Other

Thermotrex Corporation

Chris A Martin

Paul A Johnson

Ri-Chee Chou

Brett A Spivey

Britt Spivey

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. This new approach allows a larger instantaneous bandwidths to be analyzed than is possible with current systems, and allows a simple video camera to be used for observation of the spectrum of interest.

Electro-optic spectrum analyzer

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. The light passing through the etalon is focused on the aperture of a television camera to produce a one dimensional image. In another preferred embodiment an array of antennas and a corresponding number of optical modulators are used to produce a two dimensional real time image. The camera is capable of imaging objects through media such as wooden walls or fog, which are transparent to microwaves, but are opaque to visible light.

Growing community of inventors

San Diego, CA, United States of America

Chris A Martin