摘要:

Planar antenna arrays have been developed at 140 GHz using twin-dipole elements. The initial systems have been fabricated using a hybrid approach with beam lead Schottky GaAs diodes mounted on quartz substrates. Heterodyne measurements of subelement sensitivities have yielded DSB noise temperatures of 12,000 K. Subsequently implementation of completely monolithic systems has been demonstrated using SIS technology.

ISSN:0272-6343    

DOI:10.1080/02726348308915184

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The use of printed antenna techniques at millimetre wavelengths to create planar linear travelling wave antennas is commonly considered to be inhibited by the microstrip feeder loss and the alternate use of low loss dielectric feeders is thus attractive. In this investigation an additional source of unwanted loss is considered and a complete assessment, more favourable to microstrip, emerges. The fields of an insular guide antenna feeder are computed by a mode matching method to provide accurate data for the guide attenuation and also the launcher radiation loss when the insular guide is connected to a conventional rectangular metal waveguide using a horn launcher transition. This latter analysis is based both on a chopped surface wave distribution method and an alternative variational method. Similar loss data is computed for microstrip antenna feeders using existing theories and some experimental data presented. A comparison of total unwanted losses for both types of feeders establishes that microstrip is advantageous for feeder lengths up to about 20 wavelengths long, the precise condition for equality depending on many other factors which are discussed. If however the feeders are assumed to be fully integrated with an electrically compatible guide structure in the receiver or transmitter to remove the source of launcher radiation loss, insular guide is distinctly advantageous, thus highlighting the need for new technological developments in integrated millimetre linear antenna systems.

ISSN:0272-6343    

DOI:10.1080/02726348308915185

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Efficiencies of elementary integrated-circuit feed antennas are calculated considering both the substrate and the optics. Calculations are made for dielectric constants of 4, for fused-quartz substrates, and 12, for silicon and gallium-arsenide substrates. The effect of substrate lenses, anti-reflection coatings, and adjustable backshorts is also considered. A feed efficiency of 60% is predicted for a slot on a substrate and substrate lens with dielectric constant 12, and 63% for a dipole on a substrate with dielectric constant 12 and lens of dielectric constant 4.

ISSN:0272-6343    

DOI:10.1080/02726348308915186

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The radiation efficiency of printed circuit antennas due to surface-wave effects is optimized to 100% for lossless materials. This is attained with a magnetic superstrate layer on a dielectric substrate. A combination of substrate-superstrate thickness and material parameters results in the elimination of surface wave modes and, therefore, radiation efficiency optimization. When antennas are printed on a grounded substrate with moderate values of dielectric constant, elimination of surface wave modes and, therefore, 100% radiation efficiency due to material effects can be obtained only with the addition of a magnetic superstrate layer if radiation resistance is to be kept at a useful level.

ISSN:0272-6343    

DOI:10.1080/02726348308915187

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

In this paper the problem of the parallel-plate waveguide with a ferrite substrate, having a semi-infinite upper plate and being excited by a TE mode is considered. The direction of the static(d.c.) magnetic field is taken to be parallel to the edge of the terminated upper plate. The problem is formulated on the basis of the Wiener-Hopf technique and ends up in a Wiener-Hopf integral equation with a non-symmetric kernel function, in contrast to the symmetric kernels of all isotropic problems formulated by the same technique. Factorization is now accomplished by a modification of the typical procedure, suitable to the present, non-syrmetric kernel. Expressions for the reflection and coupling coefficients of the modes are given and the far field is computed by application of appropriate asymptotic techniques. The numerical results reveal the definite possibility of controlling most of the operational characteristics of the structure by simply varying the intensity of the magnetizing field.

ISSN:0272-6343    

DOI:10.1080/02726348308915188

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A suspended patch antenna excited by an inverted microstrip line is analyzed by a spectral domain technique followed by an equivalent waveguide-to-cavity model. Accuracy of the results is confirmed by comparison with experimental data.

ISSN:0272-6343    

DOI:10.1080/02726348308915189

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

This work was supported by Grants NAG-1-163 and NAG-1-279 between the National Aeronautics and Space Administration, Langley Research Center, Hampton, VA, and the University of Massachusetts, Amherst, HA 01003.

ISSN:0272-6343    

DOI:10.1080/02726348308915190

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The fundamental solution for printed circuit antennas on cylindrical substrates is presented in this paper. Exact expressions are obtained for the electromagnetic field both inside the substrate as well as the surrounding free space produced by an arbitrarily oriented printed circuit dipole. Asymptotic results are derived for a cylindrical thin substrate whose diameter is large compared to wavelength.

ISSN:0272-6343    

DOI:10.1080/02726348308915191

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

It has been demonstrated that a microstrip antenna excited in a non-degenerate resonant mode has a driving point impedance which can be modeled as a resonant parallel R-L-C circuit in series with the an inductor. The latter is an inductance which can be associated with the feeding probe or microstrip line feed of the antenna. This paper investigates the variation with feed location of this inductive component both experimentally and by a full modal expansion of the field using the “cavity model”. The results demonstrate that the simple, feed position-independent formula for this inductive component is inadequate for certain applications involving loaded microstrip elements. The results also show that the cavity model can predict the variation of feed inductance with feed location reasonably well except near the edge of the patch. The physical mechanism for the variation of this inductive component as well as the physical reason why the cavity model overestimates this parameter with feeds near the edge are presented. A rigorous model of a coaxial feed is studied in which the primary exciting field is assumed to be an incident TEM wave in the cable. It is found that for elements thin enough for the cavity model to be applicable, use of the probe current distribution alone as the primary source yields impedances which differ only slightly from those provided by the rigorous model. However, other results are obtained which indicate the limits of such a simple feed model as the element thickness increases.

ISSN:0272-6343    

DOI:10.1080/02726348308915192

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The increasing use of microstrip antenna arrays calls for a rigorous analysis of the coupling between antenna elements. In this paper a full wave analysis is presented to rigorously formulate the resonance of a coupled two circular disk resonator using the Vector Hankel Transform, together with the translational properties of the cylindrical harmonics. The matched asymptotic expansion approach is then used to asymptotically evaluate the resonant frequencies of the structure. The Galerkin moment method and a perturbative approach which can also be used to calculate the resonant frequencies are reviewed. The results obtained using these methods are compared with those of the matched asymptotic expansion approach developed in this paper. It is shown that the asymptotic matching approach provides significant saving in computation time and furthermore supplies simpler expressions for the resonant frequencies as compared to the Galerkin method and the perturbative approach.

ISSN:0272-6343    

DOI:10.1080/02726348308915193

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor