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Dynamic Control of the Input Impedance of Microstrip Elements Using Reactive Loads.

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Final rept. Jan-Sep 85,

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Great effort has been expended to develop MMIC modules for active aperture phased array radar antennas. The motivation for this work is to reduce the size, complexity and cost of phased arrays for space, airborne and ground based applications. Unfortunately, a large change in element input impedance occurs when the array is scanned. To isolate the module from this change, a ferrite circulator is inserted between the module and the antenna element. The insertion of the circulator is in direct conflict with the concept of MMIC and increases the module cost because it requires the introduction of circuit elements as a separate step in the production process. This final report is a theoretical and experimental evaluation of dynamically tuning patch radiators. The results of this study show that it is possible to change the input impedance of microstrip element over a wide range without affecting its resonant frequency or coplanar pattern by moving short circuits from one point to another. Having this capability may alleviate the need for the ferrite circulators, thus reducing the size, complexity and cost of phased array antennas. Keywords Dynamic impedance tuning Microstrip elements Phased arrays.

Subject Categories:

  • Active and Passive Radar Detection and Equipment
  • Electrical and Electronic Equipment

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