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Wide-angle approximation, expressions for the radiated field, theĮffective height, and the terminal admittance are obtained. Variational expression for the terminal admittance is derived. The problem of radiation and reception of electromagnetic wavesĪssociated with a spherically capped biconical antenna having unequalīoth cones that comprise a bicone are excited symmetrically at theĪpices by a voltage source so that the only higher order modes are TM. The antenna allows an extremelyįlexible design of its characteristics at low cost, both requisites for Multiple input feed connectors in combination with an appropriateĪmplitude and phase shifting network. As with conventionalĪntenna arrays, adaptive pattern synthesis can also be realized by using Real-time space division multiple access (SDMA). Reception for communication in different angular directions for Multiple input feed connectors allows simple rotation of the antennaīeam by switching or, when independently operated, transmission and Several features of this multimode excitation are of interest. Propagation, which result in an angle-dependent far-field pattern. Independent TEM mode, higher order TE-modes are also allowed for

Set of higher order modes can be excited. ByĮnlarging the diameter of the coaxial feed to the biconical antenna, a In this paper, the biconicalĪntenna is modified for selective radiation in the azimuth direction. The biconical antenna is well known as an easy to build broad-bandĪntenna with omnidirectional radiation. It is shown that the use of the modified rule is more accurate when using a rectangle grid form. The obtained radiation patterns of a conductive plate using both the original rule and the modified one are compared with the electrodynamic analysis results. Additionally, the known equal area rule was modified for a rectangular grid form. The recommendations used for building a symmetrical wire-grid of those symmetrical antenna elements provided the most advantageous parameters of the grid and mesh settings and the wire radius, which are able to give quite accurate results with low computational cost. All results are shown to be in a good agreement. Moreover, the results are compared to those obtained using the finite difference time domain numerical method, as well as the measured ones. The results obtained using different grid and mesh settings are compared to those obtained analytically. These recommendations are used to calculate the characteristics of biconical and horn antennas at different frequencies.

The criteria and conditions for the use of wire-grid surface approximation from various sources are presented together with new recommendations for modeling symmetrical antenna structures using the wire-grid approximation. This paper focuses on the combination of the method of moments and the wire-grid approximation as an effective computational technique for modeling symmetrical antennas with low computational cost and accurate results.