A LOW COMPLEXITY DIRECTION FINDING SYSTEM BASED ON A SIX-PORT INTEGRATED MIMO ANTENNA SYSTEM

In this paper, a low complexity microwave based direction finding (DF) system is presented. The proposed system consists of a single six-port (SP) circuit integrated with a reconfigurable multiple-input-multiple-output (MIMO) antenna system. The SP circuit covers a wide frequency band (1.68-2.25 GHz). The SP circuit is also characterized for phase error compensation caused by the slight asymmetry of SP and power detectors. The reconfigurable MIMO antenna system used is a compact design and covers several well-known wireless standards in the frequency bands from 0.7 GHz to 3 GHz. The SP circuit is integrated with the reconfigurable MIMO antenna system to form a complete beam forming mode for second generation cognitive radio (CR) platforms. The proposed design is a complete integrated solution with DF capabilities for CR platforms. The design is suitable to be used in compact wireless handheld and mobile communication devices. The fabricated integrated system achieves ±16o accuracy in its direction of arrival estimates.