Antenna beam forming system

• US 5,233,358 A
• Filed: 04/24/1989
• Issued: 08/03/1993
• Est. Priority Date: 04/24/1989
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Murphy, Timothy A.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US07/342,266
• Time in Patent Office: 1,562 Days
• Field of Search: 342/373, 342/371, 342/372, 342/375, 342/368, 342/383, 342/157, 55/1
• US Class Current: 342/375
• CPC Class Codes: H01Q 3/22 varying the orientation in accordance with variation of frequency of radiated wave
• CPC Class Codes: H04B 7/2041 Spot beam multiple access

Abstract

An improved antenna beam forming system 10 for generating a set of directed beams wherein each beam may include carrier signals of more than one frequency is disclosed herein. The improved beam forming system of the present invention includes a first beam forming network 20 for providing a first set of signals. The first beam forming network 20 includes a plurality of phase shifting elements 22 for providing a first phase relationship among the first set of signals in response to first carrier signal of a first frequency. The system 10 of the present invention further includes a second beam forming network 30 for providing a second set of signals. The second beam forming network includes a plurality of phase shifting elements 32 for again providing the first phase relationship among the second set of signals in response to a second carrier signal of a second frequency. An array of summing elements 40 for summing respective signals of the first and second sets of signals is included to provide a third set of signals. The third set of signals is transmitted by a phased array antenna 60 thereby providing first and second contemporaneous beams which overlap at a common surface.

Claims

1. An improved antenna beam forming system for providing first and second contemporaneous electromagnetic beams overlapping at a common surface comprising:

first beam forming network means for providing a first set of signals, said first beam forming network means including first phase shifting means with a first phase shifter having a first phase response as a function of frequency for providing a first phase relationship among said first set of signals in response to a first carrier signal of a first frequency;

second beam forming network means for providing a second set of signals, said second beam forming network means including second phase shifting means with a second phase shifter having a second phase response as a function of frequency for providing said first phase relationship among said second set of signals in response to a second carrier signal of a second frequency, said first and second phase responses of said first and second respective phase shifters being substantially identical and offset in frequency by the difference of said first and second frequencies;

summing means connected to the outputs of the first phase shifter and the second phase shifter for summing the outputs thereof to provide a third set of signals; and

phased array means for transmitting said third set of signals to provide said first and second contemporaneous beams.

2. The invention of claim 1 including spatial transformation means for at least partially conducting a spatial transformation of the amplitude and phase distribution of said third set of signals to provide a fourth set of signals.

3. The improved antenna beam forming system of claim 2 wherein said spatial transformation is either a Fourier transform or an inverse Fourier transform.

4. The improved antenna beam forming system of claim 2 wherein said spatial transformation means includes a Butler matrix.

5. A method for providing first and second contemporaneous electromagnetic beams overlapping at a common surface including the steps of:

a) providing a first set of signals having a first phase response as a function of frequency and a first phase relationship in response to a first carrier signal of a first frequency;

b) providing a second set of signals having a second phase response as a function of frequency and said first phase relationship among said second set of signals in response to a second carrier signal of a second frequency, said first and second phase responses being substantially identical and offset in frequency by the difference of said first and second frequencies;

c) summing respective signals from the first and second sets of signals to provide a third set of signals; and

d) transmitting said third set of signals to provide said first and second contemporaneous beams.