ANTENNA SYSTEM

PURPOSE:To improve the accuracy of phase measurement by providing pickup antennas in a plurality of directions and dividing an element into a plurality of sub-arrays in corresponding to the direction, and then, measuring the element and a reference element with the pickup antennas. CONSTITUTION:Pickup antennas 5a and 5b are respectively provided in thetaa and thetab direction. Firstly, by changing the phase of a phase shifter 2, the resultant electric field of phased array antennas is measured by means of the antenna 5a and the phases of one element in a sub-array 6a and reference element 7 are found. Since the elements of the array 6a contribute substantially at the same level to the resultant electric field vector in the thetaa direction, the phase values are highly accurate. Similarly, the phases of the element in the sub-array 6b and the element 7 are measured by means of the antenna 5b by changing the phase of the phase shifter 2. Then, the difference in phase of each sub-array is found on all elements 1 on the basis of the phase of the element 7. Therefore, the phase can be found more accurately by increasing the contribution of the resultant electric field vector to all elements in such way.