JPS6329281Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a waveguide type variable phase shifter used in microwave circuits and millimeter wave circuits.

Waveguide phase shifters include phase shifters for delaying the phase (hereinafter referred to as phase-lag phase shifters) and phase shifters for advancing the phase (phase-advancing phase shifters). .

The present invention relates to a variable phase advance phase shifter, and particularly proposes a phase shifter for obtaining a small amount of phase with high accuracy in the millimeter wave band.

Conventionally, a slow phase shifter uses a dielectric material as a phase shift element, and changes the position of the dielectric material in the waveguide or the insertion length of the dielectric material into the waveguide, making it relatively easy to use. A variable phase shifter was constructed in the prior art, but on the other hand, a phase advance phase shifter did not have a phase shift element to easily change the phase amount.

FIG. 1 is a perspective view showing an example of a conventional phase advance phase shifter. In the figure, 1 is a waveguide, and 2 is a plurality of inductive irises provided within the waveguide.

The inductive iris 2 is well known for its ability to advance the phase of transmitted waves, and by adjusting the shape, arrangement, etc. of the iris, it is possible to obtain the required phase amount without reflection. .

FIG. 2 is a perspective view showing another conventional phase advance phase shifter. In the figure, 3 is a rectangular waveguide with a protrusion 4 provided on its narrow surface (wall surface parallel to the main electric field component) to guide the waveguide. This is a modified waveguide with a narrower waveguide width.

In the modified waveguide 3 with a narrower waveguide width, the wavelength within the waveguide portion provided with the protrusion 4 becomes longer.
It is clear that the phase advances compared to before deformation, and by adjusting the shape of the protrusion 4, the required phase amount can be obtained without reflection.

However, this conventional means for advancing the phase has the disadvantage that the amount of phase cannot be changed continuously.

In order to eliminate these drawbacks, this invention provides a protruding movable plate on the narrow side of a rectangular waveguide, and will be described in detail below with reference to the drawings.

FIG. 3 is a perspective view of a variable phase shifter showing an embodiment of this invention, and in the figure, 5 is a modified waveguide 3.
It is a protruding movable plate that is attached to a narrow surface where no protrusion 4 is provided and can move in the tube axis direction.

4 and 5 are diagrams used to explain the phase advance variable phase shifter, and FIG. 4 shows that the movable plate 5 is a protrusion of the deformed waveguide 3 in the phase advance variable phase shifter. FIG. 5 is a sectional view showing that the movable plate 5 is arranged apart from the protrusion 4 of the deformed waveguide 3 in the variable phase shifter. FIG. 3 is a cross-sectional view showing that it has entered the pipe section.

Here, for convenience of explanation, the protrusion 4 of the deformed waveguide 3
The width of the waveguide in the part without the protrusion 4 is a ₁ , the width of the waveguide in the part with the protrusion 4 is a ₂ , and the axial length of the protrusion 4 is
Let l ₂ be the width of the waveguide provided with the movable plate 5 as a ₃ , and let the axial length of the movable plate 5 be l ₃ .

Furthermore, in FIG. 5, the width of the waveguide at the portion where the protrusion 4 and the movable plate 5 are in the same cross section is a ₄ , and the axial length is l ₄
shall be.

Note that, for the sake of simplification of explanation, the projection 4 and the movable plate 5 shown in FIGS. 4 and 5 are not provided with a tapered portion.

In such a phase shifter, when the movable plate 5 is moved from the state shown in FIG. 4 to the state shown in FIG.
The amount of phase change shown in the equation can be obtained. (Φ assumes that the phase advance is positive.) Φ＝Φ ₂ −Φ ₁ …(1) Φ ₁ = −2πl ₂ /λg ₂ −2πl ₃ /λg ₃ …(2) Φ ₂ = −2π(l ₂ − l ₄ )/λg ₂ −2πl ₄ /λg ₄ −2π(l ₃ −l ₄ )/λg ₃ −2πl ₄ /λg ₁ …(3) λg is the tube wavelength, λo is the free space wavelength, Now, substituting equations (2) and (3) into equation (1), we get
Φ is Φ=2πl ₄ (1/λg ₂ +1/λg ₃ -1/λg ₄ -1/λg ₁
)…(8), and from the relationship a ₄ = a ₂ + a ₃ − a ₁ …(9), when a _{2 <} a 1, a 3 < a 1, numerical calculation shows that Φ>0…(10) is obtained.

Therefore, this phase shifter can obtain a phase advance proportional to _l4 .

In addition, in the millimeter wave band, by adjusting the dimensions of a ₂ and a ₃ , it is easy to reduce the phase amount per unit length with respect to l ₄ , and therefore,
The phase can be adjusted with high precision.

In addition, although the rectangular waveguide has been described above, this invention is not limited to this and may be used for circular waveguides and other transmission paths.

As described above, in the phase shifter according to this invention, a movable plate that protrudes from the protruding waveguide portion on the wall surface of the waveguide is provided separately, and by moving it, variable phase advance and phase shift can be achieved. This has the advantage that the phase can be adjusted with high precision because it can be used as a container and it is easy to reduce the amount of phase change that occurs per unit length.

[Brief explanation of drawings]

1 and 2 are perspective views of a conventional phase shifter, FIG. 3 is a perspective view of a phase shifter according to this invention, and FIG. 4 is a perspective view of a conventional phase shifter.
5 are sectional views of the phase shifter according to this invention. In the figure, 1 is a waveguide, 2 is an inductive iris, 3 is a deformed waveguide, 4 is a projection, and 5 is a movable plate. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

Claims (1)

[Scope of utility model registration request] It is fixed to one of two opposing wall surfaces that are approximately parallel to the direction of the main electric field determined by the electric field distribution in the cross section of the waveguide, and has a long protrusion in the tube axis direction, and the other surface has a tube axis. can move in the direction
A phase shifter characterized in that a movable plate is provided which is long in the tube axis direction, and the movable plate is configured to be movable to a waveguide portion provided with the protrusion.