Elevation/Azimuth Propagation Angle Measurements Using Five-Port Wave Correlators

The five-port wave correlator in microstrip technology consists of a ring with 5 arms and three diode power detectors. The ratio of two waves (radio frequency and local oscillator) is determined as a linear combination of the power levels measured at the five -port's outputs. The advantages of using five-port are its low-cost, its less sensibility to phase and amplitude imbalances and its operation in a wide frequency band. We present in this paper a system based on five-port wave correlators, which measure the detection of arrival (DOA) in azimuth and in elevation plan of radio frequency signals. The parallel receivers operating at 2.4 GHz consist of 8 five-ports and a planar antenna array of 8 quasi-Yagi antenna elements. The DOA is estimated by measuring the phase difference of the signals picked up by the elements in the array and by using the MUSIC (multiple signal classification) algorithm. The phase difference is determined using the five-port technique. The simulation and measurement results show that the signals are accurately estimated with one error of 2deg.