Communications: radio wave antennas – Antennas – Wave guide type
Reexamination Certificate
2001-02-13
2002-07-30
Phan, Tho (Department: 2821)
Communications: radio wave antennas
Antennas
Wave guide type
C343S772000, C343S775000, C333S02100R
Reexamination Certificate
active
06426729
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a conductive-transmission-line waveguide converter, a microwave reception converter and a satellite-broadcast reception antenna, which are well suitable for reception of a broadcast transmitted as a cross-polarized wave modulated by broadcasted signals of a group of channels having horizontally polarized and vertically polarized waves different from each other such as a CS broadcast and an Astra satellite broadcast of Europe.
A CS broadcast and an Astra satellite broadcast of Europe are each a satellite broadcast using a cross-polarized wave modulated by signals of a group of broadcasting channels with horizontally polarized and vertically polarized waves different from each other.
Comprising a parabola-shaped reflecting mirror and a converter unit, a satellite-broadcasting reception antenna is also referred to as simply a parabola antenna. The converter unit is also referred to as a microwave reception converter. In a parabola antenna for receiving such a cross-polarized wave, the parabola-shaped reflecting mirror reflects a wave transmitted by a satellite to a converter unit. In the converter unit, the reflected wave is introduced into a waveguide by way of a horn-like portion. A polarized-wave splitter splits the wave led to the inside of the waveguide into horizontally-polarized-wave and vertically-polarized-wave components. The horizontally-polarized-wave and vertically-polarized-wave components are each subjected to frequency down conversion in a down converter for producing signals having respective frequencies predetermined for a group of channels. The signals resulting from the frequency down conversion are then supplied to a television tuner.
In the case of the satellite-broadcasting reception antenna including a polarized-wave splitter for splitting a cross-polarized wave into horizontally-polarized-wave and vertically-polarized-wave components, however, the polarized-wave splitter must be provided at a location in the middle of an electromagnetic-wave transmission route inside the waveguide. Thus, the length of the waveguide needs to be increased in the longitudinal direction. As a result, there is raised a problem of a large size. In addition, since a component dedicated to serve as a probe for taking in a horizontally polarized wave is required separately from a component dedicated to serve as a probe for taking in a vertically polarized wave, there is also raised a problem of a rising manufacturing cost.
As a conventional conductive-transmission-line waveguide converter employed in the converter unit, there has been proposed a conductive-transmission-line waveguide converter wherein a conversion unit of a microstrip line is provided inside a waveguide to separate and take in horizontally-polarized-wave and vertically-polarized-wave components from an electromagnetic wave transmitted as a cross-polarized wave.
FIG. 1
is a diagram showing a cross section of the conventional conductive-transmission-line waveguide converter. As shown in the figure, in this conductive-transmission-line waveguide converter, on one side of the longitudinal direction of a cylindrical waveguide
1
, a feed horn
2
is provided. On the other side of the longitudinal direction of the cylindrical waveguide
1
, a wiring board
3
is provided, being oriented in a direction perpendicular to the longitudinal direction of the waveguide
1
. The wiring board
3
is typically a planar board made of a dielectric such as Teflon or the like. The wiring board
3
is provided in such a way that a portion thereof is located on a transmission path of an electromagnetic wave inside the waveguide
1
. The feed horn
2
is veiled with a protection cover
4
to prevent dust or the like from entering the inside of the waveguide
1
. The wiring board
3
is accommodated in a shield case
5
.
Let the surface of the wiring board
3
on the side of the feed horn
2
be the front surface. In this case, on the back-surface side of the wiring board
3
, an earth conductor is provided for forming a circuit implemented by a microstrip line. A probe unit
7
is created in an area on of the front surface of the wiring board
3
facing the internal space of the waveguide
1
. The probe unit
7
is used for separating horizontally-polarized-wave and vertically-polarized-wave components from an eletromagnetic wave propagating inside the waveguide
1
and taking in the separated wave components.
Broadcasting-channel signals represented by the horizontally polarized and vertically polarized waves taken in by the probe unit
7
are converted into signals having respective frequencies predetermined for a group of channels by a down-converter circuit
8
created on the front-surface of the wiring board
3
. The signals with the predetermined frequencies are supplied to a television tuner by way of a connector
6
.
FIG. 2
is an explanatory diagram showing the probe unit
7
formed on the front surface of the wiring board
3
. To put it in detail, in an area on the front surface of the wiring board
3
, an earth conductor
3
c
is created. The area is an area in contact with the edge surface of the waveguide
1
. In addition,
2
conductor lines
3
a
and
3
b
with all but equal widths are created on the wiring board
3
along axis lines Lx and Ly, which both pass through a cross point O of the wiring board
3
and the longitudinal axis of the waveguide
1
, being orientated perpendicularly to each other.
Thus, an end portion of the conductor line
3
a
and an end portion of the conductor line
3
b
are placed on the wiring board
3
in the internal space of the waveguide
1
. As shown in
FIG. 2
, the lengths of the end portion of the conductor line
3
a
and the end portion of the conductor line
3
b
on the wiring board
3
inside the waveguide
1
are slightly smaller than the inner radius of the waveguide
1
. The end portion of the conductor line
3
a
and the end portion of the conductor line
3
b
on the wiring board
3
inside the waveguide
1
are used respectively as a probe P
1
for taking in a horizontally polarized wave and a probe P
2
for taking in a vertically polarized wave.
As shown in
FIG. 2
, the center line of the probe P
1
on the conductor line
3
a
coincides with the axis line Lx and the center line of the probe P
2
on the conductor line
3
b
coincides with the axis line Ly. The center line of the probe P
1
is a line passing through the middle of each transversal line segment of the probe P
1
. By the same token, the center line of the probe P
2
is a line passing through the middle of each transversal line segment of the probe P
2
. The probes P
1
and P
2
are laid out in such an arrangement that a horizontally polarized wave and a vertically polarized wave are taken in with a highest degree of efficiency.
In the conductive-transmission-line waveguide converter explained above by referring to
FIGS. 1 and 2
, 2 probes, that is, a horizontal probe and a vertical probe, can be formed on the same planar wiring board. Thus, the conductive-transmission-line waveguide converter offers a merit of a small size and a low manufacturing cost in comparison with a converter wherein a polarized-wave splitter is provided at a location in the middle of an electromagnetic-wave transmission route inside the waveguide for splitting a cross-polarized wave into horizontally polarized-wave and vertically polarized wave components.
Since the probe P
1
for taking in a horizontally polarized wave and the probe P
2
for taking in a vertically polarized wave are placed on the same planar wiring board, however, there is a tendency to a difficulty to obtain a good cross-polarization characteristic.
SUMMARY OF THE INVENTION
It is thus an object of the present invention addressing the problem described above to provide a conductive-transmission-line waveguide converter that has 2 probes placed on the same planar wiring board and provides good cross-polarization characteristics wherein one of the 2 probes is used for taking in a horizontally polarized wave and the
Honma Katsunori
Yoshida Yoshikazu
Frommer William S.
Frommer & Lawrence & Haug LLP
Phan Tho
Smid Dennis M.
LandOfFree
Conductive transmission line waveguide converter, microwave... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Conductive transmission line waveguide converter, microwave..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Conductive transmission line waveguide converter, microwave... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2904566