Patent ID: 7132979

Claim:
A method of calibrating a switchable antenna array having a radiation pattern, said antenna array including at least two vertical columns each having at least two antenna elements arranged one above the other, the antenna elements having inputs, said array of the type further including a beam forming network including a Butler matrix connected to the antenna element inputs, the Butler matrix having inputs and outputs and having phase control elements connected to the inputs thereof, the Butler matrix outputs being connected to feed the antenna element inputs in at least one of said columns, the beam forming network producing a different phase relationship between the plural antenna elements depending on which of plural inputs of said Butler matrix are connected to a common feed, in order to achieve a desired beam direction in the azimuth direction, the method comprising: feeding at least two of said inputs of the beam forming network simultaneously via a common feed cable arrangement, receiving and processing signals produced by fewer probes associated with a vertical column than there are antenna elements of said vertical column; and at least in part in response to said received and processed signals, calibrating said antenna array to provide antenna radiation pattern adjustment in azimuthal direction for intermediate azimuthal angles, including trimming the phase control elements to cause the characteristic phase differences associated with the Butler Matrix inputs to intersect at a common calibration point, thereby producing radiation pattern intermediate lobes providing further different azimuth beam directions, such that the radiation pattern lobes produced when at least two inputs are connected can be added with predetermined desired phase.