Communications: radio wave antennas – Antennas – Slot type
Reexamination Certificate
2001-08-15
2003-02-11
Le, Hoanganh (Department: 2821)
Communications: radio wave antennas
Antennas
Slot type
C343S767000, C343S7000MS
Reexamination Certificate
active
06518932
ABSTRACT:
TECHNICAL FIELD
The present invention relates to radio communication devices for pseudo-millimetric and millimetric wavebands and to a compact radio communication device in which an antenna and a high-frequency unit are integrated with each other.
BACKGROUND ART
Conventionally, in a frequency region below the microwave band, a radio communication device has been used by independently designing and manufacturing a high-frequency unit formed of a frequency converter circuit, a local oscillator circuit, an amplifier circuit and so on and an antenna and connecting them by means of a connector or mounting them on an identical substrate. However, in the pseudo-millimetric and millimetric waveband regions of higher frequencies, losses in a power supply line and connecting portions between the high-frequency unit and the antenna rapidly increase, and this has been a serious problem in providing a practicable efficient device.
In order to solve this problem, there is needed a structural technology in which the antenna and the high-frequency unit are integrated with each other for the frequencies higher than the pseudo-millimetric and millimetric wavebands. The antenna element and the antenna have the same meaning.
As a concrete measure against these problems, Japanese Patent Laid-Open Publication No. HEI 10-79623 discloses one example of a radio communication device in which an antenna and a high-frequency unit are housed in an identical package.
According to Japanese Patent Laid-Open Publication No. HEI 10-79623, a substrate on the identical surface of which the antenna element and the high-frequency unit are formed and a package conductor for hermetically sealing the antenna element and the high-frequency unit formed on the substrate in a common space are provided, and a partial region that belongs to the package conductor and faces the antenna element is nonconductive.
In another example shown in FIG. 7 of Japanese Patent Laid-Open Publication No. HEI 10-79623, a conductive shield plate for preventing electromagnetic mutual interferences is provided between a high-frequency unit and an antenna element.
An example of a combination of an NRD (nonradiative dielectric) wave guide (nonradiative dielectric line), a dielectric resonator and a dielectric lens is disclosed in C-172 of General Meeting in 1996 of The Institute of Electronics, Information and Communication Engineers. Radiation is made in the vertical direction from the NRD circuit surface by converting the LSM01 mode that is the propagation mode of the NRD guide into the HE11 mode of the dielectric resonator and further making excitation of a slot on the resonator, and a beam is formed by means of the dielectric lens. By virtue of the use of a dielectric resonator of a high Q value and an NRD guide of a very little transmission loss, the losses between the high-frequency unit and the antenna can be restrained. The system that employs the NRD guide is often used in the communication system for the millimetric waveband.
An example in which a multislot antenna and a frequency converter unit are integrated with each other is disclosed in C-2-52 of General Meeting in 1998 of The Institute of Electronics, Information and Communication Engineers. According to this, a multislot antenna and a coplanar transmission line connected to the multislot antenna are formed in a pattern on a dielectric substrate, and a frequency converter circuit is formed at the other terminal of the coplanar transmission line. An RF signal received by the multislot antenna passes through the coplanar transmission line so as to be inputted to the frequency converter circuit, while a local oscillation signal is inputted from an LO terminal. The RF signal is mixed with the local oscillation signal in the frequency converter circuit so as to be frequency converted and outputted as an IF signal from an IF terminal.
The multislot antenna is suitable for millimetric waveband communications characteristic of a wide band property for the reasons that matching can easily be achieved by adjusting the number of slots and that a wide bandwidth can be provided in comparison with the patch antenna and the like.
The radio communication device for the frequency region below the microwave band has conventionally been used by independently designing and manufacturing a high-frequency unit formed of a frequency converter circuit, a local oscillator circuit, an amplifier circuit and so on and an antenna and connecting them by means of a connector or mounting them on an identical substrate.
However, in the pseudo-millimetric and millimetric waveband regions of higher frequencies, a loss in the power supply line between the high-frequency unit and the antenna rapidly increases, and therefore, it has been an important problem to integrate the high-frequency circuit section and the antenna in providing a practical high-efficiency radio communication device.
By virtue of the development in the high-frequency semiconductor device technologies, devices for microwave to millimetric wavebands can lately be provided in the form of an integrated circuit (MMIC (monolithic microwave integrated circuit)). For the microwave band, a variety of flat antenna technologies are developed and array antenna technologies coping with the increase in antenna gain practically needed have been achieved. In contrast to this, in the pseudo-millimetric and millimetric wavebands of higher frequencies, it is difficult to provide a high-efficiency high-gain antenna by the method of using an array antenna similar to that of the microwave band due to the losses rapidly increasing in the power supply line and the connecting portions with the increase in frequency.
In order to popularize the millimetric waveband technologies, it has been required to develop a new antenna technology of a small size and light weight capable of reducing the cost by mass production.
On the other hand, in the far-infrared and submillimetric wavebands of wavelengths shorter than that of the millimetric wave, a quasi-optical technology with a dielectric lens antenna, which is a receiver technologies for scientific researches of radio astronomy and so on, has been put into practical use as an optical method.
An example of the use of a combination of a thin film detection element constructed based on the geometrical-optical design method and a lens is described in “A Monolithic 250 GHz Schottky-Diode Receiver” IEEE TRANSACTIONS ON THEORY AND TECHNIQUES, VOL. 42, NO. 12, DECEMBER 1994” As shown in
FIG. 19
, this receiver unit, in which an antenna and a high-frequency detection element are integrated with each other, is constructed of a high-resistance silicon lens
90
, a polyethylene matching cap
91
, a silicon substrate
92
, and a receiver
94
formed on a gallium arsenide substrate
93
. Normally, according to the design based on optical technologies, both the diameter of the lens and the distance between the lens and the light-concentrating surface need ten or more wavelengths, and therefore, the diameter of an extended hemisphere lens amounts to about eleven wavelengths of the wavelengths in the air in the example of the aforementioned technical report. Furthermore, a distance from the center of the hemisphere to the substrate is extended with the lens material, providing an antenna with a basically three-dimensional structure. When the aforementioned quasi-optical lens technology is used, at the millimetric wave of a frequency of 100 GHz or less, which is expected to be put into practical use in the near future, the lens has a large actual size and a heavy weight and is not suitable for mass production, resulting in a high-cost large structure. Moreover, a parabola antenna with a reflecting mirror, which is generalized in the radio astronomy, the satellite communication terrestrial station and the like, similarly becomes a device of a three-dimensional mechanical structure and is not regarded as a technology to be widely popularized in the future. An antenna device technology of a quite new concept has been strongly demanded in order t
Matsui Toshiaki
Yamada Atsushi
Birch & Stewart Kolasch & Birch, LLP
Communications Research Laboratory, Independent Administrative I
Le Hoang-anh
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