Communications: radio wave antennas – Antennas – Microstrip
Reexamination Certificate
1999-07-16
2001-04-10
Le, Hoanganh (Department: 2821)
Communications: radio wave antennas
Antennas
Microstrip
C343S850000, C343S853000
Reexamination Certificate
active
06215443
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a radar module and an antenna device for an FM millimeter-wave radar alarm system for use on motor vehicles.
2. Description of the Prior Art
One known motor vehicle radar alarm system has an electronically scanning planar antenna array as disclosed in U.S. Pat. No. 5,008,678. The disclosed electronically scanning planar antenna array comprises a plurality of transmitting and receiving planar antenna elements, a pair of passive phased arrays such as planar microstrip Butler matrixes, and a pair of electronic switches which are combined to transmit and receive a scanning beam.
The conventional electronically scanning planar antenna array is disadvantageous in that the passive phased arrays thereof cannot scan a relatively large angular range with the scanning beam. Another problem is that the planar antenna array requires both a transmitting array of antenna elements dedicated to transmitting radar signals and a receiving array of antenna elements dedicated to receiving echo signals. This imposes limitations on conventional systems which make it difficult to reduce the size of the planar antenna arrays used therein and, especially difficult to install such planar antenna arrays on motor vehicles.
German laid-open publication No. 4307009 discloses an antenna device for a radar module.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. MTT-26, NO. 1, JANUARY 1978, shows an MIC Doppler module with output radiation normal to the substrate plane.
Japanese patent publication No. 57-24968 discloses a microwave IC case.
Japanese laid-open utility model publication No. 1-126714 discloses an antenna device.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a radar module and an antenna device which are capable of scanning a relatively large angular range with a scanning beam and which are of a small size suitable for use particularly on motor vehicles.
According to one aspect of the present invention, there is provided a radar module comprising a dielectric substrate, an antenna assembly mounted on the dielectric substrate, the antenna assembly comprising a plurality of transmitting and receiving channels including respective planar array antenna elements each composed of a plurality of patches connected to and spaced along a linear distal end portion of a feeder line, the planar array antenna elements being arrayed in a direction substantially perpendicular to the linear distal end portion of the feeder line, a plurality of transmitting and receiving assemblies mounted as monolithic microwave integrated circuits on the dielectric substrate, for selectively transmitting high-frequency signals to the planar array antenna elements and selectively receiving echo signals from the planar array antenna elements, and a plurality of circulators mounted on the dielectric substrate and associated with the transmitting and receiving channels, respectively, the circulators connecting the respective linear distal end portions of the feeder lines to transmission and reception end portions which are connected to the transmitting and receiving assemblies, respectively.
The antenna assembly serves as a primary radiator of a defocused multiple-beam antenna. The planar array antenna elements are arranged to radiate respective electromagnetic waves at a predetermined tilt angle, the offset multiple-beam antenna having a secondary radiator positioned closely to the primary radiator.
According to another aspect of the present invention, there is also provided a radar module comprising a dielectric substrate, a plurality of planar array antenna elements mounted in respective channels on the dielectric substrate, and a plurality of monolithic microwave integrated circuits mounted on the dielectric substrate, the monolithic microwave integrated circuits including a plurality of transmitting assemblies for amplifying and supplying respective high-frequency signals to the planar array antenna elements, respectively, and a plurality of receiving assemblies for receiving echo signals from the planar array antenna elements and mixing the echo signals with amplified local signals related to the high-frequency signals.
In each of the above radar modules, the planar array antenna elements are divided into two groups, the planar array antenna elements of one of the two groups and the planar array antenna elements of the other of the two groups being arranged in an interdigitating pattern and disposed on respective linear distal end portions of feeder lines belonging to the respective groups and extending in opposite directions that are 180° apart from each other.
Alternatively, the planar array antenna elements may be divided into two groups, the planar array antenna elements of one of the two groups and the planar array antenna elements of the other of the two groups being disposed on respective linear distal end portions of feeder lines belonging to the respective groups and extending in opposite directions that are 180 apart from each other, and being positioned substantially in an end-to-end configuration and staggered with respect to each other in a direction across the feeder lines.
The high-frequency signals transmitted to the planar array antenna elements comprise frequency-modulated signals, the receiving assemblies including mixers for mixing echo signals from the planar array antenna elements with the frequency-modulated signals to thereby produce beat signals.
The transmitting assemblies include transmission amplifiers for amplifying the high-frequency signals, and the receiving assemblies include reception amplifiers for amplifying the local signals. A control circuit is provided for selectively operating the transmission amplifiers and the reception amplifiers.
According to still another aspect of the present invention, there is also provided an antenna device comprising a dielectric substrate, an array of antenna elements mounted on the dielectric substrate, each of the antenna elements comprising a plurality of patches interconnected in a direction transverse to the array, and a plurality of circulators mounted on the dielectric substrate and connected in series to the antenna elements, respectively.
The circulators are arranged in adjacent pairs, the circulators in each of the pairs being arranged such that DC magnetic fields in mutually opposite directions are applied to the circulators, respectively, for rotating signals in mutually opposite directions in the circulators.
The antenna device further comprises a scanning control circuit for switching the antenna elements in a time-sharing fashion.
According to still another aspect of the present invention, there is provided an antenna device comprising a dielectric substrate, a primary radiator comprising an array of antenna elements mounted on the dielectric substrate, each of the antenna elements comprising a plurality of patches interconnected in a direction transverse to the array, and a plurality of circulators mounted on the dielectric substrate and connected in series to the antenna elements, respectively, a secondary radiator for reflecting a beam radiated from the antenna elements, and a holder supporting the primary radiator integrally with the secondary radiator, with the primary radiator being positioned substantially at a focal point of the secondary radiator.
The above and other objects, features, and advantages of the present invention will become apparent from the following description when viewed in conjunction with the accompanying drawings which illustrate, by way of example, preferred embodiments of the present invention.
REFERENCES:
patent: 4742354 (1988-05-01), Wen et al.
patent: 4929956 (1990-05-01), Lee et al.
patent: 4933680 (1990-06-01), Shapiro et al.
patent: 4937585 (1990-06-01), Shoemaker
patent: 5008678 (1991-04-01), Herman
patent: 5206655 (1993-04-01), Caille et al.
patent: 5243354 (1993-09-01), Stern et al.
patent: 5264860 (1993-11-01), Quan
patent: 5333002 (1994-07-01), Gans et al.
patent: 5339083 (1
Komatsu Satoru
Urabe Masanobu
Honda Giken Kogyo Kabushiki Kaisha
Le Hoang-anh
Lyon & Lyon LLP
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