Directional wire coupler for waveguide tuners and method

Patent metadata

Field	Value
Publication number	US-11233307-B1
Application number	US-202016931021-A
Country	US
Kind code	B1
Filing date	Jul 16, 2020
Priority date	Jul 16, 2020
Publication date	Jan 25, 2022
Grant date	Jan 25, 2022

Abstract

Wideband waveguide to coaxial low loss signal couplers use an electro-magnetic wire loop inserted perpendicularly in a slot in the top cover of the waveguide transmission line. In order to adapt also to various power levels and associated receiver sensitivity, the coupling factor can be modified by controlling the penetration of the wire loop inside the waveguide cavity. Coupling and Directivity are approximately constant and track over the WR bandwidth up to WR-10. A calibration method allows full characterization of a coupler-tuner assembly.

First claim

What is claimed is:

1. A wideband waveguide to coaxial directional signal coupler comprising:
a section of low loss rectangular waveguide transmission line, input port, output port, coupled port and isolated port and an electromagnetic “U” form loop sensor,
said waveguide transmission line having a main axis, wide top and bottom walls and two narrow side walls,
and said U-form electro-magnetic loop sensor having a bottom section and two branches,
wherein
one end of the waveguide transmission line is the input port, and the other end is the output port,

wherein
the loop sensor penetrates contactless perpendicularly into a hole on the top wall of the waveguide transmission line,

and wherein
the bottom section of the U-formed sensor is parallel to the main axis of the waveguide transmission line and its branches extend into forming center conductors of coaxial cables, one of the coaxial cables leading to the coupled port and the other one of the coaxial cables leading to the isolated port.

2. The directional signal coupler of claim 1 ,
wherein the hole is placed on the top wall, centered relative to the main axis.

3. The directional signal coupler of claim 1 ,
wherein the penetration of the U-formed sensor into the hole is modifiable.

4. The directional signal coupler of claim 1 ,
wherein the hole on the top wall is placed offset relative to the main axis.

5. A signal coupler-waveguide tuner assembly comprising:
a cascade of the wideband signal coupler as in claim 1 and a waveguide impedance tuner, both sharing the same waveguide transmission line,
said tuner having input and output ports and comprising:
a remotely controlled reflective tuning probe insertable vertically (perpendicular) and movable horizontally (parallel) to the axis of the waveguide, inside a slot in the waveguide top wall, placed between the input and output ports of the tuner,

wherein
a test port ( 1 ) of the assembly is the input port of the coupler, an output port ( 2 ) of the assembly is the output port of the tuner and the coupling port ( 3 ) and isolated port ( 4 ) of the assembly are the coupled and isolated ports of the signal coupler correspondingly.

6. A calibration method for signal coupler-tuner assembly as in claim 5 , comprising the following steps:
a) connect the coupler-tuner assembly to a pre-calibrated four-port vector network analyzer (VNA) as follows:
a1) the test port of the assembly to a first port of the VNA;
a2) the output port of the assembly to a second port of the VNA;
a3) the coupled port of the assembly to a third port of the VNA;
a4) the isolated port of the assembly to a fourth port of the VNA;
b) measure s-parameters Sij for {i,j}={1,4} for a multitude of horizontal and vertical positions of the tuning probe and save in a calibration file for later use.

7. A calibration method for signal coupler-tuner assembly as in claim 5 ,
wherein a port M is one of the ports 1 to 4 and a port N is one of the ports 1 to 4 of the coupler-tuner assembly,
comprising:
connecting the ports M and N of the coupler-tuner assembly to ports 1 and 2 of a pre-calibrated two-port vector network analyzer (VNA), measuring and saving s-parameters for a multitude of horizontal and vertical positions of the tuning probe as follows:
in a measurement loop
a) connect ports M and N for {M,N}={1,4}, with M≠N, to the VNA ports 1 and 2 ;
b) terminate the remaining ports of the coupler-tuner assembly with characteristic impedance Zo;
c) measure s-parameters Sij for {i,j}={1,2} for the multitude of horizontal and vertical tuning probe positions;
d) save in calibration file MN;
terminate the calibration by concatenating the s-parameters of all files MN and save in a calibration file for later use.

8. The coupler-tuner assembly of claim 5 ,
wherein the slot in the waveguide top wall has a length, parallel to the axis of the waveguide, at least one half of the wavelength at a lowest frequency of operation.

Assignees

• Tsironis Christos

Inventors

• Tsironis Christos

Classifications

• H01P5/183 Primary

  at least one of the guides being a coaxial line · CPC title

• H01P5/04

  with variable factor of coupling · CPC title

• H01P3/06

  Coaxial lines · CPC title

• H01P11/005

  Manufacturing coaxial lines · CPC title