On primary incident wave models for pyramidal horn gain calculations

A few widely used primary incident wave models for pyramidal horn antenna analysis are compared on the basis of gain calculations. The analysis is based on edge-wave diffraction theory, as presented in a previous publication, with some modifications made to the underlying theory. It is shown that these models agree well for high-gain horns with small flare angles, but that the differences are more profound for lower gain horns, where the flare angles are larger. The accuracy of the various models are studied by comparing the results to actual measurements. The respective effects of amplitude and phase variation in the primary incident wave are also illustrated.     

Efficient full-wave modeling of patch antenna arrays with new single-layer capacitive feed probes

This paper introduces a new variation on the capacitive feed probe for patch antennas on thick substrates. It consists of a small circular probe-fed capacitor patch that is situated next to the resonant patch. This configuration can bring about significant savings in terms of manufacturing cost, but also lends itself to a very efficient full-wave analysis. As such, the main focus of this paper is a spectral-domain moment-method formulation, which was specifically developed for the analysis of large, but finite, arrays of these antenna elements. Entire-domain and subdomain basis functions are combined in an efficient way to minimize the computational requirements, most notably computer memory. It is shown that, for general antenna array configurations, memory savings of more than 1000 times can be achieved when compared with typical commercial software packages where only subdomain basis functions are used. A number of numerical and experimental results are also included in order to verify the spectral-domain moment-method formulation and to illustrate various applications of the new antenna element.     

New feeding mechanism for annular-ring microstrip antenna

A new feeding mechanism is presented that overcomes the usual problems associated with matching an annular-ring antenna. It consists of a probe-fed rectangular strip that is capacitively coupled to the annular ring. Numerical and experimental results for gain, bandwidth and radiation patterns are presented     

Horn antenna analysis as applied to the evaluation of thegain-transfer method

An important condition that has to be satisfied when implementing the gain-transfer method is that the fields in the test zone of the measurement facility should be as close to the plane wave as possible. In this paper, the effect of amplitude and phase deviation from a perfect plane wave, on gain measurements for microwave aperture antennas, conducted via the gain-transfer method, is determined and quantified. The pyramidal horn antenna is used as a basis for all calculations as it is the universal standard for microwave antenna gain measurements. Coupling, between the antenna being illuminated and the test zone fields, is evaluated by means of the reciprocity theorem. Test zone field variations are simulated and the effect thereof, on the predicted measured gain, is illustrated