Antenna feed system

• US 6,046,655 A
• Filed: 11/10/1998
• Issued: 04/04/2000
• Est. Priority Date: 11/10/1997
• Status: Expired due to Fees

• Current Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Datron/Transco, Inc.
• Inventors: Cipolla, Frank W.
• Primary Examiner(s): GENSLER, PAUL L
• Application Number:
  US09/189,770
• Time in Patent Office: 511 Days
• Field of Search: 333/21 A, 333/125, 333/126, 333/135, 333/137, 343/756, 343/786
• US Class Current: 333/137
• CPC Class Codes: H01Q 1/247 with frequency mixer, e.g. for direct satellite reception or Doppler radar
• CPC Class Codes: H01Q 13/0258 Orthomode horns orthomode transducers H01P1/161

Abstract

An antenna feed system provides reception of both circularly polarized signals and linearly polarized signals. An antenna is employed which is dual-circularly polarized and circularly polarized signals received thereby are separated into right and left hand components which are placed in phase quadrature relationship by means of a 90 degree hybrid coupler. Signals received by the antenna which have dual-orthogonal linear polarization are also separated into left and right hand components in quadrature relationship by means of a 90 degree hybrid coupler. A programmable phase shifter is utilized to set the orientation of the linearly polarized reception vector. A fixed delay line and an attenuator are provided for use in balancing the amplitude and phase of the right and left hand components of the linearly polarized signals.

Claims

1. A system for enabling the detection of linearly polarized signals received by a circularly polarized antenna comprising:

a first ninety degree hybrid coupler;

feed means for separately feeding right and left hand polarized components of the signals received by said antenna to said hybrid coupler;

said hybrid coupler dividing the signals into two equal parts and placing said parts in quadrature relationship with each other, said quadrature related parts comprising two separate output signals of said coupler;

a phase shifter;

an attenuator;

a delay line connected to said attenuator; and

a second ninety degree hybrid coupler;

the phase shifter receiving one output signal and being programmed to set the linear orientation of the linearly polarized reception vector;

the attenuator and delay line receiving the other output signal and being set to balance the amplitude and phase between the signal fed to the attenuator and the signal fed to the phase shifter;

the outputs of said phase shifter and said delay line being fed to said second hybrid coupler, said second hybrid coupler dividing said signals into equal parts which are in quadrature relationship, said quadrature related signals comprising vertically and horizontally linearly polarized outputs corresponding to linearly polarized incoming signals.

2. A system for enabling the detection of both circularly and linearly polarized signals received by a circularly polarized antenna comprising:

a first ninety degree hybrid coupler;

feed means for separately feeding right and left hand polarized components of the signals received by the antenna to said first hybrid coupler;

said first hybrid coupler dividing the signals into two equal parts and placing said parts in quadrature relationship with each other, said quadrature related parts providing two separate output signals of said coupler;

a phase shifter;

an attenuator;

a delay line connected to said attenuator;

first and second two way transfer switches, said switches each receiving one of the output signals of said hybrid coupler and being operable to either feed the signals fed thereto as right and left hand circularly polarized outputs or to feed one of said signals to said attenuator and the other of said signals to said phase shifter;

and a second ninety degree hybrid coupler;

the phase shifter being programmed to set the linear orientation of the linearly polarized reception vector;

the attenuator and delay line being set to balance the amplitude and phase between the signal fed to the attenuator and the signal fed to said phase shifter;

the outputs of said phase shifter and said delay line being fed to said second hybrid coupler, said second hybrid coupler dividing said signals into equal parts which are in quadrature relationship, said quadrature related signals being vertically and horizontally linearly polarized outputs in accordance with linearly polarized incoming signals.

3. A method for enabling the detection of linearly polarized signals received by a circularly polarized antenna having left and right hand polarized components comprising the steps of:

dividing the left and right hand signal components into two equal signals and placing said signals in quadrature relationship with each other;

phase shifting one of said two signals to set the linear orientation of the linearly polarized reception vector;

attenuating and delaying the other of said two signals to balance the amplitude and phase relationship between the two signals; and

dividing said signals into equal parts which are in quadrature relationship with each other, said quadrature related signals being vertically and horizontally linearly polarized corresponding to the linearly polarized received by the antenna.

4. The method of claim 3 wherein the delaying and attenuation of the other of said two signals is done remotely.