Modern Antenna Design Using Mode Analysis Techniques

Abstract

Abstract-In this paper, the modal theory of antennas is re-visited, believing that it brings invaluable information towards facilitating the design of multi-feed multi-band antennas. First, some subtle changes are proposed to enhance the applicability of the theory. Next, using some efficient computational techniques, the proposed formulations are shown to predict, to a very high accuracy, the input impedance of any antenna under study. This greatly simplifies the antenna problem and focuses design efforts on finding the appropriate complex resonance frequency to cover a required band. Finding the appropriate feed location is then a matter of extracting the corresponding impedance map for this antenna through simple field manipulations.

Single-Layer Differential-Fed Wideband Metasurface Antenna Using Characteristic Mode Analysis

“…However, since (11) is derived based on the virtual probes, it neglects the inductances contributed by the physical probes. Furthermore, to ensure the antenna presents an open circuit at dc, an equivalent dc capacitance C dc should be introduced [22]. Taking into account of the probe inductances and the dc capacitance, the diferential impendence in (11) can be rewritten as…”

Analysis of Offset Antennas in Radio Telescopes

“…The main advantage of the offset design is that the aperture blockage can be reduced since the feed, subreflector and the support structure are moved away from the path of the incoming signals to the primary reflector. Hence, the loss of the antenna, particularly spillover loss and also cross polarization can be significantly reduced [21]. Fig.…”