Abstract: A low cost microwave antenna. Microwaves are radiated from or collected by a thin layer radiating-collecting microwave guide section in which a dielectric slab is sandwiched between a metallic bottom plate and a metallic radiating-collecting cover plate. The cover plate contains a large number of slots spaced to produce outgoing or define incoming microwaves beams having directions determined: (1) by the directions of propagation of microwave radiation within the radiating-collecting microwave section and (2) by the frequency of the radiation. In a collection mode, a microwave lens focuses microwave radiation propagating in the waveguide section at focal locations which are dependent on the direction of propagation of the radiation in the waveguide. Alternatively, in a radiation mode, the lens converts microwave energy broadcast from said focal locations into parallel beams propagating in the radiating-collecting microwave guide section.

Abstract: A broadband spectrum analyzer for radio frequency and microwave signals. The signal to be analyzed modulates an optical laser beam through an electro-optic modulator. The resultant modulated beam thus comprises light at a frequency (carrier frequency) corresponding to the wavelength of the laser beam and frequencies close to the carrier frequency corresponding to the frequencies representing the modulating signal. The modulated beam is expanded to produce a beam with light traveling in a large number of directions within a narrow angle. The expanded beam illuminates the aperture of an etalon. The etalon functions as an optical filter passing only portions of the beam which enter the etalon at an angle such that the distance traveled by the light within the etalon equals an integral number of wavelengths. Thus, different frequencies pass through the etalon at different angles. The output from the etalon is collected by a video camera for display and interpretation.

Abstract: A camera system in which microwave radiation from objects in a field-of-view is collected by an antenna having beam directions which are a function of the beam frequency. The collected radiation is used to modulate an optical beam to impose upon the beam spectral components which are functions of the frequencies of the microwave radiation. The modulated beam is then analyzed by an optical spectrum analyzer to produce an image of objects in the field of view. In a simple embodiment of the invention a one dimensional image is produced. This one dimensional image can be converted to a two dimensional image by panning the camera system or mounting the camera on a moving platform. In this preferred embodiment the spectrum analyzer comprises an angle-frequency filter (preferably an etalon). The portion of the modulated beam passing through the etalon is directed in a number of directions, the directions being a function of the spectral components of the modulated beam.