.pi.-Loop phase bit apparatus

• US 4,001,734 A
• Filed: 10/23/1975
• Issued: 01/04/1977
• Est. Priority Date: 10/23/1975
• Status: Expired due to Term

• Current Assignee: Hughes Aircraft Company (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Burns, Richard W.
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Nussbaum, Marvin
• Application Number:
  US05/625,271
• Time in Patent Office: 439 Days
• Field of Search: 333/29, 333/31 R, 333/31 A, 333/7 R, 333/7 D, 333/84 R, 333/84 M, 333/97 R, 333/97 S, 307/256, 307/320
• US Class Current: 333/164
• CPC Class Codes: H01P 1/185 using a diode or a gas filled discharge tube

Abstract

The use of electronically variable phase shifters is required in phased array radar systems. Diode phase shifters are particularly well suited for use in phased array radar systems because they have size and weight advantage over other types of phase shifting components such as ferrite devices and traveling wave tubes and, in addition, offer the potential of cost reductions through the application of batch processing techniques. In accordance with the present invention, a phase bit is provided by the appropriate forward or reverse biasing of one series and one shunt diode to switch between a π circuit and a loop transmission line circuit shunting the equivalent capacitance of the series diode when reverse biased.

Claims

1. An apparatus for selectively introducing a predetermined phase shift in a signal, said apparatus comprising a signal input terminal and a signal output terminal, a first unidirectionally conducting device connected from said signal input terminal to said signal output terminal;

a first segment of transmission line connected from said signal input terminal to a first junction, said first segment of transmission line being greater than one-quarter wavelength and less than one-half wavelength long at the frequency of said signal;

a second segment of transmission line connected from said output terminal to said first junction, the length of said second segment of transmission line being substantially equal to that of said first segment;

a second unidirectionally conducting device connected from said first junction to a second junction maintained at a substantially fixed direct-current reference potential; and

means connected to said first and second segments of transmision line for simultaneously reverse biasing said first and second unidirectionally conducting devices to provide a reference phase shift in said signal or for simultaneously forward biasing said first and second unidirectionally conducting devices thereby to selectively increase said reference phase shift by said predetermined phase shift.

2. An apparatus for selectively introducing a predetermined phase shift in a signal, said apparatus comprising a signal input terminal and a signal output terminal;

a first unidirectionally conducting device connected from said signal input terminal to said signal output terminal, said first unidirectionally conducting device being poled in a predetermined direction in proceeding from said signal input terminal to said signal output terminal;

a first segment of transmission line connected from said signal input terminal to a first junction, said first segment of transmission line being greater than one-quarter wavelength and less than one-half wavelength long at the frequency of said signal;

a second segment of transmission line connected from said signal output terminal to said first junction, the length of said second segment of transmission line being substantially equal to that of said first segment;

a second unidirectionally conducting device connected from said first junction to a second junction maintained at a substantially fixed direct-current reference potential and poled in said predetermined direction in proceeding from said first junction to said second junction;

means coupled to said signal output terminal for maintaining the quiescent potential thereof at said substantially fixed direct-current reference potential; and

means coupled to said signal input terminal for simultaneously reverse biasing said first and second unidirectionally conducting device to provide a reference phase shift in said signal or for simultaneously forward biasing said first and second unidirectionally conducting devices thereby to selectively increase said reference phase shift by said predetermined phase shift.

3. The apparatus for selectively introducing a predetermined phase shift in a signal as defined in claim 2 wherein said means coupled to said signal output terminal for maintaining the quiescent potential thereof at said substantially fixed direct-current reference potential includes a radio-frequency choke connected from said signal output terminal to said second junction and a blocking capacitor interconnected in said second segment of transmission line between said first junction and said signal output terminal.

4. The apparatus for selectively introducing a predetermined phase shift in a signal as defined in claim 2 wherein said first and second segments of transmission line are each substantially equal to three-eighths wavelength long at the frequency of said signal.

5. An apparatus for selectively introducing a predetermined phase shift in a signal, said apparatus comprising a signal input terminal and a signal output terminal;

a first diode connected from said signal input terminal to said signal output terminal, said first diode being poled in a direction to allow current flow towards said signal input terminal;

a first segment of transmission line connected from said signal input terminal to a first junction, said first segment of transmission line being three-eighths wavelength at the frequency of said signal;

a second segment of transmision line connected from said signal output terminal to said first junction, the length of said second segment of transmission line being substantially equal to that of said first segment;

a second diode connected from said first junction to ground and poled to allow bias current flow towards said first junction; and

means coupled to said first and second segments of transmission line for simultaneously reverse biasing said first and second diodes thereby to generate a reference phase shift in said signal or for simultaneously forward biasing said first and second diodes thereby to selectively increase said reference phase shift by said predetermined phase shift.

6. An apparatus for selectively introducing a predetermined phase shift in a signal, said apparatus comprising a signal input terminal and a signal output terminal, a first unidirectionally conducting device connected from said signal input terminal to said signal output terminal;

a first segment of transmission line connected from said signal input terminal to a first junction, said first segment of transmission line being greater than one-quarter wavelength and less than one-half wavelength long at the frequency of said signal;

a second segment of transmission line connected from said signal output terminal to said first junction, the length of said second segment of transmission line being substantially equal to that of said first segment;

a second unidirectionally conducting device connected from said first junction to a second junction maintained at a substantially fixed direct-current reference potential; and

means coupled to first and second unidirectionally conducting devices for simultaneously rendering said first and second unidirectionally conducting devices non-conductive to generate a reference phase shift in said signal or for simultaneously rendering said first and second unidirectionally conductive devices conductive thereby to selectively increase said reference phase shift by said predetermined phase shift.

7. The apparatus for selectively introducing a predetermined phase shift in a signal as defined in claim 6 wherein said predetermined phase shift is in the range of from 22.5°

to 180°

.