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Amplitude Modulation Van Atta Array

IP.com Disclosure Number: IPCOM000096553D
Original Publication Date: 1963-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Niebuhr, KE: AUTHOR

Abstract

This device achieves the amplitude modulation of a Van Atta array by the insertion of variable phase shifters in half of the transmission lines interconnecting the array.

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Amplitude Modulation Van Atta Array

This device achieves the amplitude modulation of a Van Atta array by the insertion of variable phase shifters in half of the transmission lines interconnecting the array.

The conventional Van Atta array comprises a series of antenna elements 1... 4 connected by equal electrical length transmission lines a. . . d to an identical, conjugate, series of antenna elements (1'... 4'). The array has the property of reflecting an incident plane wave back into the direction of incidence, regardless of the incidence of the incoming wave on the array.

Insertion of variable phase shifters, capable of altering the electrical length of a transmission line by 180 electrical degrees, into half of the transmission lines,
e. g., lines b and d, allows amplitude modulation of the reflected wave from the array. This is achieved by adjusting the phase shifters so that half of the transmission lines have an electrical length which differs from that of the other half by 180 degrees. In such a case, phase shifters so that half of the transmission lines have an electrical length which differs from that of the other half by 180 degrees. In such a case, the reflective properties of the Van Atta array are completely destroyed. As no coherent phase addition occurs in the array, the reflected beam is of minimum, zero, amplitude. When the phase shifters are returned to their normal condition, all the transmission lines again become of equal length and the arra...