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This article will explain in detail how to use TRL calibration to calibrate waveguides. The content of the article is of high quality, so the editor shares it for you as a reference. I hope you will have some understanding of the relevant knowledge after reading this article.

What I want to share with you today is another way: waveguide Calibration (WAVEGUIDE).

Waveguide is actually a kind of hollow metal tube used to transmit electromagnetic waves. The utility model has the advantages of low conductor loss and dielectric loss, large power capacity, no radiation loss and simple structure and easy to manufacture.

It is used in some of our common household devices, such as microwave ovens. The principle of microwave oven is simply said that microwave energy is generated by magnetron and then input into the furnace chamber through the waveguide, which is composed of metal walls, so the electromagnetic wave is reflected arbitrarily inside. In addition, because of its good high temperature resistance, waveguides are mostly used in radar, communication satellites and high-energy microwave weapons. Radar in a certain frequency to ensure a long range of radiation, so its power is usually very large, the unit is generally kW, so the heat generated by radar radiation is quite large, and the high temperature resistance of waveguide products is just suitable for this. In addition, it can also be connected with the antennas of the transmitter and receiver. The common waveguide structures are parallel planar waveguide, rectangular waveguide, circular waveguide, ridge waveguide and so on.

When the port of the DUT is a waveguide, we cannot calibrate it with a coaxial connector, so we can only use the waveguide calibration. Due to the poor waveguide reflection characteristics of the open circuit, the open circuit standard part is not used. Instead, it is replaced by a gasket with a phase shift of 90 degrees at the central point of the waveguide bandwidth. Usually, the phase shift range of the gasket of 1max 4 λ is from 50 degrees to 120 degrees. The calibration process of gasket with 1x4 λ is usually carried out with short circuit, load and gasket with 1x4 λ, so that enough standard parts can be obtained for traditional single port calibration.

Use the MS46522B of Anli Anritsu for operation instructions:

Click [Calibrate]-> [Manaual Cal]-- > [2-Port Cal]-- > [Modify Cal Setup]

In the pop-up dialog box for modifying calibration parameters, the calibration mode is changed to SSLT, and the calibration end face is a waveguide.

Then click [Edit Cal Params] to pop up the following dialog box to select the waveguide calibrator you need in the Waveguide Kit column, such as WR10 or User Define customization, you can enter the parameters of the waveguide calibrator and save it as a file.

Cutoff frequency is the cutoff frequency of the waveguide calibrator

The Offset short has two lines, the first one is the length of the 0 or 1amp 8 λ circuit breaker, and the next line is the length of the 1 thumb 4 λ or 3 thumb 8 λ circuit breaker, the medium is usually air.

Waveguide calibration kit

Another way to calibrate waveguides is that TRL calibration may be the best and easiest way for two-port networks. It requires only one reflective standard part, usually a short circuit, a path and a transmission line. The gasket of 1x4 λ makes the line ideal because it can easily meet a phase shift of 20 degrees to 160 degrees. In addition, the TRL calibration method has high accuracy and is also suitable for some high-precision products. The straight-through film Thru generally uses 0 length, the reflector Reflect generally uses the short-circuit film, and the Line generally uses 1max 4 λ.

Note: in TRL calibration, the characteristic impedance of the transmission line is the characteristic impedance standard of the system (no matter how much you change the characteristic impedance of the system).

Open the calibration menu of the instrument, select [LRL/LRM] in the Calibration Type column, which means TRL, and Line Type select [Waveguide].

Clicking "Edit Cal Params" will bring up the following dialog box:

Device Length input 0 pass-through

Device Length Match chooses the physical length of 1 to 4 wavelength straight-through chip

Cutoff frequency is input according to the actual situation of the calibrator.

After the input of the calibration parameters, you can select [Save Kit] for subsequent use, which has the advantage that you do not need to re-enter it next time.

Calibrate the reflection of the port with a short circuit piece

Device 1 Line 0 pass-through is to directly connect both ends of the coaxial wavelength converter.

Device 2 Line is the interconnection of 1amp 4-wavelength straight-through wafers (usually screwed during operation)

Finally, click [Done] to complete the calibration.

On how to use TRL calibration method for waveguide calibration is shared here, I hope the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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