United States of America As Represented by the Secretary of the Air Force

Earth Sounding International

Van Etten, Paul

Brown, Russell D.

Paul Van Etten

Michael C Wicks

John V McNamara

Russell D Brown

A Mono-Blade Antenna is disclosed which operates over many octaves of bandwidth. Electromagnetic waveforms may be transmitted and received with multi-decade bandwidth using: a metal ground plane, a Mono-Blade Antenna element fixed above the ground plane, and a coaxial transmission line feed which is connected to the antenna element and the ground plane. The antenna element has three sections: a throat, a mouth, and a radial tip. The throat is comparatively narrow and serves as the element feed point by being connected to the center conductor of the coaxial cable. The mouth is the mid-section of the antenna element, which is the widest section of the blade. The tip of the blade is formed by an arc of approximately constant radius, which results in a low voltage standing wave ratio.

Mono-blade phase dispersionless antenna

A multi-octave bandwidth antenna is disclosed which radiates with variable polarizations using: a metal ground plane, first and second blade antenna elements, first and second coaxial transmission line feeds, and a 180.degree. hybrid coupler. The two blade antenna elements are fixed above the metal ground plane in proximity with each other, and fed respectively by the central conductors of the first and second coaxial transmission line feeds. The 180.degree. hybrid coupler has a sum and difference port to control the polarization of waveforms of the antenna.

Polarization diverse phase dispersionless broadband antenna

Range-Doppler ambiguity is eliminated from an ultra-wideband radar system by transmitting an ultra-wideband chirped pulse towards a moving target, and mixing it with the doppler-shifted chirped pulse which is received as a target echo return signal. Multioctave radar tracing systems can potentiality track stealth aircraft without ambiguity since pulses containing many frequencies can defeat narrow-band radar absorbing material coatings. The unambiguous range-doppler signal processing method mixes the chirped pulse to yield an instantaneous Doppler frequency (which indicates target velocity) and a rate of change in the instantaneous Doppler frequency (which indicates target acceleration).

Unambiguous range-doppler processing method and system

An earth probing system uses deep penetration of electromagnetic waves into soil and other media. Advantage is taken of the lower attenuation of radar waves in soil by frequencies of about three megahertz or less. Bursts of electromagnetic energy of various frequencies in this range are consecutively transmitted. The transmitting antenna is continuously tuned, so as to maintain resonance during each burst, allowing large circulating currents and high power output. In a receiving antenna system, a dual antenna arrangement is providing for obtaining improved reception. A corresponding dual antenna circuit employs 'spatial notch filtering', automatic adjustment of antenna gain-frequency variations, as well as compensation for transmitter gain variation. The system may be implemented in a totally analog, totally digital, or hybrid manner. Preferably, a signal processing method detects and digitally samples signals reflected from subsurface layers and buried objects. The invention provides means for removing system distortions and interfering signals, for compensating for aliasing errors and frequency-dependent antenna gain and phase variations, and for avoiding masking errors introduced by strong reflections.

System and method for earth probing with deep subsurface penetration

A signal processing circuit which operates on a spread spectrum received signal to compress it into a waveform of sufficient amplitude to allow detection by conventional means. The received signal is filtered and split onto two paths, each path being mixed with an upper or lower single sideband created by an oscillator and modulator combination. The output of each mixer is filtered and mixed together in a third mixer, the resultant output of which is fed through a narrow bandpass filter to a conventional signal detector.

Detection of angular modulated electromagnetic signals

A system for performing real time quantization and analog/digital conversion of an analog waveform operating with analog input signals over one gigahertz bandwidth is realized by utilizing a CRT type device in which the electron beam is deflected by the analog input waveform. The deflected electron beam strikes a fast phosphor screen and an externally positioned target consisting of light sensitive elements arranged in a discrete pattern detects and quantizes the signal. The output of the detectors feed an encoder resulting in a binary digital output waveform. The device accepts both unipolar and bipolar video waveform and has parallel output channels such that further circuitry to be employed can operate with reduced bandwidths.

High speed real time quantizer and analog/digital converter

The high-power, short-pulse array is a self-contained radiating oscillator system which radiates a high peak-power pulse of radio frequency energy. The radiated pulses contain only a few cycles of RF and hence it is a short-pulse emitter. The device contains a chain or a series of loops which radiate in phase and each loop has a spark gap. The spark gaps are sequentially fired. The radiated waveform can be a single pulse of RF or a train of RF pulses. The device requires only a high voltage power supply for operation.

Plural loop spark gap RF pulse radiation converter

A polarization radar method and system employs polarization discrimination to obtain target-to-clutter enhancement. The polarization of the radar is rotated at very fast rates. The polarization is rotated at least 360.degree. during one pulse and discrimination is obtained with a single pulse operation. In the system, the receiver is tuned to a frequency that was not radiated by the radar's transmitting antenna.

Polarization radar method and system

A real time data rate quantizer and analog-to-digital converter system employs an electron beam which is deflected by an analog input waveform. The deflected electron beam strikes a mosaic target in which electron beam sensitive elements detect and quantize the signal. The outputs of the detectors feed an encoder resulting in a binary digital output waveform.

Growing community of inventors

Clinton, NY, United States of America

Paul Van Etten