摘要:

A sleeve monopole is a conventional monopole antenna surrounded by a grounded metal tube (the sleeve). A relatively simple numeri-cal method is presented for obtaining a Fourier series representation of the current on both the monopole and its sleeve. The impedance and radiation pattern are also found. No limitation is placed on the radius of the sleeve. A special case of the numerical procedure yields the current, impedance, and pattern for an ordinary (sleeveless) monopole driven at any point along its length. Theoretical results derived here for the sleeve monopole agree well with published experimental data.

DOI:10.1049/ip-h-2.1988.0046

出版商:IEE    

年代:1988

数据来源: IET

摘要:

The problem of electromagnetic scattering, from a conducting cylinder of arbitrary cross-section covered by multiple layers of lossy dielectrics, is considered. The surface equivalence principle is used to reduce the problem to the solution of a set of coupled integral equations. The equations are then solved using the method of moments. Data are given for the surface currents, radiation patterns and scattering cross-sections for the case of TM incident waves. Computed results are in good agreement with exact and published data available.

DOI:10.1049/ip-h-2.1988.0047

出版商:IEE    

年代:1988

数据来源: IET

摘要:

It is useful to be able to predict both theE-field and monopole current time histories produced for a given pulse stimulating a radiating antenna, for both theoretical purposes and experimental measurements. Typical problems that arise in the remote measurements ofE–fields and mono-pole currents involve background radiation and spurious responses from reflecting objects, as well as detector malfunction. With prior knowledge of the expected waveform, which can be obtained very quickly, serious discrepancies can be easily identified, and the causes eliminated or the time windows adjusted if required.

DOI:10.1049/ip-h-2.1988.0048

出版商:IEE    

年代:1988

数据来源: IET

摘要:

An analytical Gaussian beam model for the radiation field of a corrugated horn antenna is presented. The model describes how the beam width and the location of the phase centre depend on the dimensions of the horn, and how they vary as a function of the distance from the horn aperture to the observation point. The model includes both the near-field and the far-field of the horn. These properties make the Gaussian feed model much better, for use in general work on reflector antennas, than the conventional cosnθ pattern. The Gaussian model is also used to define aperture-controlled and flareangle controlled horns, depending on whether the radiation patterns are frequency-sensitive or not.

DOI:10.1049/ip-h-2.1988.0049

出版商:IEE    

年代:1988

数据来源: IET

摘要:

An interactive iterative-synthesis technique is presented, which is of particular use for far-field patterns defined in terms of power only. The method is applied in general to three-dimensional array configurations composed of different element types, with the required far-field defined over large angular regions. Suggestions for extending the method to near-field, simultaneous multiparameter or constrained synthesis are also given. The description of the method is presented for three different conditions, depending on whether both the array amplitude and the phase or just the amplitude or the phase are variable. Examples of the method, applied to various practical synthesis problems, and comparisons to other techniques are also given.

DOI:10.1049/ip-h-2.1988.0050

出版商:IEE    

年代:1988

数据来源: IET

摘要:

An efficient and accurate method is presented for solving the problem of radiation from a flanged parallel plate waveguide fed with an input incident TE1mode. By matching the tangential fields, an integral equation with the aperture electric field as the unknown is obtained. The method of moments is used to solve the integral equation, with the chosen basis functions term by term satisfying the £-field edge condition explicitly and the H-field edge condition implicitly. The accuracy and efficiency of the method have been assessed by a study of the convergence pattern and by comparison with other available solutions. The comparison is extended to the case in which the input mode to the parallel-plate waveguide is the TEM.

DOI:10.1049/ip-h-2.1988.0051

出版商:IEE    

年代:1988

数据来源: IET

摘要:

The quasistatic characteristics of a parallel-plate waveguide with multiple slots of infinite extension in its upper plate are investigated in this paper. The analysis utilises the characteristic currents for the slots determined under the quasistatic approximation. The equivalent magnetic currents on the slots and the radiation pattern are determined when the array of slots is illuminated by a transverse electromagnetic wave incident in the waveguide, or by a transverse electric plane wave incident in the upper half-space. Analytic expressions, in the case of a single slot, are also given.

DOI:10.1049/ip-h-2.1988.0052

出版商:IEE    

年代:1988

数据来源: IET

摘要:

The admittance of a longitudinal slot in a ridge waveguide is calculated using the moment method. A modal expansion is used for Green's function inside the ridge waveguide. The results obtained with this method are compared with experimental data.

DOI:10.1049/ip-h-2.1988.0053

出版商:IEE    

年代:1988

数据来源: IET

摘要:

An approach for computing the input impedance of a general nonuniform transmission line is discussed. Results obtained therefrom are found to be in good agreement with existing analytic solutions for three selected geometrical configurations. The square-root tapered line is also studied. Design curves for the cosine-squared, parabolic and the square-root tapered lines are given.

DOI:10.1049/ip-h-2.1988.0054

出版商:IEE    

年代:1988

数据来源: IET

摘要:

Based on the solution of the Riccati equation, a broadband design of a microstrip exponentially tapered transmission line for matching two real impedances is found. An iterative procedure is used to yield the phase constant, leading to an accurate design that is used to match a helix to a coaxial cable. A comparison of theoretical and experimental results shows excellent agreement.

DOI:10.1049/ip-h-2.1988.0055

出版商:IEE    

年代:1988

数据来源: IET