Multichannel homodyne receiver

• US 4,360,810 A
• Filed: 01/19/1981
• Issued: 11/23/1982
• Est. Priority Date: 01/19/1981
• Status: Expired due to Term

• Current Assignee: Amtech Corporation 536 Paul Place White Rock New Mexico, United States Department of Energy
• Original Assignee: United States Department of Energy
• Inventors: Landt, Jeremy A.
• Primary Examiner(s): Tubbesing, T. H.
• Application Number:
  US06/226,283
• Time in Patent Office: 673 Days
• Field of Search: 343/5 PD, 343/6.5 SS, 343/6.5
• US Class Current: 342/44
• CPC Class Codes: G01S 13/32 using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
• CPC Class Codes: G01S 13/82 wherein continuous-type signals are transmitted
• CPC Class Codes: G01S 7/036 involving a transfer mixer

Abstract

A homodyne radar transmitter/receiver device which produces a single combined output which contains modulated backscatter information for all phase conditions of both modulated and unmodulated backscatter signals. The device utilizes taps along coaxial transmission lines, strip transmission line, and waveguides which are spaced by 1/8 wavelength or 1/6 wavelength, etc. This greatly reduces costs by eliminating separate transmission and reception antennas and an expensive arrangement of power splitters and mixers utilized in the prior art.

Claims

1. A homodyne radar transmitter/receiver device comprising:

microwave source means for producing a microwave transmission signal;

a combination transmitter/receiver antenna for transmitting said microwave transmission signal and detecting both modulated and unmodulated backscatter signals;

transmission line means connecting said microwave source and said combination transmitter/receiver antenna;

at least two output connectors attached to said transmission line means at intervals equal to approximately 1/8 wavelength of said microwave transmission signal;

means for detecting attached to said output connectors;

low pass filter means connected to said means for detecting;

signal combiner/amplifier means connected to said low pass filter means for producing a single output containing modulated backscatter information for all phase conditions of said modulated and unmodulated backscatter signals.

2. The system of claim 1 wherein said transmission line means comprises a waveguide.

4. The system of claim 1 wherein said transmission line means comprises a coaxial cable.

3. The system of claim wherein said transmission line means comprises a stripline.

5. A homodyne radar transmitter/receiver device comprising:

microwave source means for producing a microwave transmission signal;

a combination transmitter/receiver antenna for transmitting said microwave transmission signal and detecting both modulated and unmodulated backscatter signals;

transmission line means connecting said microwave source and said combination transmitter/receiver antenna;

at least three output connectors attached to said transmission line means at intervals equal to approximately 1/6 wavelength of said microwave transmission signal;

means for detecting attached to said output connectors;

low pass filter means connected to said means for detecting;

signal combiner/amplifier means connected to said low pass filter means for producing a single output containing modulated backscatter information for all phae conditions of said modulated and unmodulated backscatter signals.

6. In a transponder system, a single antenna homodyne radar system for producing a combined output signal representative of a modulated backscatter signal produced by a transponder regardless of ambiguity points produced by the interference of modulated and unmodulated backscatter signals comprising:

rf source means for generating a microwave transmission signal;

antenna means for transmitting said microwave transmission signal and receiving said modulated and unmodulated backscatter signals;

transmission line means for connecting said rf source means and said antenna means such that a first standing wave pattern is produced in said transmission line means by the combination of said microwave transmission signal and said modulated backscatter signal and a second standing wave pattern is produced in said transmission line means by the combination of said microwave transmission signal and said unmodulated backscatter signal;

a plurality of output channels connected to said transmission line means, said plurality of output channels spaced by a distance equal to approximately 1/8 wavelength of said microwave transmission signal such that at least one channel of each adjacent pair of said plurality of output channels contains said received modulated backscatter signal regardless of ambiguity points caused by the coincidence of said first and second standing wave patterns;

means for combining said plurality of output channels to produce a single combined output channel representative of said modulated backscatter signal.

7. The system of claim 6 wherein said transmission line means comprises a stripline.

8. The system of claim 6 wherein said transmission line means comprises a waveguide.

9. The system of claim 6 wherein said transmission line means comprises a coaxial cable.

10. The system of claim 6 wherein said plurality of output channels comprises two output channels.