JPS6214722Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a waveguide low-pass transducer in which the dimension of the E surface of the waveguide is narrowed in order to prevent the propagation of higher-order modes.

A conventional Watsuful iron waveguide low pass resonator is shown in FIGS. 1a-c. a is a cross-sectional view taken along line A-A', b is a side cross-sectional view taken along line B-B', and c is a front view. In the figure, 1 indicates a low-pass waveguide resonator section, 2 indicates an impedance conversion section, and 3 indicates an opening end of an input/output waveguide.

In order to prevent the propagation of higher-order modes, the Watsuful iron type low-pass waveguide has a very small length of the waveguide E (electric field) surface direction (height direction) in the low-pass waveform resonator section. There is. That is, by reducing the length in the E-plane direction with respect to the propagation mode excited in the E-plane direction, the cutoff frequency of the propagation mode in this direction is increased, and propagation of higher-order modes is blocked.

Therefore, the smaller the length in the E-plane direction, the higher the cutoff frequency becomes, and higher-order mode propagation is blocked over a wide band.

However, waveguide circuit components connected to the input/output opening ends generally use waveguides standardized by JIS or other standards. Therefore, since the length of the resonator part of the low-pass waveguide is usually different from the length in the E-plane direction of the waveguide, the first
As shown in the figure, it is configured with an impedance conversion section 2.

For example, for a general waveguide, b/a=1/2
(a: length in the waveguide H-plane direction (lateral direction), b: length in the waveguide E-plane direction). Therefore, it is necessary to use the impedance conversion section 2 in order to connect the circuit components before and after the circuit components in an electrically matched state.

In other words, since the length of the low-pass wave resonator section 1 in the E-plane direction is smaller, the impedance is lower than that of the circuit components before and after it, so that λ
Impedance matching with an external circuit must be achieved using a g/4 step converter or a taper converter.

The smaller the length of the resonator section in the E-plane direction, the more gradually it is necessary to transform the impedance, which requires a step transformer with more stages or a longer taper transformer, making the low-pass waveformer in step 2 larger. There are drawbacks.

Also, the smaller the length in the E plane direction,
Since the concentration of the electric field on this portion increases, the impedance matching deteriorates significantly due to minute dimensional errors. That is, since strict dimensional accuracy is required, it takes a lot of time to manufacture and is not suitable for mass production.

The purpose of this invention is to provide an excellent waveguide low-pass waveguide that is mechanically smaller and lighter than conventional ones, and that has good characteristics in large quantities at low cost. .

In order to achieve the above object, the present invention utilizes a waveguide H in a waveguide low-pass waver that blocks the propagation of harmonics by narrowing the length of the waveguide in the E-plane direction.
(Magnetic field) The feature is that the length in the plane direction is also small.

As a result, the drawbacks of the conventional method are eliminated, and a waveguide low-pass transducer which is small in size and highly suitable for mass production as will be described in detail later can be obtained, and its utility value is high in high frequency circuits.

The present invention will be explained in more detail below with reference to the drawings.

FIG. 2 shows an embodiment of the Watsuful iron waveguide low-pass waveguide according to the present invention.
A' is a cross-sectional view, b is a BB' side sectional view, and c is a front view. In the figure, 11 is a resonant section, 12 is a step impedance conversion section, and 13 is an input/output waveguide opening end, which corresponds to 1, 2, and 3 in FIG.

Conventionally, as shown in FIG. 1, the length of the waveguide in the E-plane direction has been made very narrow over the entire H-plane in order to prevent the propagation of higher-order modes. Therefore, as an impedance converter, it was necessary to make impedance matching with the resonator part by making the E-plane length b of the opening end of the low-pass wave device on the resonator part side extremely small. On the other hand, in the impedance conversion section, impedance conversion must be performed gradually in order to achieve broadband matching. That is, the impedance conversion ratio is E
Since it is determined by the ratio of surface lengths, the smaller the conversion ratio, that is, the smaller the change in length in the E-plane direction, the more impedance matching is possible with a λg/4 step transformer or a short taper transformer with fewer stages. It means that.

The present invention requires a high impedance conversion ratio as an impedance conversion section since the resonator section of a conventional waveguide low-pass waveguide has a very low impedance at the input/output opening end of the waveguide. In order to eliminate the disadvantage of requiring a multi-stage λg/4 step transformer or a long taper transformer, instead of reducing the E-plane length over the entire length of the resonator waveguide in the H-plane direction. , 14 in order to reduce the H-plane dimension of the resonator part waveguide to a'<a, as shown in FIG.

That is, by setting it to a', concentration in the direction of the magnetic field increases, exhibiting inductivity and resulting in high impedance. Therefore, since the impedance is higher than when the E-plane length is made smaller over the entire length in the H-plane direction, matching may be achieved using an impedance conversion section with a small impedance conversion ratio. That is, the E-plane length _b'T of the connection opening end of the impedance converter 12 on the resonator section 11 side can be made wider than the conventional E-plane length _bT . Therefore, the impedance conversion section 12 of the low-pass waveform is equivalent to the conventional low-pass waveform by using a λg/4 step transformer or a shorter taper transformer with fewer stages than the conventional low-pass waveform. It is possible to obtain the consistency of

Furthermore, since the length of the E-plane is larger than that of the conventional low-pass wave generator, the concentration ratio of the electric field is also reduced. For this reason, dimensional accuracy is relaxed compared to conventional products that required very strict precision. Note that even if the H-plane length of the low-pass wave device resonator section is made small, the electrical design of the low-pass wave device can be designed in the same way as a conventional low-pass wave device. Therefore, electrical performance does not deteriorate.

Here, we will explain using a Watsuful iron type low-pass wave generator designed for the 20 GHz band as an example. In the case of the conventional product, a taper transformer is used as the impedance conversion part, and the resonator part side input/output opening end E surface dimension b
When _T = 2mm (a = 12.954mm), the overall dimensions are
74.32 mm (number of teeth in the propagation direction: 5), whereas according to the present invention, by setting a' = 8.12 mm, b' _T = 4.58 mm, and the overall dimension is 25.36 mm (number of teeth in the propagation direction). Number of teeth: 5, one-stage λg/4 step transformer is used as the impedance converter.)
Therefore, the size is reduced to about one-third.

As described above, according to the present invention, it is possible to obtain an excellent waveguide low-pass wave device that is small and lightweight, and is highly suitable for mass production.

As detailed above, in a waveguide low-pass waveguide that blocks the propagation of higher-order modes by reducing the length of the E-plane of the waveguide, simply by reducing the length of the H-plane of the waveguide, By increasing the impedance of the low-pass wave device resonator section and reducing the impedance conversion ratio, the dimensions of the impedance transformation section are reduced, which has the advantage of making the wave device smaller and lighter. Also, in the production of the corrugated device,
Conventionally, the manufacturing dimensional accuracy of the low impedance part was very strict, but compared to this, there is an advantage that it is easier to ensure dimensional accuracy because the impedance is higher than the conventional one. In other words, it is possible to produce a small, lightweight, and inexpensive waveguide low-pass waveguide, and we are confident that it will contribute to the development of this type of circuit components.

In the above explanation, the Watsuful iron type low-pass wave transducer was explained as an example, but it is clear that the corrugated type also has the above-mentioned advantages. The present invention is applicable to all waveguide low-pass wave devices that block the propagation of higher-order modes by reducing the length of the E-plane of the waveguide.

[Brief explanation of the drawing]

FIG. 1 shows a conventional Watsuful iron waveguide low-pass waveguide, in which a is a cross-sectional view, b is a side sectional view, and c is a front view. FIG. 2 is a diagram showing an embodiment of the Watsuful iron waveguide and low-pass waveguide according to the present invention, and ac corresponds to the diagrams in FIGS. 1 a to 1c. In the figure, 11 is a low-pass waveguide resonator, 12 is an impedance converter, and 13 is an input/output waveguide opening.

Claims (1)

[Scope of utility model registration request] In a waveguide low-pass waveguide that includes an impedance conversion section, a resonance section, and an input/output aperture and blocks propagation of higher-order modes, the length of the waveguide in the electric field and magnetic interface direction is at least the resonance section. A waveguide low-pass reactor waveguide, characterized in that the input/output opening is shorter than that of the input/output opening.