A log-periodic dipole array system employs a structure for the transmitter and the receiver designed in a way such that they compensate for the non-linear characteristics of each other to realize linear phase characteristics as a pair. The optical bus can include a substrate and input optical waveguides formed on the substrate. An image sensor unit may measure, collect, sense andor detect the aerial image in situthat is, the aerial image at the wafer plane produced, in part, by a product-type photomask andor by associated lithographic equipment used, or to be used, to manufacture of integrated circuits.