Wave transmission lines and networks – Coupling networks – Balanced to unbalanced circuits
Reexamination Certificate
1999-12-23
2003-06-17
Lee, Benny (Department: 2817)
Wave transmission lines and networks
Coupling networks
Balanced to unbalanced circuits
C333S033000
Reexamination Certificate
active
06580335
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a waveguide-transmission line transition for converting electrical power in a microwave or millimeter-wave band.
2. Description of the Related Art
Japanese Patent Application Laid-Open (kokai) No. 10-126114 (Feeder Transition) discloses a known type of waveguide-transmission.line transition capable of effecting mutual conversion between power transmitted through a waveguide and power transmitted through a strip line.
FIG. 22
is a.perspective view of a waveguide-transmission line transition
300
according to a prior art technique;
FIG. 23A and 23C
are cross-sectional views of the transition
300
; and
FIG. 23B
is a plan view of the transition
300
.
A strip line
3
is provided on one surface of a dielectric substrate
4
, and a grounding metal layer
5
—which is to be connected to an opening surface of a waveguide
2
—is provided on the other surface of the dielectric substrate
4
. The dielectric substrate
4
is fixedly sandwiched between a short-circuiting waveguide block
9
and the waveguide
2
. Since a high efficiency of the transition is obtained when the strip line
3
is disposed at a position within the waveguide
2
at which a strong electric field is present, the distance between the short-circuiting surface of the short-circuiting waveguide block
9
and the strip line
3
is set to about ¼ of the wavelength x in the waveguide.
When the conventional transition
300
is used to connect the waveguide
2
to a microwave or millimeter-wave circuit, the short-circuiting waveguide block
9
vertically projects from a substrate on which microwave or millimeter-wave circuit is formed, because the strip line.
3
is located on the same plane as that of the substrate of the microwave or millimeter-wave circuit. Especially, when such a transition is used for conversion in a microwave band, the height of the projection (&lgr;/4) of the short-circuiting waveguide block
9
sometimes exceeds 2 cm, which hinders miniaturization of the microwave circuit.
Meanwhile, when the conventional transition is used for conversion in a millimeter wave band, the matching characteristics of the transition
300
deteriorate when a slight positional shift is produced among the waveguide
2
, the short-circuiting waveguide block
9
, and the strip line
3
. Therefore, in order to obtain a high efficiency of the transition, the waveguide
2
, the short-circuiting waveguide block
9
, and the strip line
3
must be fixed with positional accuracy as high as about {fraction (1/100)} mm.
However, the above-described conventional structure makes it difficult to fix the short-circuiting waveguide block
9
and the waveguide
2
, among other components, with such high accuracy, and therefore has been a main cause of hindering mass production of waveguide-transmission line transitions.
SUMMARY OF THE INVENTION
The present invention was accomplished in order to solve the above-described problems, and an object of the present invention is to provide a waveguide-transmission line transition which has a high efficiency of the transition and a reduced size, and which can easily be produced on a large scale.
Another object of the present invention is to provide a waveguide-transmission line transition having a structure which prevents variation (deterioration) of properties such as a resonant frequency, which would otherwise occur due to variation in waveguide width among mass-produced waveguides.
According to a first aspect of the present invention, there is provided a waveguide-transmission line transition which includes a strip line projecting inward on an opening surface of a waveguide to be parallel to the opening surface and which effects mutual conversion between power transmitted through the waveguide and power transmitted through the strip line, comprising a plate-shaped short-circuiting member shielding the opening surface of the waveguide and having a slit in which the strip line is disposed; a matching element disposed within the waveguide, the matching element being substantially parallel to and separated by a predetermined distance from the short-circuiting member; and a dielectric member disposed between the short-circuiting member and the matching element, wherein the strip line disposed in the slit and the matching element are disposed in proximity to each other to be electromagnetically coupled.
According to a second aspect of the present invention, as is concretely shown in a first embodiment, the short-circuiting member is a short-circuiting plate having a slit in which the strip line is disposed; and the dielectric member comprises at least a first dielectric substrate which is inserted into the slit and which has the strip line disposed on its outer surface.
According to a third aspect of the present invention, the transition according to the second aspect is further characterized in that the dielectric member comprises a second dielectric substrate which is joined to reverse surfaces of the short-circuiting plate and the first dielectric substrate and on which the matching element is formed.
According to a fourth aspect of the present invention, as is concretely shown in a second embodiment, the dielectric member is formed of a first dielectric substrate shielding the opening surface of the waveguide and a second dielectric substrate which is joined to a reverse surface of the first dielectric substrate and on which the matching element is formed; and the short-circuiting member is formed of a short-circuiting metal layer formed on an outer surface of the first dielectric substrate and having a slit, wherein the strip line is disposed in the slit of the short-circuiting metal layer.
According to a fifth aspect of the present invention, as is concretely shown in a third embodiment, the dielectric member is formed of a dielectric substrate which shields the opening surface of the waveguide and which has the matching element on its reverse surface; and the short-circuiting member is formed of a short-circuiting metal layer formed on an outer surface of the dielectric substrate and having a slit, wherein the strip line is disposed in the slit of the short-circuiting metal layer.
According to a sixth aspect of the present invention, the dielectric substrate or the first dielectric substrate has on its reverse surface, opposite the surface where the strip line is formed, a grounding metal layer which comes into contact with an end face of a side wall at the opening surface of the waveguide.
According to a seventh aspect of the present invention, the short-circuiting metal layer and the grounding metal layer are electrically connected with each other by means of through-holes.
According to an eighth aspect of the present invention, the strip line is disposed in each of a plurality of slits formed in the short-circuiting member.
According to a ninth aspect of the present invention, the grounding metal layer is formed and disposed such that a region surrounded by an inner circumference of the grounding metal layer on the reverse surface of the second dielectric substrate or the dielectric substrate is completely included in a region surrounded by an inner wall of the waveguide.
According to a tenth aspect of the present invention, the center of the matching element is offset from the center of the waveguide by a predetermined distance &Dgr; along the longitudinal direction of the strip line toward the direction of projection of the strip line.
According to an eleventh aspect of the present invention, the predetermined distance &Dgr; falls within a range of about 1 to 4% the narrower wall-to-wall distance P of the waveguide.
According to a twelfth aspect of the present invention, at least two through-holes are disposed on opposite sides of an entrance of the slit; and the distance between the through-holes is less than double the width of the strip line.
According to a thirteenth aspect of the present invention, impedance adjustment is performed through adjustment of a length over which the strip
Iizuka Hideo
Nishikawa Kunitoshi
Sakakibara Kunio
Sato Kazuo
Watanabe Toshiaki
Kabushiki Kaisha Toyota Chuo Kenkyusho
Lee Benny
LandOfFree
Waveguide-transmission line transition having a slit and a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Waveguide-transmission line transition having a slit and a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Waveguide-transmission line transition having a slit and a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3115968