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The objective of this study was to design a receive only, vertically-polarized marine X-Band radar antenna with the following specifications: Frequency of operation: 9.4 GHz Horizontal beamwidth: 1.0 degrees Vertical beamwidth: 20 degrees Maximum horizontal aperture: 10 feet Gain: 30 dB Horizontal sidelobes: less than 30 dB Bandwidth: 1.5 percent or 150 MHz The design study was to yield an antenna...
The usefulness of broadband impedance matching to increase the bandwidth of a microstrip patch antenna is illustrated using three different antenna configurations. Measured data for a patch antenna was incorporated into commercial CAD software to design a matching network. Design limitations are also discussed. Practical design examples and experimental results are given which clearly demonstrate...
A new model for analyzing discontinuities in MIC devices is being proposed. The technique is based on the boundary element method. An MIC device with an arbitrarily shaped discontinuity can be treated as a one-dimensional problem. Two numerical examples are given for checking the validity of the model.
A rigorous analysis of an aperture-coupled stacked microstrip antenna is described. Developed from a coupled integral equation set employing spectral-domain Green's functions, the analysis includes all coupling, radiation and surface-wave effects. Optimization of the patch dimensions yielded VSWR bandwidths of greater than 20%. Theoretical and measured responses exhibited excellent agreement.
As a general numerical technique for solving electromagnetic problems, the finite element method[FEM] appears to compete favorably with other numerical methods. As an example, when used for solving circuit discontinuities and EM scattering, it can handle arbitrarily shaped discontinuities, including anisotropic waveguide components such as ferrite devices. Various forms of FEM have been used in EM...
A theoretical and experimental study of the patch antenna input impedance variation with feedline width is presented. Measured results were compared with some of the currently available numerical models. A limitation of these numerical models was established and the techniques will be modified to overcome this shortcoming.
An antenna pattern measurement system has been developed which operates over the frequency range 1 to 12.4 GHz. The system makes pattern measurements and tests gain, beamwidths, and sidelobe levels under far-field conditions. Measurements using a Hewlett-Packard 8410A vector network analyzer as the receiver are managed by an in-house-developed software package for use on an IBM PC-AT microcomputer.
A circular array receiving antenna is highly attractive for radio direction finding because of its geometrically circular symmetry and, thereby, the periodicity of its electromagnetic features, such as mutual coupling between elements of the array, when its beam is scanned electronically through 360 degrees. In radio direction finding systems, the elements of an array are considered to be sensors...
In this paper, an enhanced precision “Thru-Reflect-Line” (TRL) calibration technique is presented which allows highly accurate, de-embedded measurements to be made for a microstrip line-fed patch antenna with an arbitrary feed line characteristic impedance. This technique provides tremendous design flexibility and reduces the phase uncertainty to about 1 degree for the low dielectric constant material...
In this paper the bandwidth performance of a broadband adaptive array is investigated. We carry out simulations based on a linear array with K elements, where each element is followed by a tapped delay-line with L taps. It is shown that by using multi-frequency constraints with the method of Minimum Variance Distortionless Response (MVDR), we get a plateau in the frequency response (relative bandwidth...
The full-wave analysis of finite large printed dipole arrays is performed by the Conjugate Gradient - FFT method with full wave discrete image technique. The CG-FFT method has the merits of saving computer memory (O(N)) and computing time (O(4N(l + log2(N)))), compared with the conventional Moment Methods (O(N2) and O(N3), respectively). This makes the CG-FFT method very suitable for efficient analysis...
In this paper we have described the evolution that is taking place in antenna engineering. Antennas are now being interfaced with active devices, thereby making them integrated antennas; and, as well, they are about to be interfaced to digital logic, which in turn will lead to intelligent antennas. The art of antenna engineering being expanded by the requirement for algorithmic development, digital...
The dispersive absorbing boundary condition (DBC) developed in [1] for microstrip component analysis, a case where dispersion is week, is now applied to a strongly dispersive case which occurs in conductor waveguides. The absorbing quality of the DBC is found to be much superior to that of the absorbing boundary conditions that are currently used for waveguide component analysis. Due to the significant...
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