Various collocated circular loop antennas: theory, analysis and design

Collocated circular loops form an important class of antenna structures with potential for use in direction-finding and many other applications. In this paper, a general formulation for analyzing a set of arbitrarily oriented circular loops is first presented. The formulation is then used to analyze various collocated loop configurations. In particular, collocated orthogonal and skewed loops are discussed. Two new types of antennas, the butterfly-loop and the direct-coupled concentric half-loop are also discussed. For all the cases, the theoretical results of the analysis were in close agreement with the measured results.