MICROSTRIP PHASE SHIFTER HAVING SWITCHABLE PATH LENGTHS

• US 3,568,105 A
• Filed: 03/03/1969
• Issued: 03/02/1971
• Est. Priority Date: 03/03/1969
• Status: Expired due to Term

• Current Assignee: ITT Corporation (ITT, Inc.)
• Original Assignee: Robert A. Felsenheld
• Inventors: Felsenheld, Robert A.
• Application Number:
  US04/803,793
• Time in Patent Office: 729 Days
• US Class Current: 333/161
• CPC Class Codes: H01P 1/185 using a diode or a gas filled discharge tube

Abstract

A microstrip phase shifter is inserted in a waveguide aperture, the phase shifting network consists of lightweight transmission line sections which can be switched by microwave diodes to provide the required phase shift. The diodes are switched in pairs, forward or back biased, so that the wave will traverse through a given path to complete the phase shifting according to the switched pair of the diodes.

Claims

1. A phase shifter comprising:

first and second fixed length paths forming a first junction;

a shunting path across said first junction;

a quarter-wave stub coupled to each of said first and second fixed length paths;

a first switchable device located at said first junction;

a second switchable device coupled between said shunting path and a shorting plane; and

means coupled for switching said first and second devices from one state to another, said means including a source of bias voltage coupled to one of said stubs, a first capacitor coupled to the bias voltage stub, and a second capacitor located in said shunting path, whereby RF energy is caused to follow a fixed length path or an extra length path formed by said shunting path.

2. A phase shifter according to claim 1 wherein said first and second switchable devices are diodes.

3. A phase shifter according to claim 2, wherein said bias voltage applied to said bias stub causes said first and second diodes to be simultaneously forward or backbiased.

4. A phase shifter according to claim 3, wherein said bias stub is coupled to said shorting plane by said first capacitor, and said stub connected to said second fixed path is coupled directly to said shorting plane, whereby when said diodes are forward biased said phase shifter emulates quarter-wave lines.

5. A phase shifting array, each section of the array comprising:

a first junction formed by first and second fixed length paths;

a shunting path across said first junction to provide the phase shift in electrical degrees for each section;

a pair of quarter-wave stubs, each cOupled to one of said first and second fixed length paths;

a first solid state device located at said first junction;

a second solid state device coupled between said shunting path and a common shorting plane; and

means for switching said first and second devices from one biased state to another, said means includes a source of bias voltage coupled to one of said stubs, a first capacitor coupled to the bias voltage stub, and a second capacitor positioned within said shunting path, whereby RF energy is caused to follow in response to said switching a fixed length path or an extra length path formed by said shunting path.

6. A phase shifting array according to claim 5 wherein said first and second solid-state devices are diodes.

7. A phase shifting array according to claim 6 wherein said bias voltage applied to said bias stub causes said first and second diodes to be simultaneously forward or backbiased.

8. A phase shifting array according to claim 7 wherein said bias stub is coupled to said common shorting plane by said first capacitor, and said stub connected to said second fixed path is directly coupled to said common shorting plane, whereby when said diodes are forward biased this phase shifting section emulates quarter-wave lines.