Wave transmission lines and networks – Plural channel systems – Nonreciprocal gyromagnetic type
Reexamination Certificate
1999-05-11
2001-03-27
Bettendorf, Justin P. (Department: 2817)
Wave transmission lines and networks
Plural channel systems
Nonreciprocal gyromagnetic type
C333S024200
Reexamination Certificate
active
06208218
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a nonreciprocal circuit device using a dielectric wave guide, a dielectric wave guide device incorporating the nonreciprocal circuit device, and a radio device using the dielectric wave guide device.
2. Description of the Related Art
A conventional circulator using a nonradiative dielectric wave guide (hereinafter an “NRD guide”) has been described in Electronic Data Communications Academy Bulletin EMCJ92-54, MW92-94 (1992-10) “60 GHz Band NRD Guide Gunn Oscillator,” and Electronic Data Communications Academy Research Papers C-I, Vol. J77-C-I, No. 11, pp. 592-598, November 1994, “60 GHz Band FM Gunn Oscillator using an NRD Guide”.
FIG. 9
shows a conventional configuration of a circulator using the above NRD circuit. In
FIG. 9
, three dielectric strips
3
,
4
and
5
are provided between two conductive plates
1
and
2
to form an NRD guide, and ferrite plates
6
and
7
are provided at the portion where these three dielectric strips join. Then, magnets
8
and
9
are provided so as to sandwich the ferrite plates
6
and
7
from outside the conductive plates
1
and
2
.
A ferrite resonator comprising the ferrite plates
6
and
7
is excited by an electromagnetic wave which is transmitted through the dielectric strips. A DC magnetic field is applied vertically to the surfaces of the ferrite plates
6
and
7
. At this time, due to the ferromagnetic characteristics of the ferrite plates, the permeability of the ferrite plates differs depending on the direction in which the high-frequency magnetic field rotates, and as a result the polarized wave faces rotate, functioning as a circulator.
However, in the conventional circulator using an NRD guide shown in
FIG. 9
, the DC magnetic field is not applied efficiently to the ferrite plates, since only single-body magnets are provided for this purpose. Furthermore, leakage of the magnetic field from the single-body magnets affects the other components, and when other magnetic bodies are nearby, there is a possibility that the DC magnetic field applied to the ferrite plates may be affected and varied adversely.
It has been considered to include a closed magnetic circuit of the type used in a circulator for the microwave band (without an NRD guide), in the circulator for the millimeter wave band using an NRD guide as described above. However, the NRD guide presents special problems. That is because an NRD guide has a particular configuration wherein a dielectric strip, used as a transmission line, passes between upper and lower conductive plates, and consequently steps must be taken to ensure that the electrical field of the dielectric strip is not affected. Therefore, the conventional closed magnetic circuit that is used in the conventional circulator in the microwave band cannot be used together with the NRD guide without alteration.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a nonreciprocal circuit device including a dielectric wave guide in which the problems described above have been solved, a dielectric wave guide device incorporating the nonreciprocal circuit device, and a radio device using the dielectric wave guide device.
The nonreciprocal circuit device of the present invention comprises a dielectric wave guide comprising dielectric strips provided between two substantially parallel conductive planes, the dielectric strips being in contact with the conductive planes, ferromagnetic plates which are provided substantially parallel to the conductive planes and in the vicinity of end faces of the dielectric strips, a magnetic field source such as a magnet disposed in at least one position, and another magnetic field source such as a magnet or a magnetic pole being disposed in another position to sandwich the ferromagnetic plates, and magnetic members forming a closed magnetic path between the magnet and the other magnet or the magnetic pole.
Thus, since a magnet and another magnet or a magnetic pole are disposed to sandwich ferromagnetic plates, such as ferrite plates, and magnetic members form a closed magnetic circuit between the magnet and the other magnet or the magnetic pole, leakage of magnetic field from the magnet is suppressed and the strength of the DC magnetic field applied to the ferromagnetic plates increases even without increasing the magnetomotive force of the magnets. Further, the effect of leakage of magnetic field to other components is reduced, and changes in the DC magnetic field applied to the ferromagnetic plates due to a nearby magnetic body are reduced.
The magnetic members sandwich the dielectric wave guide, the magnet, and the other magnet or magnetic pole, and in addition, the magnetic members form side walls of the dielectric wave guide. The magnetic members may include magnetic yokes or plates made of magnetic material, and such magnetic plates may be connected by screws made of magnetic material so as to secure the magnet and the other magnet or magnetic pole. With this constitution, the dielectric wave guide and the magnets can be joined together by the magnetic members.
The dielectric strips are arranged at respective angles of approximately 120° with the ferromagnetic plates in the center, and the magnetic members are provided in positions between respective pairs of dielectric strips, at respective angles of approximately 120° with the ferromagnetic plates in the center. It is therefore possible to achieve a three-port circulator.
The magnetic members are provided at a distance from the dielectric strips which is equal to or greater than ¼ of the wavelength on the dielectric wave guide. As a result, the magnetic members have almost no influence on the electromagnetic field of the dielectric wave guide.
The invention also relates to a dielectric wave guide device, comprising the above-described nonreciprocal circuit device, and further including a dielectric wave guide, thereby providing a dielectric wave guide circuit such as a coupler or a primary radiator, for example.
The invention relates further to a radio device, such as a radar module, for example, comprising a primary radiator, a transmission portion and/or a receiving portion, in combination with the above-described dielectric wave guide device.
The above, and other features and advantages of the invention will be better understood from the following description of embodiments thereof, with reference to the drawings.
REFERENCES:
patent: 3246261 (1966-04-01), Stelzer
patent: 4276522 (1981-06-01), Coerver
patent: 5781086 (1998-07-01), Kato et al.
patent: 0700113 (1996-03-01), None
Hiroyuki Yoshinaga Et Al.; “Design and Fabrication of a Nonradiative Dielectric Waveguide Circulator” IEEE Transactions on Microwave Theory and Techniques, vol. 36, No. 11, Nov. 1, 1988 (Nov. 1988), pp. 1526-1531, FIG. 1.
Ishiura Yutaka
Ohira Katsuyuki
Tokudera Hiromu
Bettendorf Justin P.
Murata Manufacturing Co. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
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