EP0432647A2
Expired / Lapsed
EP
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Mobile antenna system
Assignee: Toyota Central R&D Labs Inc
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Filing: 1990-12-06
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Granted: —
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Expires: 2010-12-06
Abstract
Abstract In mobile communications, it is required that the beam direction is maintained to track the desired direction as the mobile is moving. For such a purpose, the mobile includes an angular rate sensor mounted therein which detects the state of turn in the mobile and to control the beam direction of the antenna in accordance with the state of turn as well as the strength of radiowave received by a receiver in the mobile. Antenna elements (114) are in the form of microstrip antenna and are arranged in plane on the same dielectric substrate (113 or 112). Feeding and drive circuit layers (122, 124) for controlling the transmission and reception at the antenna elements are stacked into a single layered unit. This enables the antenna system to be formed into a low-profile structure. The dielectric substrate of the microstrip antenna element is formed by stacking a plurality of dielectric substrates (112, 113) different in dielectric constant from one another. It is thus intended that the band width of the antenna is increased and that the mutual coupling between the antenna elements is reduced to prevent the gain of the antenna from being lowered. Furthermore, the position of feed points in the antenna element are rotated against each adjacent antenna element. This can improve the axial ratio in the array antenna over a wide band width.
Inventors
- 👤 Kunitoshi Nishikawa
- 👤 Kazuo Nagakute-Shataku 501 Sato
- 👤 Tomoaki Hirako
- 👤 Mitoshi Nagakute-Ryo 215 Fujimoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 19:27
CPC Classifications
H; H01; H01Q; H01Q3/00; H01Q3/26; H01Q3/2605; H01Q1/00; H01Q1/27; H01Q1/32; H01Q1/3208; H01Q1/3233; H01Q21/00; H01Q21/06; H01Q21/061; H01Q21/065
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
81 words
A mobile antenna system comprising: a turn detecting section for detecting the state of turn in a mobile; an antenna controllable with respect to its beam direction; a receiving section for taking a signal proportional to the strength of radiowave received by said antenna; and a beam direction control section for changing the beam direction according to the turning angle of the mobile detected by said turn detecting section and also the strength of the radiowave received by said receiving section.
Claim 2
Dependent Claim
27 words
A mobile antenna system as defined in claim 1 wherein said turn detecting section includes an angular rate sensor for sensing the turning angle of the mobile.
Claim 3
Dependent Claim
199 words
A mobile antenna system as defined in claim 1 or 2 wherein said beam direction control means comprises: a satellite direction searching section for controlling the beam direction of said antenna over a broad range to obtain a higher strength in said received radiowave and to find the satellite direction; and a control selecting section for selecting one of control modes depending on said strength of received radiowave and said state of turn; said control modes selected by said control selecting section being at least three types: (a) an on-nonturning control selected when it is judged that the mobile is moving straight and adapted to change the beam direction of the antenna slightly so as to detect the direction of the highest strength of received radiowave; (b) an on-turning control selected when it is judged that the mobile is turning and adapted to change the beam direction of the antenna depending on the state of turn and also to select the direction of the highest strength of received radiowave; and (c) an on-blocking control selected when radiowave is blocked by buildings and trees and adapted to change the beam direction of the antenna depending on the state of turn.
Claim 4
Dependent Claim
117 words
A phased array antenna mounted on a mobile, comprising: an antenna element layer including a plurality of radiating elements which are formed on a ground plane through a dielectric substrate with a ground plane; a feeding network layer including a feeding network which consists of phase shifters and power dividers, these components being made of microstripline which are respectively connected with said plurality of radiating elements and disposed on a dielectric substrate; and a drive circuit layer including a drive circuit which is connected with said phase shifters in said feeding network and adapted to supply a signal for controlling said phase shifters, said antenna element, feeding network and drive circuit layers being stacked one above another.
Claim 5
Dependent Claim
46 words
A phased array antenna as defined in claim 4 wherein each of the phase shifters in said feeding network layer made of a plurality of microstrip-lines different in length from one another, said microstrip-lines being selected to change the value of phase shift by switching means.
Claim 6
Dependent Claim
35 words
A phased array antenna as defined in claim 4 or 5 wherein said switching means operates to turn on and off PIN diodes which are formed on each of said microstrip-lines at the opposite ends.
Claim 7
Dependent Claim
34 words
A phased array antenna as defined in any of claims 4 to 6 wherein said phase shifters have three types of phase shift amounts corresponding to 45 ° , 90° and 180 ° .
Claim 8
Dependent Claim
27 words
A phased array antenna as defined in any of claims 4 to 7 wherein the power dividers in said feeding network layer are made of microstrip line.
Claim 9
Dependent Claim
50 words
A phased array antenna as defined in any of claims 4 to 8 wherein said antenna element lyaer and feeding network layer are shared by a common ground plane and wherein said antenna elements and feeding network layers are formed on said common ground plane at the opposite sides thereof.
Claim 10
Dependent Claim
42 words
A phased array antenna as defined in any of claims 4 to 9 wherein said feeding network layer is opposed to said drive circuit layer and wherein said feeding network and drive circuit layers are connected with each other through detachable connectors.
Claim 11
Dependent Claim
57 words
A phased array antenna as defined in any of claims 4 to 10 wherein the phase shifters and power dividers in said feeding network layer are formed by striplines in on the dielectric substrate between the ground plane on the side of the antenna layer and the ground plane on the side of the drive circuit layer.
Claim 12
Dependent Claim
41 words
A phased array antenna as defined in any of claims 4 to 11 wherein said drive circuit layer includes drive circuits formed on the substrate which is fixedly mounted on the ground plane on the side of the drive circuit layer.
Claim 13
Dependent Claim
119 words
A phased array antenna as defined in any of claims 4 to 12 wherein each of said radiating patch elements in said antenna layer includes two feed points with 90° difference in angle about the center thereof, the positions of two feed points rotated about the center thereof such that each of said radiating patch elements is excited in a circular polarization mode and wherein said radiating patch elements are arranged into a regular triangle lattice in three directions and have the set of three positions of feed points angularly different from one another by 120 degrees, the position of feed points in one of said radiating patch elements being different from that of any adjacent radiating patch element.
Claim 14
Dependent Claim
119 words
A phased array antenna as defined in any of claims 4 to 12 wherein each of said radiating patch elements in said antenna layer includes two feed points with 90° difference in angle about the center thereof, the position of two feed points rotated about the center thereof, such that each of said radiating patch elements is excited in a circular polarization mode and wherein said radiating patch elements are arranged into a regular triangle lattice in three directions and have the set of four positions of feed points angularly different from one another by 90 degrees, the position of feed points in one of said radiating patch elements being different from that of any adjacent radiating patch element.
Claim 15
Dependent Claim
61 words
A microstrip antenna element suitable for use in a mobile antenna system, comprising: a ground plane; a driver patch element disposed opposed to said ground plane through a dielectric substrate; and a driven patch element disposed spaced away from said driver patch element, said dielectric substrate being formed by stacking two or more dielectrics different in dielectric constant from one another.
Claim 16
Dependent Claim
17 words
A microstrip antenna element as defined in claim 15 wherein said dielectric stack is of three-layer structure.
Claim 17
Dependent Claim
55 words
A microstrip antenna element as defined in claim 16 wherein the two upper and lower layers in said three-layer dielectric stack are made of a dielectric substrate having the same dielectric constant and the intermediate layer is made of a dielectric substrate having a dielectric constant different from that of said upper and lower layers.
References Cited (Backward Citations)
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