstract»

• Performance of probe-fed microstrip-patch element phased arrays

Publication Year: 1988, Page(s):1501 - 1509
Cited by:  Papers (47)
| | PDF (632 KB)

The performance trends for large phased arrays with probe-fed microstrip-patch elements are discussed, with primary consideration given to single-probe (unbalanced) feed for rectangular grid arrays with rectangular patch geometry. The effects of substrate thickness and permittivity, patch dimensions, and element spacing are examined. Pronounced surface- and leaky-wave effects that tend to limit th... View full abstract»

• The application of a biquadratic programming method to phase only optimization of antenna arrays

Publication Year: 1988, Page(s):1545 - 1550
Cited by:  Papers (19)
| | PDF (436 KB)

Antenna array optimization by a biquadratic programming method is formulated with variable-phase (analog and digital) and constant amplitude excitation. The method can optimize an antenna performance index expressible as a ratio of Hermitian quadratic forms. Power gain optimization and least-squares pattern synthesis with a specified gain are illustrated. Linear, planar, and circular arrays with d... View full abstract»

• An X-band experimental model of a millimeter-wave interinjection-locked phased array system

Publication Year: 1988, Page(s):1641 - 1645
Cited by:  Papers (9)
| | PDF (348 KB)

An interinjection-locked 10 GHz model of a millimeter-wave phased-array system has been built and tested. It has been successfully demonstrated that this novel technique can be used to control limited-scan phased-array antennas. A beam shift of ±5° has been achieved with only one phase shifter in a four-oscillator system. Adaptability to monolithic fabrication and a reduction in the num... View full abstract»

• A template for shaped-beam satellite antenna patterns

Publication Year: 1988, Page(s):1633 - 1637
Cited by:  Papers (4)
| | PDF (448 KB)

A modified template is proposed for shaped-beam satellite antenna patterns for use in orbit-planning studies of a fixed satellite service. Based on a previously discussed simple model, the template now includes the effects of beam scanning, aperture blockage, and surface errors. It is found to agree well with the measured data on current satellites and is a reasonable upper bound specification for... View full abstract»

• Extended integral equation formulation for scattering problems from a cylindrical scatterer

Publication Year: 1988, Page(s):1580 - 1586
Cited by:  Papers (11)
| | PDF (520 KB)

An extended integral equation is developed for electromagnetic scattering from a perfectly conducting cylinder and a dielectric cylinder. The conventional surface integral equations cannot yield unique solutions when the wavenumber of the electromagnetic wave is equal to an eigenwavenumber of the system. Several methods to overcome this difficulty have been presented, but each method includes some... View full abstract»

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

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Editor-in-Chief                                             Danilo Erricolo