Wave transmission lines and networks – Wave mode converters
Reexamination Certificate
2000-11-20
2002-09-03
Pascal, Robert (Department: 2817)
Wave transmission lines and networks
Wave mode converters
C343S909000
Reexamination Certificate
active
06445260
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to polarized wave separators, and more particularly to a polarized wave separator for use in a receiving converter (a low noise blockdown converter, LNB) that receives radio wave from a broadcasting or communication satellite.
2. Description of the Background Art
Microwave being used in satellite broadcasting normally consists of two components. As typical microwave, circularly polarized wave includes clockwise polarized wave and counterclockwise polarized wave. Linearly polarized wave includes vertically polarized wave and horizontally polarized wave.
The receiving converter is required to efficiently separate such two components from each other, and a polarized wave separator is used for such separation of microwave. As a representative of conventional polarized wave separators for use in the receiving converters, a polarized wave separator for separating the components included in circularly polarized wave will now be described.
Referring to
FIGS. 24 and 25
, a pair of wave receiving probes
104
a,
104
b
is formed on a substrate
103
. A waveguide
101
is placed on one side of substrate
103
. A waveguide partition wall
101
a
in a stepped shape is formed within waveguide
101
, which partitions the interior of waveguide
101
into two portions.
A wave reflecting unit
102
is placed on the other side of substrate
103
. A wave reflecting unit partition wall
102
a
is formed within wave reflecting unit
102
, which partitions the interior thereof into two portions. A wave reflecting surface
102
b
is formed on an end surface of wave reflecting unit
102
opposite to substrate
103
.
On a surface of substrate
103
facing wave reflecting unit
102
, an earthed surface (pattern)
105
is formed along end surfaces of wave reflecting unit
102
and its partition wall
102
a
such that they contact with each other. On the other surface of substrate
103
facing waveguide
101
, another earthed surface (not shown) is formed along end surfaces of waveguide
101
and its partition wall
101
a
such that they contact with each other.
The earthed surface
105
for contact with wave reflecting unit
102
and the earthed surface for contact with waveguide
101
are electrically connected to each other via a through hole
106
. Thus, waveguide
101
and wave reflecting unit
102
are both maintained at an earth potential via substrate
103
.
The pair of wave receiving probes
104
a,
104
b
is formed on substrate
103
on its side facing wave reflecting unit
102
. Interconnection portions of wave receiving probes
104
a,
104
b
are electrically isolated from any of earthed surface
105
, wave receiving unit
102
and waveguide
101
.
Waveguide partition wall
101
a
and wave reflecting unit partition wall
102
a
act to partition the interior of waveguide
101
and wave reflecting unit
102
, respectively, into two wave-guiding spaces. Circularly polarized wave caught within waveguide
101
is separated by waveguide partition wall
101
a
and introduced into respective wave-guiding spaces.
The conventional polarized wave separators have configurations as described above.
With such a conventional polarized wave separator, however, there exist several problems conceivable as follows. To prevent the wave within waveguide
101
and wave reflecting unit
102
from externally escaping, or to reduce noise, it is necessary to ensure that respective end surfaces of partition walls
101
a,
102
a,
waveguide
101
and wave reflecting unit
102
contact their corresponding earthed surfaces.
If the secure contact between wave reflecting unit partition wall
102
a
and earthed surface
105
on substrate
103
is ensured, however, good contact between the end surface of waveguide
101
and the corresponding earthed surface may not be achieved.
As a result, the wave may escape from waveguide
101
, or the wave may not be separated successfully.
In addition, since wave reflecting unit
102
and waveguide
101
are electrically connected to each other via substrate
103
, there may arise a problem that the wave introduced into waveguide
101
will be attenuated by substrate
103
before reaching wave reflecting surface
102
b,
which results in further weakening of the wave. Hereinafter, such reduction in strength of the wave due to escape and/or attenuation will be referred to as “wave loss”.
SUMMARY OF THE INVENTION
The present invention is directed to solve the conceivable problems as described above. An object of the present invention is to provide a polarized wave separator that ensures separation of radio wave while suppressing escape of the wave, thereby reducing the wave loss.
A polarized wave separator according to the present invention includes a substrate portion, a pair of wave receiving portions, a waveguide, and a wave reflecting unit. The substrate has an opening portion. The pair of wave receiving portions is formed on the substrate on opposite sides in a radial direction of the opening portion. The waveguide is located on one side of the substrate portion, and has a partition wall portion provided therein. The wave reflecting unit is located on the other side of the substrate portion, and has a wave reflecting surface formed on its inner side. The waveguide, substrate portion and wave reflecting unit together form a wave-guiding space. The partition wall portion extends through the opening portion to the wave reflecting unit, and divides the wave reflecting surface into two portions. By the partition wall, the wave-guiding space is partitioned into two spaces, one in which one of the pair of wave receiving portions is located and the other in which the other of the pair of wave receiving portions is located.
According to this polarized wave separator, compared to the case of a conventional polarized wave separator in which the waveguide and the wave reflecting unit are located on respective sides of the substrate portion with no opening therein, the wave-guiding space formed by the waveguide, substrate and wave reflecting unit is partitioned by the single partition wall penetrating the opening formed on the substrate. Therefore, the separated wave caught in the respective wave-guiding spaces is prevented from escaping from one wave-guiding space to the other wave-guiding space both in the waveguide and in the wave reflecting unit near the substrate portion. This improves polarized wave-separating characteristics. In addition, the wave guided in the wave-guiding spaces is propagated to the wave reflecting surface without being interrupted by the substrate portion. This reduces the wave loss. Furthermore, the substrate portion is contacted only by the tubular portion of the wave reflecting unit and the waveguide, so that they both can make good contact with the substrate. Thus, it is possible to prevent the separated wave from escaping outside the waveguide or the tubular portion, so that the wave loss can be reduced.
Preferably, the waveguide is located such that the internal circumference of the waveguide encircles the opening portion. The wave reflecting unit includes the tubular portion that is located on the other side of the substrate portion from the waveguide, and an end surface portion that is located on an end of the tubular portion where a wave reflecting surface is formed. The partition wall portion contacts at least the end surface portion, so that it is electrically connected with the wave reflecting unit.
With such a configuration, conduction between the partition wall portion and the wave reflecting unit is ensured, so that the loss of the separated wave is alleviated. Further, it is possible to prevent escape of the separated wave from one wave-guiding space to the other wave-guiding space at least through a gap between the partition wall portion and the end surface portion, so that the separating characteristics are further improved.
To ensure that the partition wall portion and the wave reflecting unit are electrically connected in a good condition and the wave is prevented fro
Hirota Makoto
Miyazaki Ryoko
Glenn Kimberly E
Nixon & Vanderhye P.C.
Pascal Robert
Sharp Kabushiki Kaisha
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