Divider/combiner amplifier

• US 4,424,496 A
• Filed: 10/13/1981
• Issued: 01/03/1984
• Est. Priority Date: 10/13/1981
• Status: Expired due to Fees

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Nichols, Lawrence J., MacMaster, George H.
• Primary Examiner(s): Mullins, James B.
• Assistant Examiner(s): Wan, Gene
• Application Number:
  US06/310,011
• Time in Patent Office: 812 Days
• Field of Search: 330/54, 330/56, 330/286, 330/287
• US Class Current: 330/286
• CPC Class Codes: H03F 3/58 using travelling-wave tubes

Abstract

A divider/combiner amplifier circuit divides input power through a sectored coaxial line to a plurality of longitudinal parallel channels spaced around the circumference of a cylinder; the power in each channel is amplified by a semiconductor device; and the amplified power is combined in another sectored coaxial line. A microwave waveguide connected to the input and output of each amplifying device confines the microwave energy of the operating mode to the longitudinal channel formed by said waveguide. Each waveguide extends longitudinally along the cylinder and each is circumferentially spaced from its neighboring waveguide by a space which forms a cut-off waveguide to the operating mode. In the event of a failure of one or more amplifying elements, the space allows the failure mode to propagate radially to microwave absorbing material where it is absorbed to prevent reflection back into the longitudinal waveguide and thus effectively isolates the failure to provide a gradual deterioration of the amplifier circuit performance with element failure.

Claims

1. A microwave amplifier comprising:

a first waveguide means;

an amplifying means connected to said first waveguide means to form a waveguide amplifier having an input and an output;

a plurality of said waveguide amplifiers having their inputs and outputs connected in parallel;

means adjacent said first waveguide providing a second waveguide between each pair of adjacent first waveguides of said waveguide amplifiers which prevents the operating mode of each of said waveguide amplifiers from propagating through said second waveguide means;

a microwave absorber terminating each second waveguide; and

said absorber absorbing the microwave energy transmitted through said second waveguide from said first waveguide means.

2. The amplifier of claim 1 wherein:

said first waveguide means comprises first and second conductors separated in a first direction by a first mirowave propagation space;

said first and second conductors of each of said adjacent waveguide amplifiers being spaced from each other, respectively, in a second direction transverse to said first direction to form said second waveguide means, said second waveguide means formed by adjacent said first conductors and formed by adjacent said second conductors providing isolation between said first waveguide means and said absorber and acting as a reactive attenuating waveguide beyond cutoff to the operating mode of said first waveguide means and as a transmissive waveguide between said absorber and said first waveguide means of other modes of said first waveguide means.

3. The amplifier of claim 1 comprising in addition:

an input means;

an output means;

means for equally dividing microwave power applied to said input means between said waveguide amplifiers; and

means for combining the output power of each of said waveguide amplifiers and providing said combined power to said output means.

4. The amplifier of claim 3 wherein said means for dividing the input microwave power and combining the output power each comprises a radially stepped impedance transforming coaxial line having spced inner and outer coaxial conductors;

and

said inner and outer conductors having a plurality of slots in the direction of the length of said coaxial line, said inner and outer conductor slots being in radial alignment, said spaced slotted inner and outer conductors being a part of said first waveguide means.

5. The amplifier of claim 4 comprising:

said amplifying means comprising a microwave transmission line comprising first and second radially spaced conductors having the same width as the greatest width of said slotted inner and outer coaxial conductors, respectively;

said first and second radially spaced conductors being adapted to be attached at each end to the inner and outer conductors, respectively, of said input dividing means and said output combining means;

a plurality of amplifying elements; and

said first conductor being interrupted and adapted to be serially connected at said interruption to the input and output terminals of said amplifying means.

6. A microwave amplifier comprising:

a plurality of parallel first microwave waveguides, each first waveguide comprising a pair of conductors separated by a microwave propagation space;

a plurality of microwave amplifier elements;

each first waveguide having an input end and an output end and having one of said amplifier elements connected thereto to amplify microwave energy applied to the output end of the first waveguide;

each of said first waveguides being connected in parallel so that a signal applied to the input end of said parallel connection is amplified in each first waveguide and combined at the output connection of said first waveguides;

each conductor of a pair of conductors spaced to form said first waveguide being laterally spaced from the corresponding conductor of an adjacent first waveguide to provide slots extending along and between said adjacent conductors;

corresponding spaced adjacent conductors forming second and third waveguides, said second and third waveguides each being a reactively attenuating cutoff waveguide to the operating mode and frequency at which amplification takes place in the first waveguide;

said second and third waveguides having microwave absorbers disposed at the slot ends most remote from said microwave propagation space of said first waveguide, said absorbers acting as a termination for said second and third waveguides for microwave energy propagating in said second and third waveguides.

7. The microwave amplifier of claim 6 wherein each of said conductors of said pair of conductors forming each of said first waveguides has a thickness in the direction transverse to said microwave propagation space of said first waveguide, said thickness being sufficient to cause said conductors to provide said second and third waveguides in said thickness direction.

8. A divider/combiner amplifier circuit comprising:

a cylindrical array of a plurality of microwave transmission lines extending longitudinally along the surface of said cylindrical array and circumferentially spaced from each other along said surfaces;

each of said transmission lines comprising a pair of longitudinally extending radially spaced inner and outer electrical conductors;

a plurality of amplifier elements, each connected to one of said transmission lines to amplify microwave energy entering one end of said transmission line and exiting at the other end of said transmission line;

a first and second coaxial line each having inner and outer concentric conductors;

each said coaxial line at one end having a larger diameter of both inner and outer conductors than at the other end, said larger diameter conductors being connected to the ends of said transmission line and being longitudinally slotted to correspond to the circumferential spacing and width of the conductors of said transmission lines;

the other end of said coaxial line being of smaller diameter and unslotted;

microwave absorbers at the radial ends of the circumferential spaces between the inner and outer conductors of said transmission line and said larger diameter coaxial line; and

said circumferential spaces and the radial thickness of said conductor and said larger diameter coaxial line providing waveguides beyond cutoff for attenuating the operating mode of the transmission lines and a propagation space for modes other than the operating mode to cause said microwave absorbers to resistively terminate said waveguide beyond cutoff.

9. The amplifier of claim 8 comprising:

each said coaxial line having a plurality of inner and outer concentric coaxial conductor diameters intermediate those at its ends to provide a stepped coaxial transmission line.

10. The amplifier of claim 9 wherein one of said microwave absorbers comprises a hollow cylindrical absorber whose inner radius is greater than and which surrounds the spaced outer conductors of the array of the plurality of spaced microwave transmission lines and said slotted coaxial lines;

and

the other of said microwave absorber comprises a stepped cylindrical absorber whose diameter is less than that of and which is surrounded by the spaced inner conductors of the array of the plurality of spaced microwave transmission lines and said slotted coaxial lines.

11. The amplifier of claim 10 wherein said microwave absorbers have a resistivity which is less in the immediate vicinity of said slots than at farther removed positions within the absorber to provide a tapered resistor having small reflections of microwve energy incident upon it through said slots.

12. A microwave amplifier comprising:

means for amplifying microwave energy comprising a radially spaced pair of conductors forming a microwave transmission line in the region between said conductors;

means for providing an amplifier element within said transmission line for amplifying microwave energy passing down said line;

a plurality of said transmission lines and corresponding amplifier elements extending longitudinally and spaced from each other along the circumference of a cylinder to form slots spaced along said circumference which extend longitudinally;

a microwave energy absorber at each radial end of said slots; and

said pair of transmission line conductors, each extending radially a sufficient distance and spaced sufficiently closely to form a radially directed transmission line which is beyond cutoff at the operating mode frequency and which allows transmission to said absorbers for modes other than the operating mode.