Her Majesty the Queen in Right of Canada, As Represented by the Minister

Her Majesty the Queen in Right of Canada As Represented by the Minister of Industry Through the Communications Research Centre Canada

Her Majesty in Right of Canada As Represented by the Minister of Industry

Michel Cuhaci

Apisak Ittipiboon

Aldo Petosa

Jafar Shaker

Rajesh Kumar Mongia

Yahia Mohamed Antar

Dave Roscoe

Mohammad Reza Chaharmir

Richard LaRose

Abdel Razik Sebak

Kathia L&eacute;vis

Masahiro W Katsube

A volume hologram for modifying a characteristic of an input microwave beam and a method for manufacturing thereof are disclosed. The hologram is fabricated from a multi-layer artificial dielectric wherein each layer is made of a dielectric material and includes a lattice of inclusions, for example metal disks disposed on one side thereof, and wherein a pre-determined three-dimensional grating pattern of dielectric perturbations is induced by spatial modulating the lattice of the inclusions. The hologram can be designed for efficiently steering, reshaping, combining or splitting microwave beams.

Volume hologram

The present invention relates to a reflectarray antenna. The reflectarray antenna comprises a dielectric substrate layer disposed on a ground plane. An array of radiating elements such as microstrip patches of similar size are arranged into a regular lattice configuration on the top surface of the substrate layer. A periodic configuration of slots of variable size are provided at the bottom surface of the substrate layer. A required phase shift at each position on the reflectarray surface is obtained by adjusting the slot length on the ground plane. The incident wave from the feed excites the dominant mode on the microstrip patches The presence of slots acts as an inductive loading of the patches, which introduces a phase shift in the patch response. The inductance of each slot depends on its length. In accordance with an aspect of the invention the phase shift of the individual microstrips is modified by shining an appropriate optical image onto each individual slot element, thereby altering the radiation characteristics of the reflectarray. This approach is highly advantageous for dynamic beam scanning and beam shaping.

Antenna with variable phase shift

The invention relates to an antenna structure for radiating electromagnetic waves in predetermined polarization configurations. A dielectric substrate is provided with a copper conductive pattern printed on each side. The conductors act as scattering elements and are printed for scattering radiation provided along a first predetermined feed direction or alone a second feed direction independently. Preferably, the pattern of the copper is based on an interference pattern and two feeds are used, one to provide radiation along each of the two feed directions. When used as a traveling wave antenna, the resulting structure is flat, having a low profile, and lightweight with simple electronics. Improved isolation Occurs when the printed interference patterns each contain only a component along a single direction such that each scattering element is linear and is parallel to or orthogonal to other scattering elements.

Dual-polarized and circular-polarized antennas

A dielectric loaded microstrip patch antenna is provided for delivering relatively wide operational bandwidth dual-band, with relatively good isolation and flexibility for circular polarization, while having a compact design and lightweight to suit mobile and wireless applications. The microstrip patch antenna has a conducting ground plane and a patch radiator. The patch radiator is spaced from the ground plane by a substantial distance having a first dielectric material therein. A slot feed in the ground plane provides the patch radiator with radio signal energy across the space having the first dielectric material therein. A piece of a second dielectric material is disposed adjacent the slot feed between the patch radiator and the ground plane. The second dielectric material has a dielectric constant that is higher than the dielectric constant of the first dielectric material. The piece of the second dielectric material acts to load the feed in order to improve coupling between the slot and the patch. The piece has a dimension along one of the x and y axes smaller than a dimension of the patch along a same axis. Since the piece is situated between the ground plane and the patch it determines operational characteristics of the microstrip patch antenna.

Dielectric loaded microstrip patch antenna

Due to the frequency dependence of phasing mechanisms applied in planar printed reflectors, when using planar printed reflector antennas beam squint occurs as the frequency is scanned within the operating band. In order to reduce or eliminate beam squint, an incident signal incident upon a reflector is altered in such a way that the outgoing signal retains a same direction. In an embodiment, this is achieved by providing feed elements in different locations, each feed element for feeding a signal of a different frequency. In another embodiment, two reflector arrays are used wherein beam squint caused by the first reflector array is compensated for by the second reflector array.

Techniques for the cancellation of beam squint in planar printed

A dielectric resonator antenna system is disclosed wherein a dielectric material having a high dielectric constant is placed between a dielectric resonator antenna (DRA) and the antenna feed. Preferably the dielectric material having a high dielectric constant is either in the form of an insert within a cavity of the DRA or alternatively is in the form of a thin layer between the feed and the DRA for enhancing coupling therebetween. It is preferred that the high dielectric constant material be at least twice the value of the dielectric resonator antenna.

Broadband nonhomogeneous multi-segmented dielectric resonator antenna

In order to reduce size and facilitate incorporation into planar multi-layer microwave integrated circuits, a microwave hybrid, specifically a Magic-Tee, is formed using microstrip circuit elements and aperture coupling. The Magic-Tee comprises a ground plane interposed between dielectric printed circuit boards. The outermost surface of one of the boards carries a Tee circuit comprising microstrip branch arm conductors with a microstrip conductor projecting transversely from its middle, the Tee junction, to form the leg of the Tee. The outermost surface of the other board comprises a line in the form of a microstrip conductor. An aperture is provided in the ground plane at a position between the Tee junction and an underlying part of the line conductor. Various Tee junction configurations, such as Y or .DELTA., may be implemented also. The magic Tee may be an integral part of an MIC or MMIC device.

Growing community of inventors

Ottawa, Canada

Michel Cuhaci