Nortel Networks Corporation

Roger Adrian Perrott

Martin Stevens Smith

Sonya Victoria Amos

Ian A Abraham

Dawn K Power

Eric George Hasell

Multiple input multiple output (MIMO) systems are able to provide wireless communications at increased data rates. These systems involve using a plurality of antennas on both the transmitter and receiver and the problem of how to accommodate such structures in user terminals, which are often required to be hand held then arises. An antenna arrangement which is suitable for MIMO communications and which can be incorporated into a user terminal such as a personal digital assistant (PDA) is described. A pair of co-polarised umbrella monopoles and a slot antenna are incorporated into a flap which extends at approximately 90&#xb0; to the body of the PDA. A fourth monopole is mounted and protrudes from the PDA itself.

User terminal antenna arrangement for multiple-input multiple-output communications

A dual band antenna is described which comprises a single band antenna surrounded by single band antenna elements. For example, the single band antenna may be a horn operating at a first frequency band and the single band antenna elements may be a flat plate array. In this case, the flat plate array contains an aperture through which the horn extends. The single band antenna and single band antenna elements are positioned such that a transmit and a receive antenna beam are created which have approximately equal phase centres and beamwidths. The single band antenna may also be an array of antenna elements, such as a flat plate array. Alternatively the single band antenna may be formed from dipole elements. As well as this the single band antenna elements may be dipole elements, flat-plate elements or any other suitable type of elements. The dual band antennas described may be used as feeds for reflector antennas or as antennas in their own right. The dual band antennas and feeds described are particularly useful for subscriber satellite communication systems such as satellite TV, with receive signals being in the Ku band and transmit signals being in the Ka band.

Dual band antenna

A flat-plate dual band array antenna is described which comprises two flat plate arrays of single band antenna elements, each of which operates in a different frequency band. The two flat plate arrays are positioned one above the other, with areas in the upper flat plate array being removed in order that the antenna elements in the lower flat plate array can radiate through the upper flat plate array. The geometric arrangement of the antenna elements is such that distribution networks for the antenna elements can be accommodated in the limited space available. Dual band flat-plate array feeds for a reflector antenna are also described. These use at least two flat-plate arrays that are positioned one above the other. Again regions in the upper flat-plate array are removed to allow the lower flat-plate to operate through the upper one. The geometric arrangement of the antenna elements in these array feeds is such that transmit and receive beams are provided that have co-incident phase centers and approximately equal beamwidths. The flat plate array antenna and reflector antennas described are particularly useful for subscriber satellite communication systems such as satellite TV, with receive signals being in the Ku band and transmit signals being in the Ka band.

The present invention relates to a microwave flat plate or planar antenna, and a method of manufacturing the same. As the frequency of operation increases, traditional methods of manufacturing these antennas are becoming increasingly impractical. The present invention provides an antenna tri-plate structure comprising, a first dielectric layer carrying a plurality of radiating elements, a second and third dielectric layer each comprising a metallised surface having a plurality of apertures corresponding to said radiating elements, a number of dielectrics spacers formed with said second and third dielectric layers, each said spacer being located between a said aperture and a said radiating element to maintain said layers apart.

Flat plate antenna

A flat-plate dual band antenna element is described which comprises two superposed sets of excitation probes and apertures each of which operates in a different frequency band. These antenna elements are used in an array together with a plurality of single band elements to create a flat-plate, dual band array antenna that is low cost and permits monopulse alignment methods and distributed power amplification to be used. The geometric arrangement of the antenna elements is such that distribution networks for the excitation probes can be accommodated in the limited space available. Dual band flat-plate array feeds for a reflector antenna are also described. These use either a combination of the above mentioned dual band antenna elements and single band antenna elements or alternatively, two sizes of single band antenna elements. The geometric arrangement of the antenna elements in these array feeds is such that transmit and receive beams are provided that have co-incident phase centers and approximately equal beamwidths.

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Chelmsford, United Kingdom

Roger Adrian Perrott