Patent ID: 7227493

Claim:
An apparatus for obtaining positional information relating to an object, the apparatus comprising: a transmitter for transmitting a probe signal towards the object, said transmitter comprising a transmitting element; a receiver for receiving, at a plurality of spaced apart locations, the probe signal as returned by the object, said receiver comprising a plurality of receiving elements forming an antenna array; and a detector, coupled to the receiver, for detecting the timing of the returned probe signals as received at one of the plurality of spaced apart locations relative to the timing of the returned probe signals as received at one or more other of the plurality of spaced apart locations; wherein angular position information for the object can be determined from said relative timing; the transmitting element and receiving elements are disposed within a single housing or on a common substrate and the receiving elements are spaced apart by distances that are the same order of magnitude as the wavelength λ of radiation that the apparatus is intended to transmit and receive; and wherein the size of each receiving element is less than 10λ, and is greater than λ/4, where λ is the wavelength of radiation that the apparatus is intended to transmit and receive.