CN111342171B

CN111342171B - Non-contact waveguide flange

Info

Publication number: CN111342171B
Application number: CN202010123774.9A
Authority: CN
Inventors: 吴昌英; 刘育杰; 高峰
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2020-02-27
Filing date: 2020-02-27
Publication date: 2021-05-07
Anticipated expiration: 2040-02-27
Also published as: CN111342171A

Abstract

The invention relates to a non-contact waveguide flange, belonging to the technical field of microwaves; the end surface of the waveguide flange is provided with a runway-shaped groove and a straight groove, and the runway-shaped groove is arranged at the periphery of the waveguide port; the straight groove is arranged between the runway-shaped groove and the waveguide port and is positioned on the central line of the long edge of the waveguide port, two ends of the straight groove are communicated with the runway-shaped groove, and the middle section is positioned in the waveguide port; the depth of the straight groove, the depth of the runway-shaped groove and the radial distance from the runway-shaped groove to the waveguide port are all within the range of one eighth to three eighths of wavelength. By adopting the runway-shaped groove and the straight groove, the insertion loss is less than 0.1dB under the condition that the waveguide flange is not in contact, and the working bandwidth of the non-contact waveguide flange is expanded to the whole waveguide frequency band.

Description

Non-contact waveguide flange

Technical Field

The invention belongs to the technical field of microwaves, and particularly relates to a non-contact waveguide flange.

Background

When two waveguides are connected by a waveguide flange, the two waveguide flanges are usually aligned by pins and screwed together, and the two waveguide flange faces cannot rust, which would result in reflection or radiation loss, in order to achieve good electrical contact. In some situations, such as waveguide switches, microwave measurements, etc., where the waveguide needs to be switched frequently, the alignment and fastening of the waveguide flange is very cumbersome.

Early quarter wave choke waveguide flanges, while overcoming the poor contact problem caused by rusting of the waveguide flange, still required pin alignment and screw tightening. The document "Budhaditya Pne, Ryohei Naruse, Hirobumi Saito, Jiro Hirokawa, Vinay Ravindra, Prilando Riziki Akbar. Robust contact non-critical hook wing for wide band Waveguide applications, IEEE TRANSACTIONS MICROWAVE THEORY AND TECHNIQUES, VOL.67, NO.3, pp.861-867,2019" proposes a non-contact Flange form which allows Waveguide switching to be performed very easily. However, the waveguide flange has a narrow bandwidth, cannot cover the whole waveguide frequency band, and the insertion loss reaches 0.5dB in the working frequency band. In addition, the insertion loss is sensitive to the alignment error of the waveguide flange in the long side direction, and the error cannot exceed 0.2mm in an X wave band.

Disclosure of Invention

The technical problem to be solved is as follows:

in order to avoid the defects of the prior art, the invention provides the non-contact waveguide flange, and the runway-shaped groove and the straight groove are introduced into the waveguide flange, so that the working bandwidth of the non-contact waveguide flange is expanded, the insertion loss in the whole waveguide frequency band is reduced, and the sensitivity of the insertion loss to the waveguide flange quasi-error is weakened.

The technical scheme of the invention is as follows: a contactless waveguide flange, characterized by: the end surface of the waveguide flange is provided with a runway-shaped groove and a straight groove, and the runway-shaped groove is arranged at the periphery of the waveguide port; the straight groove is arranged between the runway-shaped groove and the waveguide port and is positioned on the central line of the long edge of the waveguide port, two ends of the straight groove are communicated with the runway-shaped groove, and the middle section is positioned in the waveguide port;

the depth of the straight groove, the depth of the runway-shaped groove and the radial distance from the runway-shaped groove to the waveguide port are all in the range of one eighth to three eighths of wavelength.

The further technical scheme of the invention is as follows: the depth of the straight groove, the depth of the runway-shaped groove and the radial distance from the runway-shaped groove to the waveguide port are all quarter wavelengths.

Advantageous effects

The invention has the beneficial effects that: the non-contact waveguide flange provided by the invention adopts the runway-shaped groove and the straight groove to ensure that the insertion loss is less than 0.1dB under the condition that the waveguide flange is not in contact, and the working bandwidth of the non-contact waveguide flange is expanded to the whole waveguide frequency band; when the waveguide flange has alignment errors, the adopted straight groove can inhibit the increase of the surface current of the waveguide flange, and the current distribution on the waveguide flange is consistent with the surface current distribution of the waveguide flange without the alignment errors, so that the sensitivity of the insertion loss to the alignment errors of the waveguide flange is weakened, and the insertion loss is less than 0.1dB when the alignment errors of the waveguide flange in the X waveband are within 0.4 mm.

Drawings

FIG. 1 is an oblique view of a non-contacting flange with a rectangular waveguide.

Fig. 2 is a right side view of a non-contact flange with a rectangular waveguide.

Fig. 3 is a cross-sectional view a-a of a non-contacting flange with a rectangular waveguide.

Fig. 4 is an oblique view of the non-contact flange and a conventional flat flange when connected.

Fig. 5 is a front view of a non-contact flange and a conventional flat flange when connected.

FIG. 6 is a top view of a non-contact flange and a conventional flat flange with long edge alignment errors.

FIG. 7 is a front view of a non-contact flange and a conventional flat flange in the presence of short edge misalignment.

Fig. 8 is a characteristic curve of the change in S21 caused by the gap Δ z.

Fig. 9 is a characteristic curve of the change in S21 caused by the alignment error Δ x.

Fig. 10 is a characteristic curve of the change in S21 caused by the alignment error Δ y.

Fig. 11 shows the surface current distribution of a waveguide flange with only racetrack slots and no alignment error.

Fig. 12 is a surface current distribution of a waveguide flange with only racetrack slots and alignment error.

Fig. 13 is a surface current distribution of a waveguide flange with straight slots added and no alignment error.

Fig. 14 is a surface current distribution of a waveguide flange with added straight slots and alignment error.

Description of reference numerals: 1-rectangular waveguide, 2-waveguide port, 3-contactless flange, 31-racetrack groove, 32-straight groove and 4-conventional flat flange.

Detailed Description

The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

As shown in fig. 1-3, the present invention provides a non-contact waveguide flange, in which a racetrack groove and a straight groove are formed in an end surface of the waveguide flange; the runway-shaped groove surrounds the waveguide port, is spaced between one eighth wavelength and three eighths wavelength away from the waveguide port, and the depth of the runway-shaped groove takes a value between one eighth wavelength and three eighths wavelength; the straight groove is vertical to the long edge of the waveguide port and is positioned on the central line of the long edge of the waveguide port, and the straight groove is positioned inside the runway-shaped groove and connected with the two edges of the runway-shaped groove; the non-contact waveguide flange and the conventional flat flange provided by the invention are separated by a certain distance, and when no alignment error exists, the runway-shaped groove can inhibit electromagnetic waves from leaking from a gap between the non-contact waveguide flange and the conventional flat flange; the non-contact waveguide flange and the conventional flat flange provided by the invention are separated from each other within a certain distance, when alignment errors exist, the adopted straight groove can inhibit the increase of the surface current of the waveguide flange, and the current distribution on the waveguide flange is consistent with the surface current distribution on the waveguide flange when no alignment errors exist, so that the sensitivity of insertion loss to the alignment errors of the waveguide flange is weakened. The specific value of the wavelength size of one eighth to three eighths is based on the optimization of actual simulation.

Example (b):

in the present embodiment, the rectangular waveguide 1 is a standard waveguide of model BJ100, and operates in the X-band. A racetrack groove 31 and a straight groove 32 are located in the contactless flange 3. The racetrack groove 31 has a depth t of 6.5mm, a width w of 4.9mm, a length l of the straight portion of 6.9mm and a distance d of 6mm from the waveguide mouth 2. The width u of the straight groove 32 is 2mm and the depth s is 3.5 mm.

When the non-contact flange 3 and the conventional flat flange 4 are placed as shown in fig. 4 and 5, the non-contact flange 3 and the conventional flat flange 4 are not in contact with each other, and there is a gap therebetween, the distance of which is Δ z. The non-contact with the race-track groove 31 in the flange 3 can suppress leakage of electromagnetic waves from the gap between the two flanges. Fig. 8 shows the characteristic of the change in S21 caused by the gap Δ z over the entire X band. It can be seen that the insertion loss is less than 0.1dB when Δ z does not exceed 2.4 mm.

In the case where Δ z is 1mm, when an alignment error occurs in the two flanges, the straight groove 32 in the non-contact flange 3 can suppress leakage of electromagnetic waves from the gap between the two flanges. Fig. 6 shows the case where the non-contact flange 3 and the conventional flat flange 4 have an alignment error Δ x along the long side of the waveguide port 2. As can be seen from fig. 9, when Δ x does not exceed 2.4mm, the insertion loss is less than 0.1 dB. Fig. 7 shows the case where the non-contact flange 3 and the conventional flat flange 4 have an alignment error Δ y along the short side of the waveguide port 2. As can be seen from fig. 10, when Δ y does not exceed 0.4mm, the insertion loss is less than 0.1 dB.

To further illustrate the beneficial effects of the straight slot 32 of the present invention, fig. 11-14 show the surface current distribution of the waveguide flange 3. Fig. 11 shows the surface current distribution of the waveguide flange 3 when only the racetrack groove 31 is present and there is no alignment error, and fig. 12 shows the surface current distribution of the waveguide flange 3 when only the racetrack groove 31 is present and there is an alignment error. As can be seen from fig. 11 and 12, when an alignment error occurs, the surface current of the waveguide flange 3 significantly increases, so that the insertion loss performance is affected. Fig. 13 shows the surface current distribution of the waveguide flange 3 when the straight groove 32 is added and there is no alignment error, and fig. 14 shows the surface current distribution of the waveguide flange 3 when the straight groove 32 is added and there is an alignment error. As can be seen from fig. 13 and 14, when an alignment error occurs, the surface current of the waveguide flange 3 is kept uniform, and the straight groove 32 effectively suppresses an increase in the surface current of the waveguide flange 3 when an alignment error occurs, so that the insertion loss performance is also kept uniform.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.

Claims

1. A contactless waveguide flange, characterized by: the end surface of the waveguide flange is provided with a runway-shaped groove and a straight groove, and the runway-shaped groove is arranged at the periphery of the waveguide port; the straight groove is arranged between the runway-shaped groove and the waveguide port and is positioned on the central line of the long edge of the waveguide port, two ends of the straight groove are communicated with the runway-shaped groove, and the middle section is positioned in the waveguide port;