Mobile communication satellite payload

• US 5,623,269 A
• Filed: 02/02/1995
• Issued: 04/22/1997
• Est. Priority Date: 05/07/1993
• Status: Expired due to Fees

• Current Assignee: Space Systems/Loral Incorporated (Loral Space and Communications Incorporated)
• Original Assignee: Space Systems/Loral Incorporated (Loral Space and Communications Incorporated)
• Inventors: Tsao, Chich-Hsing A., Hirshfield, Edward
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US08/382,884
• Time in Patent Office: 810 Days
• Field of Search: 342/371, 342/354, 343/700 MS
• US Class Current: 342/354
• CPC Class Codes: B64G 1/1007 Communications satellites
• CPC Class Codes: B64G 1/1085 Swarms and constellations
• CPC Class Codes: B64G 1/66 Arrangements or adaptations of apparatus or instruments, not otherwise provided for
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 21/064 using horn or slot aerials slotted waveguides arrays H01Q21/005
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00
• CPC Class Codes: H04B 7/18571 for satellites; for fixed or mobile stations
• CPC Class Codes: H04B 7/2041 Spot beam multiple access
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A communications satellite payload provides for efficient communications between user devices, such as hand held cellular telephones, and terrestrial gateways that may be connected to world-wide public telephone and telegraph (PTTs) networks. The satellite payload simultaneously supports a plurality of independent antenna beams, for example 12 or 16 beams, on both the uplink and downlink for user devices employing full duplex communications. The satellite payload furthermore supports an identical number of full duplex channels between a terrestrial gateway and the satellite. The communications satellite payload is carried by one satellite of a plurality of such satellites in a low earth orbit (LEO) constellation to provide worldwide communications. Downlink beam forming occurs prior to final amplification of transmitted signals, thereby reducing losses within the beam forming equipment. A multi-element phased array of receiving antennas and a multi-element phased array of transmitting antennas is also disclosed, wherein each element of each phased array is utilized for each individual one of a plurality of received or transmitted beams.

Claims

1. A satellite payload for use with a communication system, the payload comprising:

a phased array receiving antenna assembly having n receiver elements for receiving RF signals within a first band of frequencies;

first beam forming means comprising power divider means and having an input coupled to each of said n receiver elements for forming m uplink beams from RF signals received by said phased array receiving antenna assembly, wherein n is greater than one, and wherein m is less than n;

ground station communication means, having an input coupled an output of said first beam forming means, for converting said m uplink beams into RF signals within a second band of frequencies and for transmitting RF signals to and for receiving RF signals from a ground station, the transmitted and received RF signals being within said second band of frequencies;

second beam forming means comprising power combining means and having an input coupled to an output of said ground station communication means for forming m downlink beams from the RF signals received from said ground station, said m downlink beams being formed within a third band of frequencies; and

a phased array transmitting antenna assembly having n transmitter elements for transmitting said m downlink beams as RF signals within said third band of frequencies, each of said n transmitter elements having a power amplifier means associated therewith, each of said power amplifier means having an input coupled to an output of said second beam forming means and an output coupled to one of said transmitter elements, wherein each of said n transmitter elements transmits RF energy for each of said m downlink beams.

2. A satellite payload as set forth in claim 1, wherein said phased array transmitter antenna assembly comprises:

said n transmitter elements that are arranged in a predetermined pattern, each of said n transmitter elements comprising an electrically conductive patch that is disposed upon a surface of a multi-layered circuit board, and further comprising n two cavity filters individual ones of which are electrically coupled to one of said n patches, said n two cavity filters being formed within a plurality of layers of said multi-layered circuit board, the plurality of layers underlying said surface.

3. A satellite payload as set forth in claim 1, wherein said phased array receiver antenna assembly comprises:

said n receiver elements that are arranged in a predetermined pattern, each of said n receiver elements comprising an electrically conductive patch that is disposed upon a surface of a multi-layered circuit board, and further comprising n two cavity filters individual ones of which are electrically coupled to one of said patches, said n two cavity filters being formed within a plurality of layers of said multi-layered circuit board, the plurality of layers underlying said surface.

4. A satellite communication system, comprising:

a plurality of terrestrial-based user terminals for transceiving at least voice communications using a Code Division Multiple Access (CDMA) technique;

at least one terrestrial-based ground station for transceiving at least voice communications using the CDMA technique; and

at least one satellite repeater for relaying at least voice communications between said plurality of user terminals and said at least one ground station, said at least one satellite repeater having a communications payload comprised of;

a phased array receiving antenna having n receive elements arranged in a predetermined pattern for receiving RF signals from user terminals, said n receive elements each having receive amplifier means associated therewith, each of said n receive elements comprising an electrically conductive patch that is disposed upon a surface of a first multi-layered substrate, and further comprising n multi-cavity receive filters individual ones of which are electrically coupled to one of said patches, said n multi-cavity filters being formed within a plurality of layers of said first multi-layered substrate, the plurality of layers underlying said surface of said first multi-layered substrate;

first beam forming means having an input coupled to each of said n receive elements for forming m uplink beams from RF signals received by said phased array receiving antenna, wherein n is greater than one, and wherein m is less than n;

ground station communication means, having an input coupled an output of said first beam forming means, for frequency converting said m uplink beams and for transmitting RF signals to and for receiving RF signals from said at least one ground station;

second beam forming means having an input coupled to an output of said ground station communication means for forming m downlink beams from the RF signals received from said ground station; and

a phased array transmitting antenna having n transmit elements arranged in a predetermined pattern for transmitting said m downlink beams to user terminals, each of said transmit elements having a power amplifier means associated therewith, each of said power amplifier means having an input coupled to an output of said second beam-forming means and an output coupled into free space via one of said transmit elements, wherein each of said n transmit elements transmits RF energy for each of said m downlink beams, each of said n transmit elements comprising an electrically conductive patch that is disposed upon a surface of a second multi-layered substrate, and further comprising n multi-cavity filters individual ones of which are electrically coupled to one of said transmit element patches, said n multi-cavity filters being formed within a plurality of layers of said second multi-layered substrate, the plurality of layers underlying said surface of said second multi-layered substrate.