Henning F. Harmuth

Bio: Henning F. Harmuth is an academic researcher from Geophysical Survey. The author has contributed to research in topics: Signal & Dipole antenna. The author has an hindex of 9, co-authored 10 publications receiving 312 citations.

Frequency independent shielded loop antenna

Abstract: An antenna is disclosed that is especially useful for radiating and receiving non-sinusoidal electromagnetic waves. The antenna is an efficient and distortion-free radiator of electromagnetic pulses that do not use a sinusoidal carrier. The antenna's size is independent of frequency and the antenna, therefore, can be of small size relative to the wavelength of the radiated electromagnetic waves. When used for reception of electromagnetic wave energy, the antenna performs with low distortion. The basic concept underlying the invention is the modification of the Hertzian electric dipole into an antenna structure that can carry large currents without requiring a large driving voltage. Antennas for the transmission or reception of sinusoidal waves achieve that goal by employing resonant structures. The invention achieves the same result by changing the Hertzian electric dipole into a loop that forms a Hertzian magnetic dipole and preventing the undesirable magnetic dipole radiation by shields of conducting and absorbing materials.

Sliding correlator for nanosecond pulses

Abstract: A digital sliding correlator having means for producing a series of time-shifted stored copies of a digital character, means responsive to said shifted, stored copies of the character for multiplying said shifted, stored copies by the input signal or the sign-inverted counterpart of the input signal, a first set of integrators and a second set of integrators, means for supplying to the first set of integrators first portions of said multiplied signals and for supplying to said second set of integrators second portions of said multiplied signals, and means for combining the outputs of said integrators.

Range information from signal distortions

Abstract: An electromagnetic signal having originally the time variation of a rectangular pulse is transmitted into a medium with conductivity σ. It is distorted by the medium to a signal f(σ,d,t) if it traveled the distance d from a transmitter to a scattering or reflecting object and the same distance d back to the transmitter. The time variation f(σ,d,t) of the distorted signal can be calculated for any conductivity σ and distance d. Using the conductivity σ known from previous measurements, the returned, distorted signal f(t) is compared with computed distorted signals f(σ,d,t) for various distances d. The computed signal f(σ,d,t) that is most similar to the actually received signal f(t) determines the distance d to the scattering or reflecting object. The comparison between the computed, distorted signals and the actually received signal is done by cross-correlations. The peak amplitude or the energy of the received signal becomes unimportant if cross-correlation is used, which means the physical size or radar cross-section of the scattering or reflecting object becomes unimportant.

Selective reception of carrier-free radar signals with large relative bandwidth

Abstract: A method for generating a sequence of short radar pulses and a method plus apparatus for detecting those same short pulses when backscattered, even though they are heavily distorted by a target and have additive noise and unwanted signals superimposed on them. The method applies to pulses of long or short duration, including durations of 1 nanoseconds (1 ns) or less. The pulses are transmitted without the fine structure marking of a sinusoidal wave carrier, but organized into a coarse structure that results from incorporating them within a highly unconventional type of character, wherein a plurality of positive-going and negative-going pulses are transmitted such that each pulse is spaced apart from its neighbors. Each pulse is short, so the return signal is highly distorted. The sequence of positive-going and negative-going pulses are organized into a pattern of non-contiguous pulses that constitute a new type of "character", which may be thought of as a "spaced-apart-character". This "spaced-apart-character" is organized into a large coarse structure marking, so that a) the total transmitted energy is large, b) a receiver can selectively distinguish the wanted return signal from noise and unwanted signals, and c) reflections from targets longer than L=Δtc/2 are rejected.

Large relative bandwidth radar

Abstract: A method of detecting an object that may be coated with material for preventing or attenuating reflections of incident electromagnetic waves is disclosed in which pulses of electromagnetic wave energy are generated with a large relative bandwidth in the band from about 0.1 GHz to about 12.0 GHz. Preferably, the generated pulses have a pulse duration in the range from 0.1 nanosecond to 1 nanosecond. Those pulses of electromagnetic wave energy are directed toward the object and reflections of those pulses of electromagnetic wave energy which are incident on the object are detected by receiving apparatus. The method enables coated objects to be differentiated from uncoated objects.

Ultrawide-band communication system and method

Abstract: An impulse radio communications system using one or more subcarriers to communicate information from an impulse radio transmitter to an impulse radio receiver. The impulse radio communication system is an ultrawide-band time domain system. The use of subcarriers provides impulse radio transmissions added channelization, smoothing and fidelity. Subcarriers of different frequencies or waveforms can be used to add channelization of impulse radio signals. Thus, an impulse radio link can communicate many independent channels simultaneously by employing different subcarriers for each channel. The impulse radio uses modulated subcarrier(s) for time positioning a periodic timing signal or a coded timing signal. Alternatively, the coded timing signal can be summed or mixed with the modulated subcarrier(s) and the resultant signal is used to time modulate the periodic timing signal. Direct digital modulation of data is another form of subcarrier modulation for impulse radio signals. Direct digital modulation can be used alone to time modulate the periodic timing signal or the direct digitally modulated the periodic timing signal can be further modulated with one or more modulated subcarrier signals. Linearization of a time modulator permits the impulse radio transmitter and receiver to generate time delays having the necessary accuracy for impulse radio communications.

Full duplex ultrawide-band communication system and method

Abstract: An impulse radio transceiver for full duplex ultrawide-band communications. The transceiver comprises an impulse radio transmitter to transmit impulse radio signal pulses, an impulse radio receiver to receive impulse radio signal pulses, and means, associated with either or both of the impulse radio transmitter and the impulse radio receiver, for synchronizing the transmission and the reception of the impulse radio signal pulses for pulse interleaved communications. Pulse interleaving avoids self-interference between the transmitted impulse radio signal pulses and the received impulse radio signal pulses. In addition to pulse interleaved communications, bursts of pulses can be transmitted between two transceivers in an interleaved fashion. Alternatively, two different pulse repetition rates are to be used to transmit and receive impulse radio signal pulses simultaneously. A blanking means for blanking selected pulses of the received or transmitted impulse radio signal pulses can be used to avoid interference.

Communications systems and methods

Abstract: This invention generally relates to networks of communications devices, in particular ultra wideband (UWB) communications devices. An ultra-wideband (UWB) network comprising a plurality of UWB devices each forming a node of said network, pairs of said UWB devices being configured for communication with one another using one of a plurality of UWB channels, each said UWB device comprising a UWB transceiver for bidirectional communication over one or more of said UWB channels with at least one other of said UWB devices; and a device controller coupled to said UWB transceiver, said controller being configured to determine a said UWB channel for use in establishing a communication link with each other UWB device; whereby said network is configured for automatic construction of a set of communications links between said nodes of said network.

Ultra-wideband radar motion sensor

Abstract: A motion sensor is based on ultra-wideband (UWB) radar. UWB radar range is determined by a pulse-echo interval. For motion detection, the sensors (40) operate by staring at a fixed ranged and then sensing any change in the averaged radar reflectivity at that range. A sampling gate (figure 4) is opened at a fixed delay after the emission of a transmit pulse. The resultant sampling gate output is averaged over repeated pulses. Changes in the averaged sampling gate output represent changes in the radar reflectivity at a particular range, and thus motion.

Fast locking mechanism for channelized ultrawide-band communications

Abstract: A receiver for acquisition and lock of an impulse radio signal comprising an adjustable time base to output a sliding periodic timing signal having an adjustable repetition rate, and a decode timing modulator to output a decode signal in response to the periodic timing signal. The impulse radio signal is cross correlated with the decode signal to output a baseband signal. The receiver integrates T samples of the baseband signal and a threshold detector uses the integration results to detect channel coincidence. A receiver controller stops sliding the time base when channel coincidence is detected. A counter and extra count logic, coupled to the controller, are configured to increment or decrement the address counter by a one or more extra counts after each T pulses is reached in order to shift the PN code modulo for proper phase alignment of the periodic timing signal and the received impulse radio signal.