A near field microwave scanning system includes a switched array of antenna elements forming an array surface, a scan surface substantially parallel to the array surface and separated by a distance less than about 1 wavelength of the measured frequency, and a processing engine for obtaining and processing near field data, without the use of an absorber. The disc drive also includes an actuator assembly rotatably attached to said base and a device for moving the actuator assembly. Preferably, the acylated fatty acid has a melting temperature above 40 C.