EP0278070A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Circular microstrip vehicular rf antenna
Assignee: Ball Corp
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Filing: 1987-11-16
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Granted: —
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Expires: 2007-11-16
Abstract
Abstract A compact, easy to manufacture quarter-wavelength microstrip element especially suited for use as a mobile radio antenna has performance which is equal to or better than conventional quarter wavelength whip-type mobile radio antennas. The antenna is not visible to a passerby observer when installed, since it is literally part of the vehicle. The microstrip radiating element is conformal to a passenger vehicle, and may, for example, be mounted under a plastic roof between the roof and the headliner.
Inventors
- 👤 Russell Wayne Johnson
- 👤 Robert Eugene Munson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 05:16
CPC Classifications
H; H01; H01Q; H01Q9/00; H01Q9/04; H01Q9/0407; H01Q9/0464; H01Q1/00; H01Q1/27; H01Q1/32; H01Q1/325; H01Q1/3275; H01Q13/00; H01Q13/10; H01Q13/18
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
148 words
A radio frequency antenna for vehicular installation, said antenna comprising: a conductive reference surface; a circularly shaped conductive radiator element of at least one-half wavelength in diameter disposed above said reference surface by substantially less than one-fourth wavelength and electrically shorted to said reference surface near the center of the circularly shaped element to form a shorted one-fourth wavelength radius annular cavity having a first circular radiating slot at its outer edge; an RF signal feed connection located between the reference surface and a predetermined matched impedance point on said circular radiator element; and at least one further annular conductive radiator element spaced radially outwardly from said first circular radiating slot and also disposed above said reference surface by substantially less than one-fourth wavelength, said further radiator element also having a resonant radial dimension to form at least one further circular radiating slot at one of its edges.
Claim 2
Dependent Claim
148 words
A radio frequency antenna for vehicular installation, said antenna comprising: a conductive reference surface; a circularly shaped conductive radiator element of at least one-half wavelength in diameter disposed above said reference surface by substantially less than one-fourth wavelength and electrically shorted to said reference surface near the center of the circularly shaped element to form a shorted one-fourth wavelength radius annular cavity having a first circular radiating slot at its outer edge; an RF signal feed connection located between the reference surface and a predetermined matched impedance point on said circular radiator element; and at least one further annular conductive radiator element spaced radially outwardly from said first circular radiating slot and also disposed above said reference surface by substantially less than one-fourth wavelength, said further radiator element also having a resonant radial dimension to form at least one further circular radiating slot at one of its edges.
Claim 3
Dependent Claim
48 words
A radio frequency antenna as in claim 1 wherein said further annular conductive radiator element has a radial dimension of substantially one-fourth wavelength and has its inner radius shorted to said reference surface to form an annular shorted one-fourth wavelength radius circular radiating slot at its outer edge.
Claim 4
Dependent Claim
27 words
A radio frequency antenna as in claim 1 wherein said second radiating slot is located about 0.2 to 0.4 wavelength radially outwardly of said first radiating slot.
Claim 5
Dependent Claim
45 words
A radio frequency antenna as in claim 1 wherein said further annular conductive radiator element comprises a passive parasitic director having no directly connected RF feedpoint but providing increased antenna gain at the horizon when said radiator elements and conductive reference surface are horizontally disposed.
Claim 6
Dependent Claim
37 words
A radio frequency antenna as in claim 1, 2, 3 or 4 comprising a plurality of said further annular conductive radiator elements, each successive additional such further element being located radially outwardly of the just preceding one.
Claim 7
Dependent Claim
28 words
A radio frequency antenna as in claim 1 installed in the roof of a vehicle with the conductive reference surface disposed over a passenger section of the vehicle.
Claim 8
Dependent Claim
51 words
A radio frequency antenna as in claim 1 wherein said RF signal feed connection includes a predetermined length of microstrip transmission line disposed on said radiator element and connected to resonate with other feed connection components so as to provide a substantially matched RF impedance over a broadened band of frequencies.
Claim 9
Dependent Claim
18 words
A radio frequency antenna as in claim 1 having an operational bandwidth including 825 MHz to 890 MHz.
Claim 10
Dependent Claim
16 words
A radio frequency antenna as in claim 1 wherein said conductive elements comprise die-formed aluminum structures.
Claim 11
Dependent Claim
136 words
A low profile UHF radio frequency antenna structure comprising: a first part comprising a conductive material, said first part having a circular periphery and first and second opposing surfaces, said first part also having a depression in substantially the center of said first surface and a cylindrical, hollow portion protruding from said second surface, said depression communicating with the hollow within said protruding portion, said protruding portion having a distal terminus; a second part comprising a conductive material, said second part having a substantially cylindrical depression surrounded by an outwardly extending flange, said cylindrical depression having a bottom portion; means for mechanically and electrically attaching said first part protruding portion terminus to said second part bottom portion; and an RF feedline connected between said second part and a predetermined impedance matching point on said first part.
Claim 12
Dependent Claim
136 words
A low profile UHF radio frequency antenna structure comprising: a first part comprising a conductive material, said first part having a circular periphery and first and second opposing surfaces, said first part also having a depression in substantially the center of said first surface and a cylindrical, hollow portion protruding from said second surface, said depression communicating with the hollow within said protruding portion, said protruding portion having a distal terminus; a second part comprising a conductive material, said second part having a substantially cylindrical depression surrounded by an outwardly extending flange, said cylindrical depression having a bottom portion; means for mechanically and electrically attaching said first part protruding portion terminus to said second part bottom portion; and an RF feedline connected between said second part and a predetermined impedance matching point on said first part.
Claim 13
Dependent Claim
12 words
An antenna structure as in claim 10 wherein said flange is annular.
Claim 14
Dependent Claim
27 words
An antenna structure as in claim 10 wherein said flange has a width which is approximately half the diameter of the circular periphery of said first part.
Claim 15
Dependent Claim
33 words
An antenna structure as in claim 10 wherein the bottom of said second part cylindrical depression is circular and has a diameter which is substantially larger than the diameter of said first part.
Claim 16
Dependent Claim
21 words
An antenna structure as in claim 10 wherein an annular gap is defined between said first part periphery and said flange.
Claim 17
Dependent Claim
18 words
An antenna structure as in claim 10 wherein said first part first surface and said flange are coplanar.
Claim 18
Dependent Claim
33 words
An antenna structure as in claim 10 wherein said attaching means includes: structure extending from said terminus; and at least one aperture defined through said bottom portion into which said structure is inserted.
Claim 19
Dependent Claim
21 words
An antenna structure as in claim 10 further including a sheet of conductive material coupled to said second part bottom portion.
Claim 20
Dependent Claim
19 words
An antenna structure as in claim 10 wherein said protruding portion is frustoconical where it joins said second surface.
Claim 21
Dependent Claim
40 words
An antenna structure as in claim 10 wherein said protruding portion includes a frustoconical portion and a cylindrical portion joined thereto, said cylindrical portion terminating in said terminus, said frustoconical portion being connected to the remainder of said first part.
References Cited (Backward Citations)
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