A Theory of Mutual Impedances and Multiple Reflections in an N-Element Array Environment (open access)

A Theory of Mutual Impedances and Multiple Reflections in an N-Element Array Environment

Abstract: A general theoretical approach is formulated to describe the complex electromagnetic environment of an N-element array. The theory reveals the element-to-element interactions and multiple reflections within the array. From the formulation, it is found that the interaction between an excited element and an open-circuited element can be viewed as the sum of terms describing all possible signal paths within the array environment which start from the radiating element and terminate on the element under observation. Within all paths except the most direct one, multiple reflections between subgroups of elements take place. The resulting solution is highly structured and recursive and is discussed in detail in the text. Illustrative examples are provided to facilitate understanding of these ideas.
Date: February 1985
Creator: Muth, Lorant A.
System: The UNT Digital Library
An Error Analysis for the Use of Presently Available Lunar Radio Flux Data in Broadbeam Antenna-System Measurements (open access)

An Error Analysis for the Use of Presently Available Lunar Radio Flux Data in Broadbeam Antenna-System Measurements

From introduction: Simple, precise expressions for lunar diameter, average brightness temperature, flux density, and shape factor are presented. An analysis of the relationship between these parameters and corresponding errors are included. For broadbeam (HPBW>d) antennas, results show that flux density and shape factor can be determined with errors less than 13 percent and 0.4 percent respectively at frequencies below 10 GHz. Extension of the analysis to higher frequencies is indicated.
Date: February 1984
Creator: Daywitt, William C.
System: The UNT Digital Library
Theory of Near-Field Phased Arrays for Electromagnetic Susceptibility Testing (open access)

Theory of Near-Field Phased Arrays for Electromagnetic Susceptibility Testing

From introduction: The feasibility of using a near-field array for electromagnetic susceptibility testing is studied. The basic objective is to control the element weightings such that a plane wave is generated within the test volume. The basic theory is developed for arbitrary array geometries, and numerical results are obtained for finite planar arrays. A general near-field array synthesis technique is developed, and the technique minimizes the mean square error in the test volume while constraining the array excitations. The constraint prevents large excitations and is useful in minimizing the fields outside the test volume. The basic idea looks promising, but some practical considerations, such as bandwidth and angular scanning limitations, require further theoretical and experimental investigation.
Date: February 1984
Creator: Hill, D. A.
System: The UNT Digital Library