Abstract: A photoconductive antenna has an array of antenna electrodes on or in a photoconductive substrate. The photoconductive substrate is irradiated with light from a pulsed laser via micro-lenses above respective gaps between antenna electrodes. This makes the photoconductive substrate temporarily conductive, causing pulsed electric antenna currents that can be used for transmission of electromagnetic radiation in the Terahertz range. The bias circuit of the antenna is configured to determine voltages applied to the antenna electrodes by capacitive voltage division over a series of successive capacitors, each capacitor being formed by the antenna electrodes of a respective pair of successive ones of the antenna electrodes in the array as plates of the capacitor adjacent to a respective one of the gaps.

Abstract: A photoconductive antenna has an array of antenna electrodes on or in a photoconductive substrate. The photoconductive substrate is irradiated with light from a pulsed laser via micro-lenses above respective gaps between antenna electrodes. This makes the photoconductive substrate temporarily conductive, causing pulsed electric antenna currents that can be used for transmission of electromagnetic radiation in the Terahertz range. The bias circuit of the antenna is configured to determine voltages applied to the antenna electrodes by capacitive voltage division over a series of successive capacitors, each capacitor being formed by the antenna electrodes of a respective pair of successive ones of the antenna electrodes in the array as plates of the capacitor adjacent to a respective one of the gaps.

Abstract: An antenna element suitable for integrated arrays at terahertz frequencies is disclosed. The antenna element comprises an extended spherical (e.g. hemispherical) semiconductor lens, e.g. silicon, antenna fed by a leaky wave waveguide feed. The extended spherical lens comprises a substantially spherical lens adjacent a substantially planar lens extension. A couple of TE/TM leaky wave modes are excited in a resonant cavity formed between a ground plane and the substantially planar lens extension by a waveguide block coupled to the ground plane. Due to these modes, the primary feed radiates inside the lens with a directive pattern that illuminates a small sector of the lens. The antenna structure is compatible with known semiconductor fabrication technology and enables production of large format imaging arrays.

Abstract: A three-dimensional imaging radar operating at high frequency e.g., 670 GHz radar using low phase-noise synthesizers and a fast chirper to generate a frequency-modulated continuous-wave (FMCW) waveform, is disclosed that operates with a multiplexed beam to obtain range information simultaneously on multiple pixels of a target. A source transmit beam may be divided by a hybrid coupler into multiple transmit beams multiplexed together and directed to be reflected off a target and return as a single receive beam which is demultiplexed and processed to reveal range information of separate pixels of the target associated with each transmit beam simultaneously. The multiple transmit beams may be developed with appropriate optics to be temporally and spatially differentiated before being directed to the target. Temporal differentiation corresponds to a different intermediate frequencies separating the range information of the multiple pixels.

Abstract: An antenna element suitable for integrated arrays at terahertz frequencies is disclosed. The antenna element comprises an extended spherical (e.g. hemispherical) semiconductor lens, e.g. silicon, antenna fed by a leaky wave waveguide feed. The extended spherical lens comprises a substantially spherical lens adjacent a substantially planar lens extension. A couple of TE/TM leaky wave modes are excited in a resonant cavity formed between a ground plane and the substantially planar lens extension by a waveguide block coupled to the ground plane. Due to these modes, the primary feed radiates inside the lens with a directive pattern that illuminates a small sector of the lens. The antenna structure is compatible with known semiconductor fabrication technology and enables production of large format imaging arrays.

Abstract: A three-dimensional imaging radar operating at high frequency e.g., 670 GHz radar using low phase-noise synthesizers and a fast chirper to generate a frequency-modulated continuous-wave (FMCW) waveform, is disclosed that operates with a multiplexed beam to obtain range information simultaneously on multiple pixels of a target. A source transmit beam may be divided by a hybrid coupler into multiple transmit beams multiplexed together and directed to be reflected off a target and return as a single receive beam which is demultiplexed and processed to reveal range information of separate pixels of the target associated with each transmit beam simultaneously. The multiple transmit beams may be developed with appropriate optics to be temporally and spatially differentiated before being directed to the target. Temporal differentiation corresponds to a different intermediate frequencies separating the range information of the multiple pixels.

Abstract: A method for providing an information unit to a user is described, wherein the information unit describes an object having a predetermined spatial relationship to the user. The method includes detecting a kind of movement or a position of the user. Depending on the detected kind of movement or the position of the user, a geographic selection criterion is adjusted, wherein, depending on the predetermined spatial relationship of object to user, the geographic selection criterion specifies whether the information unit is provided or not. If a location of the user is located such with respect to a geographic position of the user that the geographic selection criterion is met, the information unit for the object is reproduced. An advantage is that the concept may be employed in applications in which the user gets into different environments and situations which, in turn, require different geographic selection criteria.

Abstract: A method for providing an information unit to a user is described, wherein the information unit describes an object having a predetermined spatial relationship to the user. The method includes detecting a kind of movement or a position of the user. Depending on the detected kind of movement or the position of the user, a geographic selection criterion is adjusted, wherein, depending on the predetermined spatial relationship of object to user, the geographic selection criterion specifies whether the information unit is provided or not. If a location of the user is located such with respect to a geographic position of the user that the geographic selection criterion is met, the information unit for the object is reproduced. An advantage is that the concept may be employed in applications in which the user gets into different environments and situations which, in turn, require different geographic selection criteria.